arXiv:1505.01747v1 [astro-ph.SR] 7 May 2015 enucvrdi iefil uvy,sc sGU as indeed such surveys, have wide-field in objects A uncovered to planetary-mass been . accessible of nearby readily gravita- handful for is be observations Gyrs would seeing-limited planet for region a the bound of where a tionally most eclipse overlooked: a ) often around 2008 is al. that et fact Kalas 2008, companion, al. lhaut’s et nearby Marois around system, 2010; HR8799’s (e.g., of stars imaging contrast Introduction 1. 18 uc eteVle ot´a,Q,HC37 Canada 3J7, H3C Montr´eal, QC, Centre-Ville, C.P. Montr´eal, Succ. 6128, Universit´e de Physique, D´epartement de uino ahntn ahntn C205 USA 20015, DC Washington, Washington, of tution aaao iha,Kmea I973 USA 96743, HI Kamuela, Highway, Mamalahoa ahntn oiae io ail 0,L eea Chile Serena, La 601, Casilla Pino, el Colina Washington, ten Artigau Etienne ´ 1 2 3 4 h pcaua icvre ruh nb high- by on brought discoveries spectacular The ntttd ehrh u e xpa`ts(IREx), Exoplan`etes les sur Recherche de Institut eateto ersra ants,Crei Insti- Carnegie Magnetism, Terrestrial of Department aaaFac-aaiTlsoeCroain 65-1238 Corporation, Telescope Canada-France-Hawaii a apnsOsraoy angeIsiuinof Institution Carnegie Observatory, Campanas Las β uvy.Wt oe-eedn aso 21 M 12–15 of uncovere mass companions for model-dependent cha possible a its is With enabling of than optics, list surveys. instruments adaptive short of of very aid the suite the joins wider without it study ratio, to contrast amenable modest a and AU) (160 ainhsbe icvrdwt eiglmtddrc mgn observa imaging direct seeing-limited with discovered been has panion erho nw iia opnosmyb u oosrainlbias observational ratio to headings: mass Subject due versus be mass may host companions the searches. similar of companion known part ye few of populated last dearth sparsely the in a uncovered s in objects near-infrared similar falls various present to We it regimes. compare mass and dwarf brown and planet M6 wr/lntms ii oaTcn-oooimMdwarf M Tucana-Horologium a to limit dwarf/planet-mass itrsb arnee l 00 Foma- 2010; al. et Lagrange b, Pictoris erpr h icvr fasbtla opno o2ASJ02192 2MASS to companion substellar a of discovery the report We AYN I icvr facmaina h brown the at companion a of Discovery VI. BANYAN. γ addt ebro h uaaHrlgu soito (30 association Tucana-Horologium the of member candidate 1 oahnGagn´e Jonathan , edcrepnec [email protected] to correspondence Send Ren´e Doyon 1 ai Lafreni`ere David , 1 aqeieFaherty Jacqueline , ABSTRACT 1 tr ik,btol rudmsie( massive around only but protoplan- disks, unstable etary gravitationally wide in within form may orbits es- companions (2013) wide Vorobyov that 1997). tablished grav- disks accretion Boss or protoplanetary 1978; core 2005) (Cameron within al. either et instability Alibert by itational 1996; formation al. et situ (Pollack in for for- planetary orbits to models. wide challenge mation and such significant on 2014), a companions al. presents of 2010; et Naud presence al. et 2011; the (Goldman al. hosts and et Burningham 2000 their respectively from 458(AB)c, AU 1200 Ross and b Psc cini lopasbe u ean ob tested be to remains but plausible, systems. inter- also such is planet-planet action of through existence migration alter- the viable Outward a explain is pre-stellar to 2002) native a later-type Nordlund & of or (Padoan of fragmentation core stars Turbulent discovery K the hosts. around for companions account such cannot and disks, ot ihmsie( massive with hosts Jup hs opnosaeo ristolarge too orbits on are companions These tsrdlstebudr ewe the between boundary the straddles it , 1 uiBeletsky Yuri , 2 io Malo Lison , etocp fti companion this of pectroscopy on o-ascompanions low-mass young r.TeJ2932 system J0219–3925 The ars. − yhg-otatimaging high-contrast by d atrzto ihamuch a with racterization 0Mr.Ti L4 This Myr). 40 iga o iais the binaries; for diagram in;a 4 a at tions; si rvoslow-mass previous in es 1–952,ayoung a 210–3925225, > 4 3 0 ai-v Naud Marie-Eve , . M 2 ⊙ ′′ protoplanetary ) separation γ com- > 0 . M 7 ⊙ 1 ) , as a credible mechanism at such separations and metric follow-ups of the companion and its host mass ratios (Veras et al. 2009). Statistical anal- are described in section 3. Results are described yses of the mass, age and separation of planets in section 4 and discussed in section 5. uncovered through high-contrast imaging cam- paigns suggest that these companions constitute 2. The survey a low-mass tail of the distribution and are therefore the results of disk or cloud frag- J0219–3925 has been observed as part of a sur- vey of 300 stars conducted at the CTIO-1.5m mentation. The dearth of low-mass (< 5 MJ ) companions found by direct imaging surveys with telescope with the SIMON. This survey was un- adaptive optics (AO) can be explained in that dertaken following the discovery of the planetary- context (Brandt et al. 2014). This analysis mostly mass companion around the M3 AB Doradus contrains the occurence of companions out to 100- member GU Psc (Naud et al. 2014), in an attempt 200 AU; whether this paucity of companions holds to identify additional comparable planetary-mass for more distant brown dwarfs and planetary-mass companions and assess their overall frequency. companions remains to be determined in a statis- The target sample consists of both confirmed and tical framework. Overall, much work needs to be strong members of young moving groups within done to understand the origin and demographics 70pc (< 120 Myr; β Pictoris, AB Doradus, THA, of these distant companions, both theoretically Columba, Carina and Argus), and it was as- and observationally. sembled from objects in Malo et al. (2013) and Gagn´eet al. (2015). For each star, the Bayesian These distant companions have distinct ad- Analysis for Nearby Young AssociatioNs II tool vantages compared to either isolated planetary- (BANYAN II; Gagn´eet al. 2014c) provided a sta- mass objects or planets detected through AO sur- tistical distance estimate, allowing us to derive a veys. The presence of a host star allows a cross- projected distance for putative companions. calibration of the properties of the planet (paral- lax, mass, age, , membership to a young By combining SIMON J-band imaging with group), and the projected separation to that host WISE photometry (Wright et al. 2010), we iden- is sufficient to allow direct study through means tified objects that had a similar position to brown not compatible with extreme-AO, such as accurate dwarfs or known very-low gravity L dwarfs in an − spectro-photometry, high-resolution spectroscopy, MW 1 vs J W 2 diagram, but that did not have optical imaging, etc. Indeed, the detailed analysis optical digitized sky survey (DSS) counterparts. performed with intermediate-resolution spectro- In a way similar to the survey that allowed photometry on GU Psc b and Ross 458(AB)c will the discovery of GU Psc b, candidates were then be impossible to obtain in the near future for ex- followed-up with Gemini-South using deep i and z oplanets uncovered by AO surveys. band imaging to confirm the very red i−z color ex- As distant companions of nearby young stars pected for an L or T dwarf. The selection methods provide important benchmarks to understand self- will be detailed in a future paper (Artigau et al. luminous gas giants, we undertook various seeing- in preparation), as refinement of selection methods limited observations using the SIMON near- and follow-up of candidates are still ongoing. infrared spectro-imager (Doyon et al. 2000) at As the SIMON observations have significantly the CTIO-1.5m telescope and GMOS-S at Gem- better resolution than 2MASS (∼1′′ versus ∼2′′ ini South in order to identify such new objects full-width at half maximum) and are significantly through their distinctive far-red and near-infrared deeper (10 σ at J ∼ 18), they provide an oppor- colors. We report here a first discovery from tunity to identify relatively tight (2 − 6′′) over- this survey; a co-moving companion to 2MASS looked companions. We performed a radial profile J02192210–3925225 (J0219–3925), an M6 γ candi- subtraction on all primaries and visually inspected date member of the Tucana-Horologium associa- the residuals. Through this process, a single can- tion (THA) that has a low-gravity L4 γ compan- didate was identified, at an angular distance of ion. about 4′′ from the M6 star J0219–3925. No other The survey that led to this discovery is de- star within our sample presented a similar candi- − ′′ scribed in section 2. The discovery and photo- date companions within in a 2 6 annulus down

2 to a contrast of ∆J < 5.

3. Observation and reduction

3.1. Imaging The J-band discovery dataset of J0219–3925 g, GMOS i, GMOS was obtained with SIMON on 2013 November 5 6 6 at the CTIO, and follow-up H and Ks-band imag- 4 4 ing were obtained on 2014 February 2, with the 2 2 same instrument and telescope. For all 3 imaging 0 0

−2 −2 sequences, we employed a 4-point dither pattern DEC offset (") DEC offset (") ′ ′ along the corners of a 2 × 2 square. At each −4 −4 dither position, 15 images (J) and 5 images (H −6 −6 6 4 2 0 −2 −4 −6 6 4 2 0 −2 −4 −6 and Ks) were taken. All sequences used a 30s RA offset (") RA offset (") per-frame exposure time. The images were sky- J, SIMON J, F2 subtracted using a sky frame constructed from the 6 6 median combination of all science images taken 4 4 on that night within that band. Flat-fielding was 2 2 performed with a flat constructed from images of 0 0 −2 −2 a flat screen. The astrometric solution was per- DEC offset (") DEC offset (") formed using a cross-match of the 2MASS cata- −4 −4 −6 −6 log with field stars. All images were registered 6 4 2 0 −2 −4 −6 6 4 2 0 −2 −4 −6 and median-combined to produce the final science RA offset (") RA offset (") frame. K, 2MASS Gemini giJ 10 The contrast ratio between the two components 6 4 was determined by performing a PSF fitting of 5 2 the two J0219–3925 components using two isolated ′ 0 0 bright and nearby field stars (< 2.5, J > 13.5) as −2 DEC offset (") DEC offset (") −5 input PSFs. The magnitude of J0219–3925B was −4

then determined from the 2MASS magnitude of −6 −10 6 4 2 0 −2 −4 −6 10 5 0 −5 −10 its host and its contrast ratio within each near- RA offset (") RA offset (") infrared bandpass. The presence of the compan- ion is unlikely to have significantly affected the Fig. 1.— J0219–3925 system in SIMON, Flamin- 2MASS magnitudes of its host, as it contributes gos 2 (F2), GMOS and 2MASS imagery. Despite only 2 to 4% of the total integrated flux and is modest constraints provided by the 2MASS image resolved (∼ 2 FWHM). on the position of J0219–3925B, the ∼15 yr delay Upon discovery of a possible faint companion to between these archival observations and our dis- J0219–3925, we noticed that images of that field covery images provides significant constraints on usable for science were present in the Gemini sci- the common (see section 4.4). For ence archive (See Figure 1). GMOS-South (i and all images, East is left, North is up. The color g-band) and Flamingos-II (J-band) spectroscopic image is a combination of g, i and F2 J-band im- acquisition images of the host star have been ob- ages respectively coded as blue, green and red with tained as follow-up observations of the BANYAN arbitrary scaling. One readily sees that J0219– All-Sky Survey (BASS; Gagn´eet al. 2015). The 3925 B is much redder than its host. ∆i =6.22 contrast and non-detection in g (∆g > 5.5) pointed toward an object much redder than the mid-M host, prompting for a dedicated spec- troscopic follow-up of the companion. Inspec- tion of the K-band 2MASS images taken in 1999 shows that the companion is marginally detected

3 Table 1: Imaging and spectroscopy datasets for the J0219–3925 system Instrument Date Filter Number Per-frame Comment of exposures exposure time where applicable Gemini program ID GMOS-S 17/09/2012 g 1 10.5 s Spectroscopy acquisition GS-2012B-Q-70 GMOS-S 02/11/2012 i 1 10.5 s Spectroscopy acquisition GS-2012B-Q-70 SIMON 05/11/2013 J 60 30 s Discovery imaging SIMON 12/02/2014 H 20 30 s Photometric follow-up SIMON 12/02/2014 Ks 20 30 s Photometric follow-up F2 28/10/2013 J 1 5 s Spectroscopy acquisition GS-2013B-Q-79 FIRE 13/02/2014 ··· 2 306s J0219–3925,spectroscopy FIRE 13/02/2014 ··· 4 909s J0219–3925B,spectroscopy F2 04/09/2014 J 27 54s Imagingforastrometry GS-2014B-Q-72

and provided valuable constraints on the common and its companion are compared to field and low- proper motion of the pair (see Section 4.4 and Ta- gravity objects of comparable spectral types in ble 3). Figure 2. The spectrum of J0219–3925B has an average S/N of ∼ 30 when sampled at an R = 800 3.2. Spectroscopy resolution. On 2014 February 13, we obtained near-infrared 4. Results spectroscopic observations with the Folded-Port Infrared Echelette (FIRE; Simcoe et al. 2013) at 4.1. Host star properties and membership the Magellan 6.5-m telescope. FIRE was used in its high-resolution echellette mode, providing J0219–3925 has been identified as a member of a spectral resolution R ∼ 5000 continuously over the THA by two teams independently. First, it the entire near-infrared domain (0.8−2.4µm). We is part of the 129 new late-type (K3 and later) used a slit width of 0′′. 6 under a 1′′. 2 seeing and an THA members identified by Kraus et al. 2014; airmass of 1.3 − 1.6 (J0219–3925B) and 1.8 − 1.9 their membership being established by Li and RV (J0219–3925A). The reference star for both ob- measurements, but lack parallaxes and is based jects was observed at the same airmasses. For on spectroscopic distances. Spectroscopic fitting J0219–3925B, we used an ABBA dither pattern of optical spectrum and overall SED of J0219– for improved sky subtraction on this relatively 3925 respectively lead to a spectral type estimate faint target, while for the brighter J0219–3925A of M4.9 ± 1.0 and M5.9 ± 0.3; these values are and reference star, the two exposures were taken consistent with the near-infrared spectral type of with an AB dither pattern. M6 γ determined here (see section 4.3). The they measure (10.6 ± 0.7kms−1) agrees Data reduction was performed using the stan- −1 dard FIREHOSE pipeline. Flat-field correction within 0.71kms with the expected radial veloc- was performed using flat frames derived from ity of a THA member in that line of sight. This dome flat images and telluric absorption at the is below the internal dispersion of THA velocities ∼ −1 time observation was derived from an A0V star ( 1kms ) and well below the cutoff in velocity (HD 17683) observation taken immediately before difference between members and non-members in ± −1 (J0219–3925B) and after (J0219–3925A) the sci- their analysis ( 3kms ). ence integration. The spectrum of the host star The host star J0219–3925 was identified in-

4 Table 2: Properties of the J02193925 system Shortname J0219–3925 J0219–3925B 2MASSname 02192210–3925225 a µα (mas/yr) 107.37 ± 2.27 a µδ (mas/yr) −34.95 ± 1.65 Statistical distanceb 39.4 ± 2.6pc Position angle 173.9 ± 0.2◦ Separation 3.96 ± 0.02′′ Sky-planeseparation 156 ± 10 AU B 18.50 ··· ∆gc > 5.5 ∆ic 6.6 R 15.23 ··· Id 13.42 ± 0.03 ··· e J2Mass 11.381 ± 0.026 ··· f JMKO 11.321 ± 0.026 15.54 ± 0.10 e H2Mass 10.811 ± 0.027 ··· f HMKO 10.855 ± 0.027 14.63 ± 0.10 e K2Mass 10.404 ± 0.025 ··· f KMKO 10.444 ± 0.025 13.82 ± 0.10 W 1g 10.148 ± 0.023 W 2g 9.901 ± 0.020 W 3g 9.614 ± 0.037 g vrad 10.6 ± 0.7 ··· v sin i 6.5 ± 0.4g ··· SpT M6 γh L4 γ EW Hα (A)˚ -7.02 ··· EW Li6708 (A)˚ 639.9 ··· FeHz 1.068 ± 0.001 1.040 ± 0.002 FeHJ 1.07 ± 0.01 1.20 ± 0.02 Ki 1.169µm 0.17 ± 0.08 0.6 ± 0.4 Ki 1.177µm 1.25 ± 0.06 0.71 ± 0.32 Ki 1.244µm ···i 3.0 ± 0.5 Nai 1.138µm 2.58 ± 0.08 2.4 ± 0.5 H-Cont 0.995 ± 0.001 0.963 ± 0.001 VOz 1.001 ± 0.001 1.372 ± 0.004

aGirard et al. 2011 bSee Gagn´eet al. 2014c for a discussion on the definition and the accuracy of the statistical distance. cOnly contrasts were derived in g and i, and not magnitudes measurements as the images were not taken under photometric conditions. dDENIS Consortium 2005 eSkrutskie et al. 2006 f The 2MASS to MKO transform has been determined for J0219–3925 from its FIRE spectrum. The companion’s contrast ratio has been determined with SIMON that uses MKO filters. gCutri et al. 2013 hKraus et al. 2014 give a M5.9 spectral type from SED fitting and a spectroscopic spectral type of M4.9. iThe spectrum of J0219–3925 B around the KI 1.244µm is strongly affected by bad pixels on the science array.

5 Fig. 2.— (left) Spectra of J0219–3925, compared to a field M6 dwarf (LP423) and an M6 γ (TWA8B). Both J0219–3925 and TWA8B show an H-band spectrum that is more peaked that that of the higher gravity LP423. The inset shows that full resolution spectra in the 1.12 − 1.20µm domain; the higher gravity LP423 shows much stronger NaI absorption at 1.138µm and a stronger KI doublet at ∼ 1.17µm. (right) Spectra of J0219–3925B, the young companion AB Pictorisb (data from Bonnefoy et al. 2014) and the field L3.5 dwarf GD 165 B (data from McLean et al. 2003). The H-band flux of J0219–3925 is noticeably more peaked than the two others, pointing toward a very low gravity (compare with middle panels in Figure 5). (both) Flux within each photometric bandpass has been normalized to that of J0219–3925A or J0219–3925B to highlight differences in the shape of the SED within each bandpass; normalization intervals are shown as straight black lines above spectra.

dependently as a candidate member of THA 2014) and typical signs of low-gravity in its NIR as part of the BASS survey. 2MASS and All- spectrum (see left panel of figure 2 and Sec- WISE photometry and were used tion 4.3). Within that spectral type, the presence to derive its membership probability to several of lithium (EW= 639.9 mA)˚ points to an age be- moving groups in the Solar neighborhood. The low ∼ 125 Myr. Adding this age constraint in the BANYAN II tool compare the input parameters BANYAN II analysis raises the THA membership to spatial, kinematic and photometric models of probability further (P=99.93%). In addition to young moving groups and the field population a membership likelihood, the BANYAN analysis using a naive Bayesian classifier. We refer the provides a kinematic distance to an average pre- reader to Gagn´eet al. (2014c) for details on this cision of ∼10% for young moving group members analysis. As J0219–3925 had been identified as (See Figure 5 in Malo et al. 2013 and Figure 8 in a high probability candidate of THA, it was in- Gagn´eet al. 2014c). The kinematic distance for cluded in our search for distant companions before J0219–3925 is 39.4 ± 2.6pc. The 7% uncertainty the publication of the bulk of the survey. The includes both the contribution from the uncertain- BANYAN II tool gives a P=99.34% probability ties on the proper motion of J0219 and the space that J0219–3925 is a member of THA. When such velocity scatter of THA members. measurements are available, the BANYAN II tool As an additional confirmation, we used J0219– can use the radial velocity and/or parallax to con- 3925 apparent Ic and J magnitudes, the amplitude strain membership probability further. Using the of the proper motion and the sky position to ver- −1 radial velocity of 10.6 ± 0.7kms measured by ify its membership probability in the BANYAN I Kraus et al. (2014), the THA membership proba- analysis (Malo et al. 2013). It yields an a priori bility of the host star increases to P=99.94%. probability of P=96.3% of membership in THA. We can set additional constraints on the age of Similarly to the BANYAN II analysis, it is possi- this object since it displays lithium (Kraus et al. ble to include the radial velocity as an additional

6 constraint in the analysis. When we do so, the age is in better agreement with the LDB age for probability is increased to Pν =99.9%. The statis- young low-mass stars. In general, isochronal ages tical distance inferred by this analysis is the same are revised upward with the inclusion of mag- as predicted by BANYAN II. netic fields. As shown in Malo et al. (2014b), magnetic field strength measurements from high- 4.2. The Age of THA resolution spectroscopy would further constrain its age. Pending such measurement, we conser- The Tucana and Horologium Associations were vatively adopt an age range of 30 − 40 Myr for discovered independently by Zuckerman & Webb the THA association, and thus, for J0219–3925 2000 and Torres et al. 2000. Further studies con- system. firmed that what was initially considered as two associations were more likely to constitute a sin- 4.3. Spectral type and Gravity Indicators gle young moving group to be called the Tucana- Horologium association (THA; Zuckerman et al. We used the method of K. Cruz et al. (in prepa- 2001). THA is part of the so-called Great ration; see Cruz & N´u˜nez 2007) to assign a spec- Austral Young Association (GAYA; Torres et al. tral type to both components of J0219–3925. This 2008), including the Columba and Carina as- method consists of a visual comparison with a grid sociations. Several studies (Zuckerman & Song of spectral templates while normalizing each NIR 2004; Torres et al. 2008; Kiss et al. 2011) pro- band individually. Inspecting the slope and shape posed members of THA based on their galac- of several features in each band allows to choose a tic space velocity, galactic position, and signs template that best matches the observations. Our of youth, yielding a sample of members with sequence of field, intermediate-gravity and low- spectral type between A1V and early-M spawn- gravity templates were build by median-combining ing a distance range of 36 to 71pc. Recent various objects within each spectral types and studies (Rodriguez et al. 2013; Mo´or et al. 2013; gravity class. The spectra used to build the tem- Malo et al. 2013; Gagn´eet al. 2014a,b,c; Kraus et al. plates were obtained from Allers & Liu (2013) and 2014) proposed more than 200 strong THA can- the SpeX Prism Spectral Libraries1. Both the vi- didate members, which still require more robust sual comparisons of J0219–3015 and b yielded best kinematics to confirm their membership. matches to very low gravity templates; J0219– The age range of THA was estimated to be 10− 3015 and its companion were assigned a spectral 40 Myr (Zuckerman et al. 2001; Zuckerman & Webb type of M6 γ and L4 γ respectively. The gravity 2000) based on various age indicators (Hα, classification scheme of Allers & Liu (2013) was lithium, HR diagram). More recently, Kraus et al. subsequently used to confirm that both objects 2014 derived an average isochronal age of 30 Myr have weaker alkali lines compared to field dwarfs using a new sample of 142 candidate members of the same spectral types, and that J0219–3015B combined with the BCAH models (Baraffe et al. has stronger VO absorption and a triangular- 1998). shaped H-band continuum (which was already ap- In addition to the isochronal age, the lithium parent from the visual comparison). Both objects depletion boundary (LDB) is a key indicator to were consistently categorized as very low gravity determine the age of the low-mass star popu- dwarfs by this index-based classification scheme. lation. This method was used by Kraus et al. We show that they both display typical spectro- 2014 to determine the THA lithium depletion scopic signatures of a low-gravity, including lower- I I age of 41±2 and 38±2 using the BCAH and than-normal alkali (K , Na and FeH) equiv- D’Antona & Mazzitelli 1997 models, respectively. alent widths. The lower gravity causes a lower pressure in the atmosphere, which decreases both This discrepancy between isochronal and LDB the effects of pressure broadening (responsible for ages was already demonstrated by several studies the lower alkali equivalent widths) and collision- (Song et al. 2002; Yee & Jensen 2010; Binks & Jeffries induced absorption (CIA) of the H molecule. The 2014). Recently, Malo et al. 2014a have shown 2 triangular H–band continuum is shaped by water that using new Dartmouth Magnetic evolutionary models (Feiden & Chaboyer 2013), the isochronal 1 http://pono.ucsd.edu/~adam/browndwarfs/spexprism

7 absorption. In the case of field brown dwarfs, the ∼3.8 × 10−3 pc−3 (Cruz et al. 2007), there should H2 CIA redirects part of the flux to the bluer side, be ∼5500 L dwarfs within 70 pc. The likelihood which masks the triangular shape of the H-band of finding a coincident L dwarf to a young star in continuum (see Rice et al. 2010 for further detail). our sample is about ∼ 3 × 10−4 without consider- Figure 3 illustrates the gravity-sensitive spectro- ing the fact that the L dwarf itself also displays a scopic indices defined by Allers & Liu (2013) for low surface gravity. both components of the J0219–3925 system. Orbital motion of the pair is expected to be The intermediate gravity and very low gravity close to the detection threshold. With a total classifications generally correspond to the β and γ mass of ∼0.12 M⊙ (see table 3) and a separa- gravity classifications in the optical (Kirkpatrick tion of ∼160AU, the orbital period is on the or- 2005; Kirkpatrick et al. 2006; Cruz et al. 2009), der of 6000yr. Assuming a face-on orbit, this hence we choose here to use the Greek-letter leads to an orbital motion of 4 mas/yr. Orbital nomenclature even though our gravity classifica- velocity is on the order of 800 m/s and within tion was done in the NIR. reach of upcoming high-resolution infrared spec- trographs such as VLT/CRIRES+ (Follert et al. 4.4. Kinematics and Common Proper Mo- 2014). Both measurements are challenging but tion possible with existing facilities, but not with the Astrometric measurements were performed on dataset in hand. Proper constraints on the dif- GMOS-S i-band, F2 J-band and SIMON imaging ferential motion within the system will allow one obtained on 2013 November 5. SIMON imaging to constrain whether the orbit of J0219–3925B is obtained in early 2014 were not included as they consistent with a circular orbit or a highly ec- were taken under poor seeing conditions (∼ 2′′) centric one. Constraints on orbital eccentricity and do not constrain proper motion. Archival for a few systems similar to J0219–3925 could set 2MASS imaging were also used; it provides only strong limits on the plausible formation mecha- modest constraints on the PA and separation, but nisms. These measurements would provide con- the long time baseline (∼15years) makes it a use- straints on the J0219–3925 system similar to the ful additions to confirm common proper motion. ones obtained for a few similar companions in Astrometric errors were estimated to be at the the planetary-mass regime by Ginski et al. 2014. ∼0′′. 03 level for F2 and GMOS-S data and ∼0′′. 1 for These authors find that fitted orbits suggest that SIMON imaging. Astrometric measurements are distant companions’ motion is consistent with ec- shown in Figure 4. The χ2 for the co-moving case centric orbits; whether this holds for the J0219– is 5.9 for 8 degrees of freedom. The co-moving case 3925 system remains to be determined. is equivalent to a 0.9−σ event in a Gaussian distri- 4.5. Model Fitting with Spectroscopy and bution while the background object model would Photometry correspond to a 6.0 − σ event. While this demon- strates that J0219–3925B is comoving to within To estimate fundamental parameters of mass, astrometric uncertainty, any interlopers would be effective temperature, gravity, and radius for both an L dwarf at roughly the distance of J0219–3925 J0219–3925 and J0219–3925B we used two dis- with a significant proper motion that could, con- tinct approaches with the same set of theoretical ceivably, match that of J0219–3925 within astro- models. First, we constrained the bulk properties metric uncertainties. The strongest argument in of J0219–3925A and J0219–3925B (mass, effec- favour of the two objects forming a physical pair tive temperature, surface gravity, radius and lumi- arrises from the relative rarity of field L dwarfs per nosity) by comparing the absolute magnitudes in sky surface unit. each near-infrared bandpass with BT-Settl mod- Finding a low-gravity L dwarf within 4′′ of an els2 (CIFIST 2011 opacities; Allard 2014) at 30 unrelated young M star is very unlikely. Consid- and 40 Myr. Absolute magnitudes were estimated ering that we started with a sample of 300 young from the kinematic distance; uncertainties in the stars, the area within a 2 − 6′′ annulus around kinematic distance were assumed to be 7% (see these stars covers 5.6 × 10−8 of the entire celes- tial sphere. With an L dwarf spatial density of 2https://phoenix.ens-lyon.fr/Grids/BT-Settl/CIFIST2011/

8 Fig. 3.— Spectral indices as defined by Allers & Liu 2013 for J0219–3925 and J0219–3925B, intermediate (INT-G or β) and very-low gravity (VL-G or γ) M and L dwarfs, the field sequence (thick, blue line) and its scatter (blue shaded region). The dotted line represents the delimitation between INT-G and VL-G regimes. Spectral types were offset by small (< 0.15) random subtypes so that vertical error bars can be distinguished. For all indices, J0219–3925B falls outside the enveloppe of field objects, clearly highlighting its low gravity. Four indices track both metallicity and surface gravity trends (KIJ , FeHJ , H-cont and FeHz); J0219–3925B does not show clear signs of peculiar metallicity, following the general trends of very-low gravity members. The M6 γ J0219–3925 falls in a part of the diagram where NIR low-gravity indices are less efficient than for its L4 γ companion. Alkali line equivalent widths are systematically lower than field objects and consistent with very-low gravity objects. Individual objects were drawn from Allers & Liu 2013 and Manjavacas et al. 2014.

9 subsection 4.1), leading to a 0.14 mag uncertainty on the absolute magnitudes. Table 3 compiles the value derived for each photometric bandpass, and the mean value for all three bandpasses is used as the best estimate. Upper and lower bounds are av- eraged for this best estimate, but not divided by the square root of the number of measurements as these are correlated (i.e., same age assumption, same uncertainty on distance). Overall, the mass 177 176 estimate range of 12–15MJup sets the companion 190 175 at the brown dwarf/planet regime limit. Uncer- 174 tainties for log g values are small (0.02 and 0.06

185 PA (degree) 173 respectively) as the surface gravity varies very lit- 172 2013 2014 tle with effective temperature for these relevant 180 Year masses and the main contribution to this uncer- PA (degree) tainty arrises from the uncertainty on the age of 175 the system. The relative uncertainty on the mass ∼ 170 ratio (q) is smaller ( 6 %) than the relative un- certainty on either component’s mass (∼ 10%) as 5.5 4.05 4.00 the derived masses for both components correlate 3.95 through the distance and age estimates. 3.90 5.0 3.85 The second approach to constrain the proper-

Separation (arcsec) 3.80 2 2013 2014 ties of J0219–3925B has been to perform a χ Year 4.5 fit between the observed and theoretical spectra in 3 individual bandpasses (Y + J, H and Ks;

Separation (arcsec) respectively 1.00 − 1.33 µm, 1.45 − 1.81 µm and 4.0 1.95 − 2.40µm). For each bandpass, spectra were normalized over part of the domain (horizontal 2000 2005 2010 2015 lines in Figure 5). By performing this normal- Year ization, we assume no prior knowledge of distance and . The spectral fitting anal- Fig. 4.— Position angle and separation for the ysis has been performed by steps of 0.5dex in 2MASS (1999 July 27), GMOS i-band (2012 log g between 3.5 and 5.5, and over the 1500K Novembre 2), F2 J-band (2013 Octobre 28, 2014 to 1800 K domain. Models at intermediate grav- Septembre 4) and SIMON J-band (2013 Novem- ity (4.5) better fit the SED. Within the H band bre 5) imaging. PA and separation are constant (middle columns), the higher-gravity (5.5) models to within astrometric uncertainties. Insets in each show the distinctive flattening of the SED, which panel shows the astrometric measurements ob- is the hallmark of old, field, L dwarfs. Within tained since 2012. Dashed line shows the mean PA the K band (right), there is a clear shift of the and separation, while the continuous line shows SED peak from ∼ 2.1 µm to ∼ 2.25 µm between the expected values for a distant background ob- log g = 5.5 and log g = 3.5, for all temperatures, ject. with 2M0219–3925B being intermediate between these scenarios. For Y + J and K, the best-fitting model has a temperature of 1700K and log g = 4.5. The value derived for H is only marginally dif- ferent with Teff = 1600K and log g = 4.0. These values are in very good agreement with those de- rived from photometry alone (see Table 3), with Teff = 1683 ± 43 K and log g =4.24±0.04. Overall, the mass of J0219–3925B falls squarely

10 Table 3: Constraints on properties from models. J0219–3925A J0219–3925B

Mass (MJ ) 114 ± 13 MJup 13.0 ± 0.7 MJup Mass (MH ) 108 ± 11 MJup 13.9 ± 1.1 MJup Mass (MK ) 115 ± 13 MJup 14.8 ± 1.6 MJup Mass(mean) 113 ± 12 MJup 13.9 ± 1.1 MJup

q (MJ ) 0.113 ± 0.007 q (MH ) 0.128 ± 0.006 q (MK ) 0.127 ± 0.007 q (mean) 0.123 ± 0.006

Teff (MJ ) 3070 ± 73K 1615 ± 41K Teff (MH ) 3047 ± 84K 1686 ± 43K Teff (MK ) 3074 ± 72K 1746 ± 49K Teff (mean) 3064 ± 76K 1683 ± 43K

log Luminosity (MJ ) −2.22 ± 0.06L⊙ −3.92 ± 0.03L⊙ log Luminosity (MH ) −2.26 ± 0.06L⊙ −3.84 ± 0.05L⊙ log Luminosity (MK ) −2.22 ± 0.06L⊙ −3.76 ± 0.06L⊙ log Luminosity (mean) −2.23 ± 0.06L⊙ −3.84 ± 0.05L⊙ −2 −2 log g (MJ ) 4.59 ± 0.06cms 4.23 ± 0.02cms −2 −2 log g (MH ) 4.59 ± 0.06cms 4.24 ± 0.04cms −2 −2 log g (MK ) 4.59 ± 0.06cms 4.25 ± 0.06cms log g (mean) 4.59 ± 0.06cms−2 4.24 ± 0.04cms−2

Deuterium (MJ ) 0 0.77 ± 0.06 Deuterium (MH ) 0 0.68 ± 0.07 Deuterium (MK ) 0 0.61 ± 0.09 Deuterium (mean) 0 0.69 ± 0.07

Radius (MJ ) 2.75 ± 0.14 RJup 1.41 ± 0.02 RJup Radius (MH ) 2.68 ± 0.12 RJup 1.44 ± 0.04 RJup Radius (MK ) 2.76 ± 0.14 RJup 1.46 ± 0.04 RJup Radius (mean) 2.73 ± 0.13 RJup 1.44 ± 0.03 RJup

at the upper limit of the International Astro- cation varies by ∼1 MJup depending on atmo- nomical Union definition for an – con- sphere models (Saumon & Marley 2008). The ex- sisting of an object with a true mass below the act nomenclature for such an object is still to be limiting mass for thermonuclear fusion of deu- properly defined, and it joins a number of other ob- terium – and is in orbit around a star, indeed jects such as J0103–5515(AB)b and J0122–2439B J0219–3925 has a mass estimate above the hy- (Delorme et al. 2013; Bowler et al. 2013) at the drogen burning limit for plausible ages of THA. upper-limit of planethood. As the J0219–3925B Evolution models predict that J0219–3925B will is expected to have burned some of its deuterium have retained ∼70 % of its initial deuterium by and formally lies just above the deuterium-burning 40 Myr. As it is expected to have partially burned limit, we use the ”B” designation for stellar and its deuterium, and considering its brightness, it brown dwarf companions rather than the ”b” in would constitue a good target to spectroscopically usage for planetary companions even though it is test the brown dwarf/planet boundary, that is predicted to be slightly less massive than objects expected to be moderately metallicity-dependent initially described as planetary companions (e.g., (Spiegel et al. 2011) and its exact predicted lo- AB Pictoris b).

11 Fig. 5.— Comparison between 2M0219–3925B (black) and BT-Settl models (red, green and blue) in the Y +J, H and K spectral regions. To highlight shape differences in SED of individual photometric bandpasses, we show all models normalized to a common wavelength interval (shown as a thick horizontal line in each plot). For the sake of clarity, only log g values of 3.5, 4.5 and 5.5 and temperatures from Teff = 1600K to 1800 K are plotted.

5. DISCUSSION ing energy, with a total mass ∼3 times larger (∼ 40 MJup versus ∼ 120 MJup), but a physical Figure 6 illustrates the position of J0219– separation that is also about three times larger − 3925 B in the J K color-magnitude diagram (>55 versus >160AU). It also comes close to compared to field ultracool dwarfs and planetary the J0103-5515(AB)b system, which consists of mass objects. J0219–3925B follows the overall a 12 − 14 MJup companion to a binary mid-M trend of planetary-mass companions in being red- (Delorme et al. 2013). We can rule-out the pos- der by about 0.5 mag than field ultracool dwarfs sibility that J0219–3925 is a triple analogous to of similar MK . J0103-5515(AB)b. We only have seeing-limited With a mass ratio q = 0.122 ± 0.006, the observations of the system, so a hierarchical sys- J0219–3925 system is similar to a heavier version tem with an inner component tighter than ∼0′′. 5 of 2MASSW J1207334-393254 (Chauvin et al. would not be resolved with the dataset at hands. 2005a), consisting of a 4 − 6 MJup planet around a The best constraints on the presence of an in- − − 25 45 MJup brown dwarf (mass ratio 0.13 0.16). ner binary comes from the MJ , MH and MKs With a separation of > 55AU, J1207-3932 system derived from absolute magnitude versus spectral comes very close to J0219–3925 in terms of bind- type relations for young field dwarfs. These rela-

12 Fig. 6.— Color-magnitude plot of field dwarfs, low-gravity and directly imaged companions. J0219–3925B is redder than typical field L dwarfs, and falls within the sequence of planetary-mass companions.

tions predict contrast ratios respectively of 4.36, expect considering their respective spectral types 3.78, 3.31 mag (Gagn´eet al., submitted to ApJ) (see Figure 17 in Biller et al. 2013). As shown for single M6 γ and L4 γ components, and these in Figure 2, right panel, J0219–3925B displays values are in close agreement with the observed slightly deeper water bands, especially around contrasts of ∆J = 4.2 ± 0.1, ∆H = 3.8 ± 0.1 1.5 µm and 1.95 µm and a deeper CO bandhead and ∆Ks =3.4 ± 0.1. We can therefore conclude longward of 2.29 µm, consistent with a later spec- that neither J0219–3925A nor J0219–3925B is an tral type. This brightness difference corresponds equal luminosity binary. We cannot rule-out that to a mass difference of ∼1 MJup between the two either object is itself a high-contrast (> 1 mag) objects and a comparative study could be used binary. to better constrain the deuterium burning limit J0219–3925B also shares various similarities through high resolution spectroscopy. with AB Pictoris b (Chauvin et al. 2005b). Both Figure 7 shows the host mass versus mass ratio objects are companions to Tucana-Horologium for imaged planetary and low-mass brown dwarf members and therefore share a common age. companions. Interestingly, the J0219–3925 sys- AB Pictoris b as a slightly earlier spectral type tem falls in a relative gap among known systems (L0.5 ± 0.5) and ∼0.4 mag brighter in both J and in that diagram. Known systems hosting a low- Ks (Biller et al. 2013). The brightness difference mass secondary (< 40 MJup) either have near- between the two is consistent with what would be equal mass; many of these systems have been

13 identified as near-equal luminosity field brown ratio of ∆J ∼ 8 and an effective temperature dwarfs or have a much smaller q values (typically of ∼ 600 K while at 5 Gyr, it will have a con- q < 2%) and have been uncovered with other trast of ∆J ∼ 10 and an effective temperature observing techniques. Efficient searches for near- of ∼ 370K (Beichman et al. 2010). At these mag- equal luminosity sub-stellar binaries have been nitudes and temperatures, J0219–3925B will re- largely performed with HST (e.g., Burgasser et al. spectively have spectral types of T8.5 and Y0 2006) and laser guide star adaptive-optics imag- (Dupuy & Liu 2012; Marsh et al. 2013). Such ing (e.g., Liu et al. 2012) while low-q binaries companions at separations of a few arcseconds have largely been identified by other techniques around nearby mid-M dwarfs could easily have such as microlensing, transit or radial velocity. been overlooked by current brown dwarf searches Wide-field imaging surveys have also uncovered a using WISE (Wright et al. 2010) or seeing-limited few tens of wide companions to field stars (e.g., near-infrared observations due to the far wings of Baron et al. 2015, Deacon et al. 2014 and refer- the central star’s point-spread function. GAIA3 ences compiled therein); many of these have mass astrometric measurements will not constrain the ratios comparable to that of J0219–3925, but occurence of similar systems in the solar neigh- with significantly more massive components. The bourhood; for a face-on circular orbit and a dis- two companions uncovered that come closest to tance of 10pc, the host star in a system simi- J0219–3925 are LP261-75 and Wolf 940. LP261- lar to J0219–3925 will display an astrometric ac- 75AB consists of a young M4.5/L6 binary at a celeration of ∼ 1.8 µas/yr2, below the detection projected separation of 450AU (Burgasser et al. threshold for this mission. The GAIA mission may 2005; Reid & Walkowicz 2006). LP261-75 does nevertheless uncover similar systems in young as- not match the kinematic properties of young mov- sociations through their common proper motion. ing groups included in the BANYAN II tool, but The best prospect to find Gyr-old siblings of the its primary has chromospheric activity levels con- J0219–3925 system is with the use of very deep sistent with an age of 100-200Myr. This youth of near-infrared imaging, either under good seeing the system leads to a low mass estimate for the and proper point-spread function subtraction, or secondary of 15−30 MJup. Wolf 940 AB consists of with laser-guide star adaptive optics. an M4+T8.5 binary with a projected separation of Weak constraints can be set on the occurence 400AU. The system has an age of 3.5-6Gyr as de- of companions similar to J0219–3925B around M rived from the chromospheric activity of the host dwarfs for the range of separations explored here star, leading to a mass estimate of 20-32Mjup, (100−5000AU). The PALMS survey (Bowler et al. making it a close match the LP261-75 system 2015) provides the largest sample to assess the albeit at an older age. abundance of analogs to J0219–3925B, although While pairs similar to J0219–3925 may be in- the separation range probed with their adaptive herently rare, a relatively straightforward obser- optics observations only partially overlaps with vation bias could explain the fact that similar the range of interest here. They set a < 10% upper systems have been overlooked. Hosts with spec- limit on the occurence of planets between 6 and tral types as late as that of J0219–3925A are 200 AU and < 50% limit for 1.8 − 570 AU (COND in general too faint at optical wavelengths to atmosphere models, circular orbits and 95% con- close an adaptive-optics loop on, and are there- fidence level). The discovery of a single object at fore under-represented in planet-search surveys. the planetary/brown dwarf limit in our sample is Furthermore, until very recently, very few nearby therefore well within the constraints set by the (< 50 pc) young stars that late were known, and PALMS survey. Our survey included stars with most comparable objects had been found in sig- different levels of confirmation regarding their age nificantly more distant open clusters, making the drawn from different sources, so deriving clean search of faint companions even more challeng- statistical constraints on the abundance of com- ing. While companions similar to J0219–3925B panions similar to J0219–3925B is non-trivial and may exist around very nearby M dwarfs, the con- beyond the scope of this paper. J0219–3925 was trast ratio increases significantly with age. At an age of 1 Gyr the pair would have a contrast 3http://sci.esa.int/gaia/

14 drawn from the BASS sample of late-type objects Allers, K. N., & Liu, M. C. 2013, ApJ, 772, 79 (>M4). We observed 67 high-probability BASS candidates and 13 low-probability ones (see de- Baraffe, I., Chabrier, G., Allard, F., & Hauschildt, tails Gagn´eet al. 2015); the absence of any further P. H. 1998, A&A, 337, 403 − ′′ candidate in the 2 6 separation range suggests Baron, F., et al. 2015, ApJ, 802, 37 that objects similar to J0219–3925B are relatively rare around M dwarfs, with an occurence rate of Beichman, C. A., et al. 2010, PASP, 122, 162 < 6.8% at the 95% confidence level. Biller, B. A., et al. 2013, ApJ, 777, 160 Acknowledgments Binks, A. S., & Jeffries, R. D. 2014, MNRAS, 438, The authors thank Noel Richardson for thought- L11 ful discussions regarding the characterization of Bonnefoy, M., Chauvin, G., Lagrange, A.-M., the J0219–3925 system. This paper includes data Rojo, P., Allard, F., Pinte, C., Dumas, C., & gathered with the 6.5 meter Magellan Telescopes Homeier, D. 2014, A&A, 562, A127 located at Las Campanas Observatory, Chile. Based on observations obtained at the Gemini Boss, A. P. 1997, Science, 276, 1836 Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., Bowler, B. P., Liu, M. C., Shkolnik, E. L., & under a cooperative agreement with the NSF on Dupuy, T. J. 2013, ApJ, 774, 55 behalf of the Gemini partnership: the National Bowler, B. P., Liu, M. C., Shkolnik, E. L., & Science Foundation (United States), the National Tamura, M. 2015, ApJS, 216, 7 Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Min- Brandt, T. D., et al. 2014, ApJ, 794, 159 ist´erio da Ciˆencia, Tecnologia e Inova¸c˜ao (Brazil) and Ministerio de Ciencia, Tecnolog´ıae Innovaci´on Burgasser, A. J. B., Kirkpatrick, J. D. & Productiva (Argentina). This publication makes Lowrance, P. J. 2005, ApJ, 129, 2849 use of data products from the Two Micron All Burgasser, A. J. B., et al. 2011, ApJS, 166, 585 Sky Survey, which is a joint project of the Univer- sity of Massachusetts and the Infrared Processing Burningham, B., et al. 2011, MNRAS, 395, 1237 and Analysis Center/California Institute of Tech- nology, funded by the National Aeronautics and Burningham, B., et al. 2011, MNRAS, 414, 3590 Space Administration and the National Science Cameron, A. G. W. 1978, M&P, 18, 5 Foundation. The Digitized Sky Surveys were pro- duced at the Space Telescope Science Institute Chauvin, G., Lagrange, A.-M., Dumas, C., Zuck- under U.S. Government grant NAG W-2166. The erman, B., Mouillet, D., Song, I., Beuzit, J.-L., images of these surveys are based on photographic & Lowrance, P. 2005a, A&A, 438, L25 data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Tele- Chauvin, G., et al. 2005b, A&A, 438, L29 scope. The plates were processed into the present Cruz, K., & N´u˜nez, A. 2007, in Cool Stars 17, compressed digital form with the permission of Poster Presentation these institutions. Cruz, K. L., Kirkpatrick, J. D., & Burgasser, A. J. 2009, AJ, 137, 3345 REFERENCES Cruz, K. L., et al. 2007, AJ, 133, 439 Alibert, Y., Mordasini, C., Benz, W. & Winisdo- erffer, C. 2005, A&A, 434, 343 Cutri, R. M., et al. 2013, VizieR Online Data Cat- alog, 2328, 0 Allard, F. 2014, in IAU Symposium, Vol. 299, IAU Symposium, ed. M. Booth, B. C. Matthews, & D’Antona, F., & Mazzitelli, I. 1997, Mem. Soc. As- J. R. Graham, 271–272 tron. Italiana, 68, 807

15 1.00 2M 0746+20 b

2M 2140+16 b

FU Tau b UScoCTIO 108 b Secondary at stellar/BD limit 2M1207 b 30Myr40Myr Wolf 940 B 0.10 LP 261−75 B Secondary at BD/planet limit ) 1 /m 2

FW Tau b q (m stellar/BD limit Primary at

0.01 J0219−3915 system Imaging Radial velocity Microlensing Transit SLoWPoKES

0.1

Host mass (MSun)

Fig. 7.— Host mass versus mass ratio for substellar companions detected through direct imaging (black), radial-velocity (blue), microlensing (green) or transit (orange). Also included is the very large sample of binaries including an cool dwarf from the SLoWPoKES survey (Dhital et al. 2010). Imaged binaries with orbital separations larger than 100 AU are circled. Dashed lines indicate the notional 13 MJup BD/planet limit for companions and the brown dwarf/stellar limit for both hosts and companions and selected systems are labelled. Some hosts (e.g., 2M 0746+20; Konopacky et al. 2010) are themselves near-equal mass binaries; the total mass of the central binary is given. The position of the J0219–3925 system for ages of 30 and 40Myr is shown. The J0219–3925 system falls in an empty part of the diagram, intermediate in properties between near-equal mass binaries such as 2M0746+20 and 2M2140+16 (Konopacky et al. 2010) and planets uncovered through radial velocity measurements and imaging of young systems. Most systems close to the stellar/substellar limit are L dwarfs companions to field stars found through wide-field surveys. System parameters were drawn from the Extrasolar Planets Encyclopedia, Deacon et al. 2014, Baron et al. 2015 and Konopacky et al. 2010.

Deacon, N. R., et al. 2014, ApJ, 792, 119 tronomical Society of the Pacific Conference Se- ries, Vol. 195, Imaging the Universe in Three Delorme, P., et al. 2013, A&A, 553, L5 Dimensions, ed. W. van Breugel & J. Bland- DENIS Consortium. 2005, yCat, 2263, 0 Hawthorn, 548 Dhital, S., West, A. A., Stassun, K. G. & Bochan- Dupuy, T. J., & Liu, M. C. 2012, ApJS, 201, 19 ski, J. J. 2010, ApJ, 139, 2566 Epchtein, N., et al. 1999, VizieR Online Data Cat- Doyon, R., Nadeau, D., & Vall´ee, P. 2000, in As- alog, 2240, 0

16 Feiden, G. A., & Chaboyer, B. 2013, ApJ, 779, 183 Malo, L., Doyon, R., Lafreni`ere, D., Artigau, E.,´ Gagn´e, J., Baron, F., & Riedel, A. 2013, ApJ, Follert, R., et al. 2015, Proc. SPIE, 9147, 19 762, 88 Gagn´e, J., Faherty, J. K., Cruz, K., Lafreni`ere, Marois, C., Macintosh, B., Barman, T., Zucker- ´ D., Doyon, R., Malo, L., & Artigau, E. 2014a, man, B., Song, I., Patience, J., Lafreni`ere, D., ApJ, 785, L14 & Doyon, R. 2008, Science, 322, 1348 ´ Gagn´e, J., Lafreni`ere, D., Doyon, R., Artigau, E., Marois, C., Zuckerman, B., Konopacky, Q. M., Malo, L., Robert, J., & Nadeau, D. 2014b, ApJ, Macintosh, B., & Barman, T. 2010, Nature, 792, L17 468, 1080 Gagn´e, J., Lafreni`ere, D., Doyon, R., Malo, L., & Marsh, K. A., Wright, E. L., Kirkpatrick, J. D., ´ Artigau, E. 2014c, ApJ, 783, 121 Gelino, C. R., Cushing, M. C., Griffith, R. L., Skrutskie, M. F., & Eisenhardt, P. R. 2013, —. 2015, ApJ, 798, 73 ApJ, 762, 119 Ginski, C., Schmidt, T. O. B., Mugrauer, M., McLean, I. S., McGovern, M. R., Burgasser, A. J., Neuh¨auser, R., Vogt, N., Errmann, R., & Kirkpatrick, J. D., Prato, L., & Kim, S. S. 2003, Berndt, A. 2014, MNRAS, 444, 2280 ApJ, 596, 561 Girard, T. M., et al. 2011, AJ, 142, 15 Mo´or, A., Szab´o, G. M., Kiss, L. L., Kiss, C., Goldman, B., Marsat, S., Henning, T., Clemens, Abrah´am,´ P., Szul´agyi, J., K´osp´al, A.,´ & Szalai, C., & Greiner, J. 2010, MNRAS, 405, 1140 T. 2013, MNRAS, 435, 1376 Kalas, P., et al. 2008, Science, 322, 1345 Naud, M.-E., et al. 2014, ApJ, 787, 5 Kirkpatrick, J. D. 2005, ARA&A, 43, 195 Padoan, P., & Nordlund, A.˚ 2002, ApJ, 576, 870 Kirkpatrick, J. D., Barman, T. S., Burgasser, Pollack, J. B., Hubickyj, O., Bodenheimer, P., A. J., McGovern, M. R., McLean, I. S., Tin- Lissauer, J. J., Podolak, M. & Greenzweig, Y. ney, C. G., & Lowrance, P. J. 2006, ApJ, 639, 1996, Icarus, 124, 62 1120 Reid, I. N., & Walkowicz, L. M. 2006, PASP, 118, Kiss, L. L., et al. 2011, MNRAS, 411, 117 671 Konopacky, Q. M., Ghez, A. M., Barman, T. S., Rice, E. L., Barman, T., Mclean, I. S., Prato, L., Rice, E. L., Bailey, III, J. I., White, R. J., & Kirkpatrick, J. D. 2010, ApJS, 186, 63 McLean, I. S., & Duchˆene, G. 2010, ApJ, 711, Rodriguez, D. R., Zuckerman, B., Kastner, J. H., 1087 Bessell, M. S., Faherty, J. K., & Murphy, S. J. Kraus, A. L., Shkolnik, E. L., Allers, K. N., & Liu, 2013, ApJ, 774, 101 M. C. 2014, AJ, 147, 146 Saumon, D., & Marley, M. S. 2008, ApJ, 689, 1327 Lagrange, A.-M., et al. 2010, Science, 329, 57 Simcoe, R. A., et al. 2013, PASP, 125, 270 Liu, M.-C., et al. 2012, ApJ, 647, 1393 Skrutskie, M. F., et al. 2006, AJ, 131, 1163 Manjavacas, E., et al. 2014, A&A, 564, 55 Song, I., Bessell, M. S., & Zuckerman, B. 2002, ApJ, 581, L43 Malo, L., Artigau, E.,´ Doyon, R., Lafreni`ere, D., Albert, L., & Gagn´e, J. 2014a, ApJ, 788, 81 Spiegel, D. S., Burrows, A., & Milsom, J. A. 2011, ApJ, 727, 57 Malo, L., Doyon, R., Feiden, G. A., Albert, L., Lafreni`ere, D., Artigau, E.,´ Gagn´e, J., & Riedel, Torres, C. A. O., da Silva, L., Quast, G. R., de la A. 2014b, ApJ, 792, 37 Reza, R., & Jilinski, E. 2000, AJ, 120, 1410

17 Torres, C. A. O., Quast, G. R., Melo, C. H. F., & Sterzik, M. F. 2008, Young Nearby Loose Associations, ed. B. Reipurth, 757 Veras, D., Crepp, J. R., & Ford, E. B. 2009, ApJ, 696, 1600

Vorobyov, E. I. 2013, A&A, 552, A129 Wright, E. L., et al. 2010, AJ, 140, 1868 Yee, J. C., & Jensen, E. L. N. 2010, ApJ, 711, 303 Zacharias, N., Monet, D. G., Levine, S. E., Urban, S. E., Gaume, R., & Wycoff, G. L. 2005, VizieR Online Data Catalog, 1297, 0 Zuckerman, B., & Song, I. 2004, ARA&A, 42, 685 Zuckerman, B., Song, I., & Webb, R. A. 2001, ApJ, 559, 388 Zuckerman, B., & Webb, R. A. 2000, ApJ, 535, 959

A This 2-column preprint was prepared with the AAS L TEX macros v5.2.

18