Circum-Planet and Circum- Secondary Disk Eclipses

Circum-planet and Circum- secondary Disk Eclipses

- Eric Mamajek, Mark Pecaut

(discovers of J1407 event) Alice Quillen - Erin Sco, Fred Moolekamp

Vmag (U Rochester) (eclipse modeling) in collaboraon - Ma Kenworthy, Andrew Collier Cameron & Neil with  Parley (photometry and period analysis)

DAYS  Objects with long deep eclipses (primary only) Interpreted as circum-secondary disks Eclipse Eclipse Depth Visible IR Secondary length period (mags) Object excess EE Cep 30-60 days 5.6 years 0.6-2.1 B5e ? Yes ε Aurigae 2 years 27.1 years 0.8 F0 I? B? Yes OGLE-LMC- 2 days 13.35 days 0.5 B2 ? ? ECL-17782 J1407 ~60 days > 2.3 years to 4 K5V ? No

ε Aur Guinan& mag

V DeWarf ‘02

OGLE-LMC-ECL-17782 from OGLEIII; Graczyk et al.‘11 mag I

phase EE-Cep

Images from Galan et al. 2009 Sizes of things • Radius of Jupiter RJ=71,000km 8 • Semi-major axis Jupiter aJ=5.2 AU = 7.8x10 km 1 3 • Hill Radius of Jupiter r = 0.35 AU Mp H rH = ap = 5x107km 3M ∗ • Callisto’s semi-major axis around Jupiter 6 ac= 1.9x10 km = 26.76 RJ = 0.036 rH Probability of a favorable orientaon giving eclipses or transits over an orbit 2πra r f 2 ≈ 4πa ∼ 2a Disk out to the Hill radius f ~0.02 Disk out to Callisto f ~ 1x10-3 For an exo Jupiter transit f ~ 4x10-8 Length of eclipses

ξ= disk radius in units of Hill radius

μ=Mp/M* planet or binary mass rao Fracon of orbit in eclipse f ~ 2r/2πa ~ 0.2 ξ μ1/3 gives us a limit on mass of secondary. If f is large then a circumbinary disk is more likely (e.g., KH 15D) Eclipse length 1 1 3 3 3 ξ Mp M − ap 2 teclipse 17 days ∗ ∼ 0.2 mJ M 5AU ⊙ Anything that ﬁlls a p of iceberg modest fracon of a

Hill radius is huge. J1407

• Probability of having orientaons suitable for eclipses is not low (compared to planet transits). • Assume 5-10% of systems have exo-Jupiters with period distribuon ﬂat in log semi-major axis. Each planet has a circumplanetary disk ﬁlling some fracon of its Hill radius. Obliquity/thickness distribuons. • Observe a sample of stars photometricaly for 10 years (so can count all with periods within this)  a few in 104 stars should exhibit circumplanetary disk eclipses. • Only naked eye visible eclipsing disks now known. • Deep long eclipses should be seen. The real problem: Lifemes • Disk lifemes are short. Circumsecondary disks can only be seen clearly in eclipse aer the primary’s disk is gone. • The number of mixed young binary systems (one star with disk and other without) is poorly constrained. If the secondary is low mass or/and the disk contains a hole in it, then these could have been missed from IR surveys of binaries in clusters (Prato, Weinberger, McCabe, DuChene). Binaries in mixed state (one object with disk, other not) are common. Circumplanetary disk sizes and lifemes • Lifemes of circumplanetary disks esmated from theorecal formaon models (e.g., Canup, Ward, Alibert, Estrada, Mosquiera) in the context of Jovian satellite formaon. Models postulate a circumJovian excreon disk with up to 10 A compilaon of centrifugal million year lifeme. disk radius esmates for the • Circumplanetary disk lifemes proto-Jovian disk (Ward & may be longer in outer solar Canup 2010) systems, (e.g. possibly relevant Disk radii in Hill radii for interpretaon of Fomalhaut ξ~0.1-0.3 b) but periods get long! Worst case

• 10 year photometric survey of many stars in the Milky Way disk. • Constant star formaon rate for 1010 years • Disk lifemes 107 years (or correct for your favorite value) • Probably of a star being young enough to host a circumplanetary disk is ~10-3  Only need to survey ~107 stars to ﬁnd a few disk eclipses (either circumsecondary or circumplanetary) if you pick young stars you don’t have to survey as many … Discovery of J1407’s eclipse

Program of searching for and characterizing young stars in moving groups (Mamajek and Pecaut)

Cross correlate kinemac data with X- ray catalogs. Moving groups cover degrees on the sky. Spectroscopic and photometric follow up of a few hundred low mass star associaon candidates. The star HR diagram K5 IV(e) Li Spectral Age 16 Myr, energy Mass 0.9 M distribuon member of the 16 Myr-old Upper Centaurus-Lupus No IR excess subgroup of Sco-Cen at a distance of 128±13 pc. PPMX_J140747.9-394542 1SWASP_J140747.93-394542.6 2MASS_J14074792-3945427; Signs of youth: moving group membership, Li rich (0.4Å abs), -3.2 saturated X-ray ﬂux (LX/Lbol~10 ), rapid rotaon period 3.2 days, Hα (0.2Å emission) No IR excess. Limits placed on luminosity of a secondary. Light Curves

J1407

Eclipse seen in two diﬀerent all sky surveys. Super Wasp (Super Wide Angle Search for Planets; Pollacco et al. 06) ASAS (All Sky Automated Survey Pojmanski et al 02) Nearby stars on the sky did not display an eclipse.

days Nightly averages

Gaps

Rings J1407

days ASAS Over 9 years of observaons

Period must be longer than a few years Could be longer than 7 years Dip in 2001 might be an eclipse? J1407 Probability of a few low points is not real small On hourly mescales

beginning of eclipse end of eclipse

Fine structure might imply a very thin disk with lots of structure, like Saturn’s rings Few hours/30 days gives disk aspect rao of h/r~0.01 Is this structure real or are there pipeline problems with Super WASP? Limits …. • Fracon of period spent in eclipse < 6% This implies that the secondary mass -3 m2 < 20 MJ ξ – Could be a brown dwarf secondary with a disk ﬁlling its Roche radius – Could be an M star with a smaller disk – The longer the system seen without eclipses, the lower the mass limit on the secondary (assuming that the disk host is a secondary). • Eclipse length implies that the disk radius is ~ 0.08 AU Long length of eclipse implies a big disk Disk size esmate is only weakly dependent on period. Eclipse models and Gap opening objects

Impact parameter leads to asymmetry in eclipse curve Non unique eclipse model by Erin and Fred!

1 3 If gaps in light curve interpreted in tgap msatellite terms of gap opening objects then their teclipse ∼ 3m2 mass is of order 10-3 of secondary Gap opening objects likely prey small Summary • Discovery of a long deep eclipse on a pre-main sequence solar type star. Similar to EE Cep (but beer as nearer and not involving a B star). • Dense, large, thin disk with rings/gaps. Secondary is probably a low mass star hosng a forming planetary system. • We don’t know the eclipse period • We don’t have any radial velocity informaon • Eclipse searches can tell us about lifemes of late stage disks, and substructure in them in the epoch of planet/ satellite formaon. • Disk eclipses will be found in photometric surveys. – A crude esmate (with assumpons on obliquity, size, mass and period distribuons …), is a few per 104 stars surveyed for 10 years for stars in correct age range or a few per 107 stars mixed ages