DOCSLIB.ORG

Spatially Resolved Spectroscopy of the Exoplanet HR 8799 C∗

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Spatially Resolved Spectroscopy of the Exoplanet HR 8799 C∗ Spatially resolved spectroscopy of the exoplanet HR 8799 c∗ M. Janson1,4, C. Bergfors2, M. Goto2, W. Brandner2, D. Lafreni`ere3 [email protected] ABSTRACT HR 8799 is a multi-planet system detected in direct imaging, with three companions known so far. Here, we present spatially resolved VLT/NACO 3.88–4.10 µm spectroscopy of the middle planet, HR 8799 c, which has an estimated mass of ∼10 MJup, temperature of ∼1100 K and projected separation of 38 AU. The spectrum shows some differences in the continuum from existing theoretical models, particularly longwards of 4µm, implying that detailed cloud structure or non-equilibrium conditions may play an important role in the physics of young exoplanetary atmospheres. Subject headings: planetary systems — techniques: spectroscopic 1. Introduction spectral signal from the stellar one. During the past year, several planet candi- Spectroscopy of extrasolar planets will be a key dates from direct imaging have been reported (e.g. tool towards understanding their formation and Lafreniere et al. 2008, Kalas et al. 2008, Lagrange atmospheres, and could eventually lead to identifi- et al. 2009). Of particular interest here is the cation of chemical biomarkers (e.g. Kaltenegger et HR 8799 planetary system (Marois et al. 2008), al. 2007), thus addressing the question of life else- where the three companions have been confirmed where in the universe. However, the large bright- through common proper motion, orbital motion, ness contrast and small angular separation be- and detection of thermal radiation in several pho- tween a star and planet makes such spectroscopy tometric bands. This system is in many ways rem- technologically challenging. In the special geomet- iniscent of a scaled-up version of our own Solar ric case where the orbital plane of the planet is system. HR 8799 itself is an A5 star of 1.5 M . aligned along our line of sight, a spectroscopic sig- Sun HR 8799 b, c, and d have estimated masses of 7 nal can be temporally resolved by comparing the M , 10 M , and 10 M and separations of combined star and planet light in and out of tran- Jup Jup Jup 68 AU, 38 AU and 24 AU, respectively. The mass sit or secondary eclipse. This has been successfully estimates are based on an age estimate of 60 Myr done with the Spitzer and Hubble space telescopes for HR 8799. Although much higher ages are diffi- (e.g. Grillmair et al. 2007; Swain et al. 2009). cult to exclude categorically, several age indicators However, the vast majority of exoplanets do not (such as the massive debris disk) and arguments share this fortunate geometry. For these planets, from dynamical stability mutually indicate such a it is necessary to spatially resolve the planetary young age (e.g. Reidemeister et al. 2009). Mod- eling of infrared excess by Spitzer (e.g. Chen et *Based on observations collected at the European Southern Observatory, Chile (ESO No. 084.C-0072) and al. 2009) has shown that a Kuiper-analogous de- at the Subaru telescope, which is operated by the National bris belt exists outside of HR 8799 b, and a debris Astronomical Observatory of Japan. belt analogous to the Asteroid belt exists inside of 1 University of Toronto, Toronto, Canada HR 8799 d. The planets appear to be largely co- 2 Max-Planck-Institute for Astronomy, Heidelberg, Ger- planar with an orbital plane close to face-on, and many have low eccentricities. 3University of Montreal, Montreal, Canada 4Reinhardt fellow 1 2. Observations and Data Analysis to optimize the slit alignment. A 150 second se- quence without any high-contrast technique ap- Spectroscopic runs were performed with IRCS plied showed the presence the planet, confirming at Subaru and NACO at the VLT during the sec- that HR 8799 c indeed dominates the stellar PSF ond half of 2009 with the purpose of detecting the ′ at its separation (see Fig. 1). The slit was aligned spectroscopic L -band signature of the planets, in along the star-planet axis to ensure an adequate particular HR 8799 b and c. The IRCS run was slit positioning and a good PSF characterization of aimed primarily at HR 8799 b, and proved the the star, as well as provide an optimal correction feasibility of the technique, but the thermal back- of telluric and instrumental transmission effects. ground was much higher than predicted, probably The price to pay for this is some ghost images due to dust on the image rotator or the high am- on the detector from internal reflections. Pairwise bient humidity during the run. Hence, no planet nodding with 5” nod size was applied for back- spectroscopy could be extracted from the IRCS ground subtraction. Observations were also taken data. For the NACO run, one out of four half- with a slit rotation of 180o for PSF reference sub- nights was clouded out and two had thin cirrus traction. Flat field frames were produced with the clouds. During one of the nights with cirrus, HR slit and grism in, pointing at the thermal sky. 8799 b was included in the slit. Hence, some The data reduction was performed with ded- NACO data of HR 8799 b exists, but given the icated procedures written in IDL. The flat field ambient conditions we focused mainly on getting frame reproduced the expected vertical fringes a strong detection on HR 8799 c during the rest that occur in 4 µm spectroscopy. The fringe pat- of the time. The HR 8799 c spectroscopy is the tern was constant but shifted laterally with time, topic of this Letter. so the flat frame had to be digitally shifted to The technique employed was slit spectroscopy ′ each science frame. Since doing so would elimi- in the L -band range. This choice is based on nate pixel-to-pixel variation correction on the de- the combination of facts that the star-to-planet tector, both the image and flat frames first had to contrast is more favorable there (9.5 mag for HR be corrected for such variations. This was done 8799 c, as compared to 11.6 in H-band), and that with an imaging L′-band flat which was also ac- an exceptional adaptive optics performance can quired during the night. The spectral dependency be achieved in this range (upwards of 85 % at 4 of the pixel response was negligible, and so this µm, see Janson et al. 2008). For these reasons, a correction could be done satisfactorily. The shift planet like HR 8799 c dominates the stellar PSF ′ of the spectroscopic flat was determined individu- at its angular separation. A disadvantage of L - ally for each science frame by cross-correlation of band with respect to shorter wavelengths is the the fringe pattern with minimization of the resid- higher thermal background, but previous observa- uals. The flat- and dark-corrected frames were tions had shown that this was not a major limita- pairwise subtracted to remove the thermal back- tion. The widest NACO slit of 172 mas was used, ground. The spectrum of the star was traced to which allows for the companion PSF to be entirely an absolute center using a Gaussian fit on the PSF included in the slit, and along with the high PSF core individually for each wavelength, and rela- stability, allows to ensure that PSF chromaticity tive centering was checked using cross-correlation will have a negligible effect over the relevant wave- on the core with minimization of the residuals. A length range. The spectral resolution, limited by trace was then fitted over all wavelengths with 21 the FWHM, was approximately 900. The pixel pixel median box filtering, and all spectra were scale was 27 mas/pixel. Individual integration shifted to a common center. A collapse of all the times were 5 sec, and 20 coadds per frame were frames revealed the spectrum of the planet, at the taken. After excluding bad frames, 102 frames expected position and with the expected average were used for the target characterization and 94 brightness (see Fig. 2). The short-wavelength tail for the PSF characterization, giving total integra- of the planetary spectrum interfered with a resid- tion times of 10200 sec and 9400 sec, respectively. ual ghost feature, which could not be entirely re- ′ A quick-look L -band image of the HR 8799 moved since the PSF reference frames were not system was taken in the beginning of the night taken at identical dithering positions as the sci- 2 ence frames. Hence, we count this range as being wavelength end, and likewise a significant devia- of insufficient quality and use only the > 3.88 µm tion from the model. range where the planetary spectrum is clean. Hence, there are features in the spectrum that The star and planet spectra were extracted the COND model cannot explain. Part of the using 4-pixel apertures (108 mas, close to the problem is probably dust in the atmosphere – FWHM of the PSF). The background for the COND assumes dust-free conditions. However, a planet was estimated on the corresponding flux in DUSTY model (Chabrier et al. 2000) with the the PSF reference frame, averaged over 7 neigh- same range of parameters can also not reproduce boring pixels in the wavelength direction so as not the spectrum (see Fig. 4). Models with interme- to increase the background noise. The background diate abundances of dust have also been unable residual spectrum (non-averaged over wavelength) to reproduce the full set of observed properties of was also used to estimate the error by taking the the HR 8799 planets (Marois et al. 2008). The standard deviation over 21 neighboring pixels in results therefore imply that a more detailed treat- the wavelength direction.
Load more

Recommended publications
  • Naming the Extrasolar Planets
    Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named.
    [Show full text]
  • Arxiv:1904.05358V1 [Astro-Ph.EP] 10 Apr 2019
    Draft version April 12, 2019 Typeset using LATEX default style in AASTeX62 The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10{100 AU Eric L. Nielsen,1 Robert J. De Rosa,1 Bruce Macintosh,1 Jason J. Wang,2, 3, ∗ Jean-Baptiste Ruffio,1 Eugene Chiang,3 Mark S. Marley,4 Didier Saumon,5 Dmitry Savransky,6 S. Mark Ammons,7 Vanessa P. Bailey,8 Travis Barman,9 Celia´ Blain,10 Joanna Bulger,11 Jeffrey Chilcote,1, 12 Tara Cotten,13 Ian Czekala,3, 1, y Rene Doyon,14 Gaspard Duchene^ ,3, 15 Thomas M. Esposito,3 Daniel Fabrycky,16 Michael P. Fitzgerald,17 Katherine B. Follette,18 Jonathan J. Fortney,19 Benjamin L. Gerard,20, 10 Stephen J. Goodsell,21 James R. Graham,3 Alexandra Z. Greenbaum,22 Pascale Hibon,23 Sasha Hinkley,24 Lea A. Hirsch,1 Justin Hom,25 Li-Wei Hung,26 Rebekah Ilene Dawson,27 Patrick Ingraham,28 Paul Kalas,3, 29 Quinn Konopacky,30 James E. Larkin,17 Eve J. Lee,31 Jonathan W. Lin,3 Jer´ ome^ Maire,30 Franck Marchis,29 Christian Marois,10, 20 Stanimir Metchev,32, 33 Maxwell A. Millar-Blanchaer,8, 34 Katie M. Morzinski,35 Rebecca Oppenheimer,36 David Palmer,7 Jennifer Patience,25 Marshall Perrin,37 Lisa Poyneer,7 Laurent Pueyo,37 Roman R. Rafikov,38 Abhijith Rajan,37 Julien Rameau,14 Fredrik T. Rantakyro¨,39 Bin Ren,40 Adam C. Schneider,25 Anand Sivaramakrishnan,37 Inseok Song,13 Remi Soummer,37 Melisa Tallis,1 Sandrine Thomas,28 Kimberly Ward-Duong,25 and Schuyler Wolff41 1Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305, USA 2Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 3Department of Astronomy, University of California, Berkeley, CA 94720, USA 4NASA Ames Research Center, Mountain View, CA 94035, USA 5Los Alamos National Laboratory, P.O.
    [Show full text]
  • Correlations Between the Stellar, Planetary, and Debris Components of Exoplanet Systems Observed by Herschel⋆
    A&A 565, A15 (2014) Astronomy DOI: 10.1051/0004-6361/201323058 & c ESO 2014 Astrophysics Correlations between the stellar, planetary, and debris components of exoplanet systems observed by Herschel J. P. Marshall1,2, A. Moro-Martín3,4, C. Eiroa1, G. Kennedy5,A.Mora6, B. Sibthorpe7, J.-F. Lestrade8, J. Maldonado1,9, J. Sanz-Forcada10,M.C.Wyatt5,B.Matthews11,12,J.Horner2,13,14, B. Montesinos10,G.Bryden15, C. del Burgo16,J.S.Greaves17,R.J.Ivison18,19, G. Meeus1, G. Olofsson20, G. L. Pilbratt21, and G. J. White22,23 (Affiliations can be found after the references) Received 15 November 2013 / Accepted 6 March 2014 ABSTRACT Context. Stars form surrounded by gas- and dust-rich protoplanetary discs. Generally, these discs dissipate over a few (3–10) Myr, leaving a faint tenuous debris disc composed of second-generation dust produced by the attrition of larger bodies formed in the protoplanetary disc. Giant planets detected in radial velocity and transit surveys of main-sequence stars also form within the protoplanetary disc, whilst super-Earths now detectable may form once the gas has dissipated. Our own solar system, with its eight planets and two debris belts, is a prime example of an end state of this process. Aims. The Herschel DEBRIS, DUNES, and GT programmes observed 37 exoplanet host stars within 25 pc at 70, 100, and 160 μm with the sensitiv- ity to detect far-infrared excess emission at flux density levels only an order of magnitude greater than that of the solar system’s Edgeworth-Kuiper belt. Here we present an analysis of that sample, using it to more accurately determine the (possible) level of dust emission from these exoplanet host stars and thereafter determine the links between the various components of these exoplanetary systems through statistical analysis.
    [Show full text]
  • Worlds Apart - Finding Exoplanets
    Worlds Apart - Finding Exoplanets Illustrated Video Credit: NASA, JPL-Caltech, T. Pyle; Acknowledgement: djxatlanta Dr. Billy Teets Vanderbilt University Dyer Observatory Osher Lifelong Learning Institute Thursday, November 5, 2020 Outline • A bit of info and history about planet formation theory. • A discussion of the main exoplanet detection techniques including some of the missions and telescopes that are searching the skies. • A few examples of “notable” results. Evolution of our Thinking of the Solar System • First “accepted models” were geocentric – Ptolemy • Copernicus – heliocentric solar system • By 1800s, heliocentric model widely accepted in scientific community • 1755 – Immanuel Kant hypothesizes clouds of gas and dust • 1796 – Kant and P.-S. LaPlace both put forward the Solar Nebula Disk Theory • Today – if Solar System formed from an interstellar cloud, maybe other clouds formed planets elsewhere in the universe. Retrograde Motion - Mars Image Credits: Tunc Tezel Retrograde Motion as Explained by Ptolemy To explain retrograde, the concept of the epicycle was introduced. A planet would move on the epicycle (the smaller circle) as the epicycle went around the Earth on the deferent (the larger circle). The planet would appear to shift back and forth among the background stars. Evolution of our Thinking of the Solar System • First “accepted models” were geocentric – Ptolemy • Copernicus – heliocentric solar system • By 1800s, heliocentric model widely accepted in scientific community • 1755 – Immanuel Kant hypothesizes clouds of gas and dust • 1796 – Kant and P.-S. LaPlace both put forward the Solar Nebula Disk Theory • Today – if Solar System formed from an interstellar cloud, maybe other clouds formed planets elsewhere in the universe.
    [Show full text]
  • GEMINI PLANET IMAGER SPECTROSCOPY of the HR 8799 PLANETS C and D
    The Astrophysical Journal Letters, 794:L15 (5pp), 2014 October 10 doi:10.1088/2041-8205/794/1/L15 C 2014. The American Astronomical Society. All rights reserved. Printed in the U.S.A. GEMINI PLANET IMAGER SPECTROSCOPY OF THE HR 8799 PLANETS c AND d Patrick Ingraham1, Mark S. Marley2, Didier Saumon3, Christian Marois4, Bruce Macintosh1, Travis Barman5, Brian Bauman6, Adam Burrows7, Jeffrey K. Chilcote8, Robert J. De Rosa9,10, Daren Dillon11,Rene´ Doyon12, Jennifer Dunn4, Darren Erikson4, Michael P. Fitzgerald8, Donald Gavel11, Stephen J. Goodsell13, James R. Graham14, Markus Hartung13, Pascale Hibon13, Paul G. Kalas14, Quinn Konopacky15, James A. Larkin8, Jer´ omeˆ Maire15, Franck Marchis16, James McBride14, Max Millar-Blanchaer15, Katie M. Morzinski17,24, Andrew Norton11, Rebecca Oppenheimer18, Dave W. Palmer6, Jenny Patience9, Marshall D. Perrin19, Lisa A. Poyneer6, Laurent Pueyo19, Fredrik Rantakyro¨ 13, Naru Sadakuni13, Leslie Saddlemyer4, Dmitry Savransky20,Remi´ Soummer19, Anand Sivaramakrishnan19, Inseok Song21, Sandrine Thomas2,22, J. Kent Wallace23, Sloane J. Wiktorowicz11, and Schuyler G. Wolff19 1 Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305, USA 2 NASA Ames Research Center, Moffett Field, CA 94035, USA 3 Los Alamos National Laboratory, Los Alamos, NM 87545, USA 4 NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada 5 Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721-0092, USA 6 Lawrence Livermore National Lab,
    [Show full text]
  • Structure of Exoplanets SPECIAL FEATURE
    Structure of exoplanets SPECIAL FEATURE David S. Spiegela,1, Jonathan J. Fortneyb, and Christophe Sotinc aSchool of Natural Sciences, Astrophysics Department, Institute for Advanced Study, Princeton, NJ 08540; bDepartment of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064; and cJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 Edited by Adam S. Burrows, Princeton University, Princeton, NJ, and accepted by the Editorial Board December 4, 2013 (received for review July 24, 2013) The hundreds of exoplanets that have been discovered in the entire radius of the planet in which opacities are high enough past two decades offer a new perspective on planetary structure. that heat must be transported via convection; this region is Instead of being the archetypal examples of planets, those of our presumably well-mixed in chemical composition and specific solar system are merely possible outcomes of planetary system entropy. Some gas giants have heavy-element cores at their centers, formation and evolution, and conceivably not even especially although it is not known whether all such planets have cores. common outcomes (although this remains an open question). Gas-giant planets of roughly Jupiter’s mass occupy a special Here, we review the diverse range of interior structures that are region of the mass/radius plane. At low masses, liquid or rocky both known and speculated to exist in exoplanetary systems—from planetary objects have roughly constant density and suffer mostly degenerate objects that are more than 10× as massive as little compression from the overlying material. In such cases, 1=3 Jupiter, to intermediate-mass Neptune-like objects with large cores Rp ∝ Mp , where Rp and Mp are the planet’s radius mass.
    [Show full text]
  • First Direct Detection of an Exoplanet by Optical Interferometry Astrometry and K-Band Spectroscopy of HR 8799 E?,??
    A&A 623, L11 (2019) Astronomy https://doi.org/10.1051/0004-6361/201935253 & c S. Lacour et al. 2019 Astrophysics LETTER TO THE EDITOR First direct detection of an exoplanet by optical interferometry Astrometry and K-band spectroscopy of HR 8799 e?;?? GRAVITY Collaboration: S. Lacour1,2, M. Nowak1, J. Wang20;???, O. Pfuhl2, F. Eisenhauer2, R. Abuter8, A. Amorim6,14, N. Anugu7,22, M. Benisty5, J. P. Berger5, H. Beust5, N. Blind10, M. Bonnefoy5, H. Bonnet8, P. Bourget9, W. Brandner3, A. Buron2, C. Collin1, B. Charnay1, F. Chapron1, Y. Clénet1, V. Coudé du Foresto1, P. T. de Zeeuw2,12, C. Deen2, R. Dembet1, J. Dexter2, G. Duvert5, A. Eckart4,11, N. M. Förster Schreiber2, P. Fédou1, P. Garcia7,9,14 , R. Garcia Lopez15,3, F. Gao2, E. Gendron1, R. Genzel2,13, S. Gillessen2, P. Gordo6,14, A. Greenbaum16, M. Habibi2, X. Haubois9, F. Haußmann2, Th. Henning3, S. Hippler3, M. Horrobin4, Z. Hubert1, A. Jimenez Rosales2, L. Jocou5, S. Kendrew17,3, P. Kervella1, J. Kolb9, A.-M. Lagrange5, V. Lapeyrère1, J.-B. Le Bouquin 5, P. Léna1, M. Lippa2, R. Lenzen3, A.-L. Maire19,3, P. Mollière12, T. Ott2, T. Paumard1, K. Perraut5, G. Perrin1, L. Pueyo18, S. Rabien2, A. Ramírez9, C. Rau2, G. Rodríguez-Coira1, G. Rousset1, J. Sanchez-Bermudez21,3, S. Scheithauer3, N. Schuhler9, O. Straub1,2, C. Straubmeier4, E. Sturm2, L. J. Tacconi2, F. Vincent1, E. F. van Dishoeck2,12, S. von Fellenberg2, I. Wank4, I. Waisberg2, F. Widmann2, E. Wieprecht2, M. Wiest4, E. Wiezorrek2, J. Woillez8, S. Yazici2,4, D. Ziegler1, and G. Zins9 (Affiliations can be found after the references) Received 12 February 2019 / Accepted 28 February 2019 ABSTRACT Aims.
    [Show full text]
  • Planet Searching from Ground and Space
    Planet Searching from Ground and Space Olivier Guyon Japanese Astrobiology Center, National Institutes for Natural Sciences (NINS) Subaru Telescope, National Astronomical Observatory of Japan (NINS) University of Arizona Breakthrough Watch committee chair June 8, 2017 Perspectives on O/IR Astronomy in the Mid-2020s Outline 1. Current status of exoplanet research 2. Finding the nearest habitable planets 3. Characterizing exoplanets 4. Breakthrough Watch and Starshot initiatives 5. Subaru Telescope instrumentation, Japan/US collaboration toward TMT 6. Recommendations 1. Current Status of Exoplanet Research 1. Current Status of Exoplanet Research 3,500 confirmed planets (as of June 2017) Most identified by Jupiter two techniques: Radial Velocity with Earth ground-based telescopes Transit (most with NASA Kepler mission) Strong observational bias towards short period and high mass (lower right corner) 1. Current Status of Exoplanet Research Key statistical findings Hot Jupiters, P < 10 day, M > 0.1 Jupiter Planetary systems are common occurrence rate ~1% 23 systems with > 5 planets Most frequent around F, G stars (no analog in our solar system) credits: NASA/CXC/M. Weiss 7-planet Trappist-1 system, credit: NASA-JPL Earth-size rocky planets are ~10% of Sun-like stars and ~50% abundant of M-type stars have potentially habitable planets credits: NASA Ames/SETI Institute/JPL-Caltech Dressing & Charbonneau 2013 1. Current Status of Exoplanet Research Spectacular discoveries around M stars Trappist-1 system 7 planets ~3 in hab zone likely rocky 40 ly away Proxima Cen b planet Possibly habitable Closest star to our solar system Faint red M-type star 1. Current Status of Exoplanet Research Spectroscopic characterization limited to Giant young planets or close-in planets For most planets, only Mass, radius and orbit are constrained HR 8799 d planet (direct imaging) Currie, Burrows et al.
    [Show full text]
  • WTS-1 B: the first Extrasolar Planet Detected in the WFCAM Transit Survey
    WTS-1 b: the first extrasolar planet detected in the WFCAM Transit Survey Michele Cappetta M¨unchen2012 WTS-1 b: the first extrasolar planet detected in the WFCAM Transit Survey Michele Cappetta Dissertation an der Fakult¨atf¨urPhysik der Ludwig{Maximilians{Universit¨at M¨unchen vorgelegt von Michele Cappetta aus Bolzano, Italien M¨unchen, den 19. Dezember 2012 Erstgutachter: R. P. Saglia Zweitgutachter: B. Ercolano Tag der m¨undlichen Pr¨ufung:5. Februar 2013 Contents Zusammenfassung xix Summary xxi 1 Extrasolar planets 1 1.1 Introduction . .2 1.2 Detection methods . .4 1.3 Planet formation . .7 1.3.1 The Solar Nebular Model . .7 1.3.2 Rocky planets formation . .8 1.3.3 Gas-giant planets formation . 10 1.4 Planet evolution . 13 1.4.1 Gas disk migration . 13 1.4.2 Planetesimal-driven migration . 14 1.4.3 Planet-planet scattering . 16 1.5 Extrasolar planets properties . 17 1.5.1 Radius anomaly of the hot-Jupiters . 22 2 WFCAM Transit Survey 25 2.1 Observing strategy . 27 2.2 Reduction pipeline . 29 2.3 Transit detection algorithm . 32 2.4 Transit recovery ratios . 34 2.5 Results . 37 3 Instrumentation and spectroscopic observations 39 3.1 Hobby-Eberly Telescope . 40 3.2 The HRS Spectrograph . 42 3.3 Instrumental configurations . 46 3.4 Visit types . 49 4 Reduction and analysis pipeline 51 4.1 Introduction . 52 vi CONTENTS 4.2 Data reduction . 54 4.2.1 Cosmic-rays filtering . 54 4.2.2 Frames calibration . 54 4.2.3 Apertures definition . 55 4.2.4 Spectra extraction .
    [Show full text]
  • The Formation Mechanism of Gas Giants on Wide Orbits
    The Astrophysical Journal, 707:79–88, 2009 December 10 doi:10.1088/0004-637X/707/1/79 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE FORMATION MECHANISM OF GAS GIANTS ON WIDE ORBITS Sarah E. Dodson-Robinson1,4, Dimitri Veras2, Eric B. Ford2, and C. A. Beichman3 1 Astronomy Department, University of Texas, 1 University Station C1400, Austin, TX 78712, USA; [email protected] 2 Astronomy Department, University of Florida, 211 Bryant Space Sciences Center, Gainesville, FL 32111, USA 3 NASA Exoplanet Science Institute, California Institute of Technology, 770 S. Wilson Ave, Pasadena, CA 91125, USA Received 2009 July 29; accepted 2009 October 19; published 2009 November 18 ABSTRACT The recent discoveries of massive planets on ultra-wide orbits of HR 8799 and Fomalhaut present a new challenge for planet formation theorists. Our goal is to figure out which of three giant planet formation mechanisms— core accretion (with or without migration), scattering from the inner disk, or gravitational instability—could be responsible for Fomalhaut b, HR 8799 b, c and d, and similar planets discovered in the future. This paper presents the results of numerical experiments comparing the long-period planet formation efficiency of each possible mechanism in model A star, G star, and M star disks. First, a simple core accretion simulation shows that planet cores forming beyond 35 AU cannot reach critical mass, even under the most favorable conditions one can construct. Second, a set of N-body simulations demonstrates that planet–planet scattering does not create stable, wide-orbit systems such as HR 8799.
    [Show full text]
  • Download This Article in PDF Format
    A&A 637, A9 (2020) Astronomy https://doi.org/10.1051/0004-6361/201937239 & c O. Flasseur et al. 2020 Astrophysics PACO ASDI: an algorithm for exoplanet detection and characterization in direct imaging with integral field spectrographs Olivier Flasseur1, Loïc Denis1, Éric Thiébaut2, and Maud Langlois2 1 Université de Lyon, UJM-Saint-Etienne, CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, 42023 Saint-Etienne, France e-mail: [email protected] 2 Université de Lyon, Université Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon UMR 5574, 69230 Saint-Genis-Laval, France e-mail: [email protected] Received 3 December 2019 / Accepted 6 March 2020 ABSTRACT Context. Exoplanet detection and characterization by direct imaging both rely on sophisticated instruments (adaptive optics and coro- nagraph) and adequate data processing methods. Angular and spectral differential imaging (ASDI) combines observations at different times and a range of wavelengths in order to separate the residual signal from the host star and the signal of interest corresponding to off-axis sources. Aims. Very high contrast detection is only possible with an accurate modeling of those two components, in particular of the back- ground due to stellar leakages of the host star masked out by the coronagraph. Beyond the detection of point-like sources in the field of view, it is also essential to characterize the detection in terms of statistical significance and astrometry and to estimate the source spectrum. Methods. We extend our recent method PACO, based on local learning of patch covariances, in order to capture the spectral and tem- poral fluctuations of background structures.
    [Show full text]
  • Coronagraphic Imaging of Debris Disks from a High Altitude Balloon Platform
    Coronagraphic Imaging of Debris Disks From a High Altitude Balloon Platform Stephen Unwin >", Wesley 'Traub", Geoffrey Bryden", Paul Brugarolasa , Pin Chen", Olivier Guyonb, Lynne Hillenbrandc, John Krist", Bruce ~facintoshd , Dimitri 1Ifawete, Bertrand Mennesson", Dwight Moody", Lewis C. Roberts Jr.", Karl Stapelfeldt!, David Stuchlik9, John 'Traugera , and Gautam Vasisht" "Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 bNational Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720 cCalifornia Institute of Technology, Pasadena, CA 91125 dLawrence Livermore National Laboratory, Livermore, CA 94550 eEuropean Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago de Chile 19, Chile fNASA Goddard Space Flight Center, Greenbelt, MD 20771 9NASA Wallops Flight Facility, Wallops Island, VA 23337 ABSTRACT Debris disks around nearby stars are tracers of the planet formation process, and they are a key element of our understanding of the, formation and evolution of extrasolar planeta.ry systems. With multi-color images of a. significant number of disks, we can probe important questions: ca.'1. we learn about planetary system evolution; whflt materials are the disks made of; and can they reveal the presence of planets? :Most disks are known to exist only through their infrared flux excesses as measured by the Spitzer Space Telescope, and through images mesaured by Herschel. The brightest, most exte::tded disks have been imaged with HST, and a few, such as Fomalhaut, can be observed using ground-based telescopes. But the number of good images is still very small, and there are none of disks with densitips as low as the disk associated with the asteroid belt and Edgeworth­ Kuiper belt in our own Solar System.
    [Show full text]