VLT/SPHERE exploration of the young multiplanetary system PDS70

Context. PDS 70 is a young (5.4 Myr), nearby (~113 pc) star hosting a known transition disk with a large gap. Recent observations with SPHERE and NACO in the near-infrared (NIR) allowed us to detect a planetary mass companion, PDS 70 b, within the disk cavity. Moreover, observations in Hα with MagAO and MUSE revealed emission associated to PDS 70 b and to another new companion candidate, PDS 70 c, at a larger separation from the star. PDS 70 is the only multiple planetary system at its formation stage detected so far through direct imaging. Aims. Our aim is to confirm the discovery of the second planet PDS 70 c using SPHERE at VLT, to further characterize its physical properties, and search for additional point sources in this young planetary system. Methods. We re-analyzed archival SPHERE NIR observations and obtained new data in Y, J, H and K spectral bands for a total of four different epochs. The data were reduced using the data reduction and handling pipeline and the SPHERE data center. We then applied custom routines (e.g., ANDROMEDA and PACO) to subtract the starlight. Results. We re-detect both PDS 70 b and c and confirm that PDS 70 c is gravitationally bound to the star. We estimate this second planet to be less massive than 5 MJup and with a Teff around 900 K. Also, it has a low gravity with logg between 3.0 and 3.5 dex. In addition, a third object has been identified at short separation (~0.12′′) from the star and gravitationally bound to the star. Its spectrum is however very blue, meaning that we are probably seeing stellar light reflected by dust and our analysis seems to demonstrate that it is a feature of the inner disk. We cannot however completely exclude the possibility that it is a planetary mass object enshrouded by a dust envelope. In this latter case, its mass should be of the order of a few tens of M⊕. Moreover, we propose a possible structure for the planetary system based on our data, and find that this structure cannot be stable on a long timescale.

[1]  Zhaohuan Zhu,et al.  An Ideal Testbed for Planet–Disk Interaction: Two Giant Protoplanets in Resonance Shaping the PDS 70 Protoplanetary Disk , 2019, The Astrophysical Journal.

[2]  Stefano Facchini,et al.  Detection of Continuum Submillimeter Emission Associated with Candidate Protoplanets , 2019, The Astrophysical Journal.

[3]  Julien H. Girard,et al.  Evidence for a Circumplanetary Disk around Protoplanet PDS 70 b , 2019, The Astrophysical Journal.

[4]  J. Szulágyi,et al.  Observability of forming planets and their circumplanetary discs II. – SEDs and near-infrared fluxes , 2019, Monthly Notices of the Royal Astronomical Society.

[5]  Julien H. Girard,et al.  Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI , 2019, Monthly Notices of the Royal Astronomical Society.

[6]  T. Henning,et al.  Highly structured disk around the planet host PDS 70 revealed by high-angular resolution observations with ALMA , 2019, Astronomy & Astrophysics.

[7]  Julien H. Girard,et al.  SPHERE: the exoplanet imager for the Very Large Telescope , 2019, Astronomy & Astrophysics.

[8]  D. Fantinel,et al.  Blobs, spiral arms, and a possible planet around HD 169142 , 2019, Astronomy & Astrophysics.

[9]  Frantz Martinache,et al.  Isochronal age-mass discrepancy of young stars: SCExAO/CHARIS integral field spectroscopy of the HIP 79124 triple system , 2018, Astronomy & Astrophysics.

[10]  Dmitry Savransky,et al.  Dynamical Constraints on the HR 8799 Planets with GPI , 2018, The Astronomical Journal.

[11]  A. Boccaletti,et al.  High-contrast study of the candidate planets and protoplanetary disk around HD 100546 , 2018, Astronomy & Astrophysics.

[12]  Laird M. Close,et al.  Magellan Adaptive Optics Imaging of PDS 70: Measuring the Mass Accretion Rate of a Young Giant Planet within a Gapped Disk , 2018, The Astrophysical Journal Letters.

[13]  C. Moutou,et al.  Imaging radial velocity planets with SPHERE , 2018, Monthly Notices of the Royal Astronomical Society.

[14]  L. Mugnier,et al.  The GJ 504 system revisited , 2018, Astronomy & Astrophysics.

[15]  T. Fusco,et al.  Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk , 2018, Astronomy & Astrophysics.

[16]  D. Fantinel,et al.  Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70 , 2018, Astronomy & Astrophysics.

[17]  A. Vigan,et al.  Astrometric and photometric accuracies in high contrast imaging: The SPHERE speckle calibration tool (SpeCal) , 2018, Astronomy & Astrophysics.

[18]  T. A. Lister,et al.  Gaia Data Release 2. Summary of the contents and survey properties , 2018, 1804.09365.

[19]  Olivier Flasseur,et al.  Exoplanet detection in angular differential imaging by statistical learning of the nonstationary patch covariances , 2018, Astronomy & Astrophysics.

[20]  J. Wisniewski,et al.  Differences in the Gas and Dust Distribution in the Transitional Disk of a Sun-like Young Star, PDS 70 , 2018, 1804.00529.

[21]  Anthony Boccaletti,et al.  A Self-consistent Cloud Model for Brown Dwarfs and Young Giant Exoplanets: Comparison with Photometric and Spectroscopic Observations , 2017, 1711.11483.

[22]  Julien H. Girard,et al.  Investigation of the inner structures around HD 169142 with VLT/SPHERE , 2017, 1709.01734.

[23]  S. Rabien,et al.  First light for GRAVITY: Phase referencing optical interferometry for the Very Large Telescope Interferometer , 2017, 1705.02345.

[24]  Julien H. Girard,et al.  Multiple rings in the transition disk and companion candidates around RX J1615.3-3255. High contrast imaging with VLT/SPHERE , 2016, 1610.04038.

[25]  Observatoire de la Côte d'Azur,et al.  Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties , 2016, 1609.04172.

[26]  E. Mamajek,et al.  The star formation history and accretion-disc fraction among the K-type members of the Scorpius–Centaurus OB association , 2016, 1605.08789.

[27]  R. Galicher,et al.  ASTROMETRIC MONITORING OF THE HR 8799 PLANETS: ORBIT CONSTRAINTS FROM SELF-CONSISTENT MEASUREMENTS , 2016, 1604.08157.

[28]  D. Fantinel,et al.  First light of the VLT planet finder SPHERE IV : Physical and chemical properties of the planets around HR8799 , 2015, 1511.04082.

[29]  D. Mouillet,et al.  Direct exoplanet detection and characterization using the ANDROMEDA method: Performance on VLT/NaCo data , 2015, 1508.06406.

[30]  A. Boccaletti,et al.  Interpreting the photometry and spectroscopy of directly imaged planets: a new atmospheric model applied to β Pictoris b and SPHERE observations , 2015, 1504.04876.

[31]  D. Fantinel,et al.  Performance of the VLT Planet Finder SPHERE - II. Data analysis and results for IFS in laboratory , 2015, 1503.02486.

[32]  J. Wisniewski,et al.  THE STRUCTURE OF PRE-TRANSITIONAL PROTOPLANETARY DISKS. II. AZIMUTHAL ASYMMETRIES, DIFFERENT RADIAL DISTRIBUTIONS OF LARGE AND SMALL DUST GRAINS IN PDS 70, , 2014, 1411.2587.

[33]  T. Fusco,et al.  Performance of the VLT Planet Finder SPHERE I. Photometry and astrometry precision with IRDIS and IFS in laboratory , 2014, 1410.1754.

[34]  Bruce Macintosh,et al.  GPI PSF subtraction with TLOCI: the next evolution in exoplanet/disk high-contrast imaging , 2014, Astronomical Telescopes and Instrumentation.

[35]  S. Morrison,et al.  PLANETARY CHAOTIC ZONE CLEARING: DESTINATIONS AND TIMESCALES , 2014, 1411.1378.

[36]  R. Smart,et al.  The extremely red L dwarf ULAS J222711 004547 - dominated by dust. , 2014, 1401.0420.

[37]  A. Lançon,et al.  SF2A-2013: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics , 2013 .

[38]  C. Moutou,et al.  Astrophysical false positives in direct imaging for exoplanets: a white dwarf close to a rejuvenated star , 2013, 1304.4130.

[39]  Timothy D. Brandt,et al.  THE STRUCTURE OF PRE-TRANSITIONAL PROTOPLANETARY DISKS. I. RADIATIVE TRANSFER MODELING OF THE DISK+CAVITY IN THE PDS 70 SYSTEM , 2012, 1209.3772.

[40]  Olivier Guyon,et al.  POLARIMETRIC IMAGING OF LARGE CAVITY STRUCTURES IN THE PRE-TRANSITIONAL PROTOPLANETARY DISK AROUND PDS 70: OBSERVATIONS OF THE DISK , 2012, 1208.2075.

[41]  R. Soummer,et al.  DETECTION AND CHARACTERIZATION OF EXOPLANETS AND DISKS USING PROJECTIONS ON KARHUNEN–LOÈVE EIGENIMAGES , 2012, 1207.4197.

[42]  M. Barbieri,et al.  A giant planet in the triple system HD 132563 , 2011, 1107.0918.

[43]  Julien H. Girard,et al.  High angular resolution detection of β Pictoris b at 2.18 μm , 2011 .

[44]  David Mouillet,et al.  Photometric characterization of exoplanets using angular and spectral differential imaging , 2010, 1004.4825.

[45]  M. Bate,et al.  Circumplanetary disc properties obtained from radiation hydrodynamical simulations of gas accretion by protoplanets , 2009, 0904.4884.

[46]  C. Migaszewski,et al.  Is the HR 8799 extrasolar system destined for planetary scattering , 2009, 0904.4106.

[47]  B. Macintosh,et al.  Direct Imaging of Multiple Planets Orbiting the Star HR 8799 , 2008, Science.

[48]  D. Mawet,et al.  Coronagraphic imaging of three weak-line T Tauri stars: evidence of planetary formation around PDS 70 , 2006 .

[49]  M. Meyer,et al.  Ten Micron Observations of Nearby Young Stars , 2003, astro-ph/0309453.

[50]  B. Draine.  INTERSTELLAR DUST GRAINS , 2003, astro-ph/0304489.

[51]  H. Beust.  Symplectic integration of hierarchical stellar systems , 2003 .

[52]  F. Allard,et al.  The Limiting Effects of Dust in Brown Dwarf Model Atmospheres , 2001, astro-ph/0104256.

[53]  W. W. Duley,et al.  Ultraviolet and Infrared Refractive Indices of Amorphous Silicates , 1996 .

[54]  James R. Graham,et al.  Exploring the formation and evolution of planetary systems : proceedings of the 299th symposium of the International Astronomical Union, held in Victoria, Canada, June 2-7, 2013 , 2013 .

[55]  Gilbert E. Satterthwaite,et al.  Encyclopedia of astronomy , 1970 .

[56]  Leendert Binnendijk,et al.  Properties of Double Stars: A Survey of Parallaxes and Orbits , 1960 .