Discovery of a warm, dusty giant planet around HIP 65426

By G. Chauvin, S. Desidera, Anne-Marie Lagrange, A. Vigan, R. Gratton, Maud Langlois, M. Bonnefoy, J. Beuzit, M. Feldt, David Mouillet and 113 more. 2017

170 citations recorded by the source corpus.

Aims. The SHINE program is a high-contrast near-infrared survey of 600 young, nearby stars aimed at searching for and characterizing new planetary systems using VLT/SPHERE’s unprecedented high-contrast and high-angular-resolution imaging capabilities. It is also intended to place statistical constraints on the rate, mass and orbital distributions of the giant planet population at large orbits as a function of the stellar host mass and age to test planet-formation theories. Methods. We used the IRDIS dual-band imager and the IFS integral field spectrograph of SPHERE to acquire high-contrast coronagraphic differential near-infrared images and spectra of the young A2 star HIP 65426. It is a member of the ~17 Myr old Lower Centaurus-Crux association. Results. At a separation of 830 mas (92 au projected) from the star, we detect a faint red companion. Multi-epoch observations confirm that it shares common proper motion with HIP 65426. Spectro-photometric measurements extracted with IFS and IRDIS between 0.95 and 2.2 μm indicate a warm, dusty atmosphere characteristic of young low-surface-gravity L5-L7 dwarfs. Hot-start evolutionary models predict a luminosity consistent with a 6–12 MJup, Teff = 1300–1600 K and R = 1.5 ± 0.1 RJup giant planet. Finally, the comparison with Exo-REM and PHOENIX BT-Settl synthetic atmosphere models gives consistent effective temperatures but with slightly higher surface gravity solutions of log (g) = 4.0–5.0 with smaller radii (1.0–1.3 RJup). Conclusions. Given its physical and spectral properties, HIP 65426 b occupies a rather unique placement in terms of age, mass, and spectral-type among the currently known imaged planets. It represents a particularly interesting case to study the presence of clouds as a function of particle size, composition, and location in the atmosphere, to search for signatures of non-equilibrium chemistry, and finally to test the theory of planet formation and evolution.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/daecf4762826bc61febafbb7f003dd5c84e9a196

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Citations in the corpus

• SPHERE: the exoplanet imager for the Very Large Telescope (2019, methodology): “…with the preparation of the observations in Phase 2, and ending with the analysis of large quantities of data in the context of the SHINE survey (Chauvin et al. 2017), a number of tools have been developed and deployed within the SPHERE consortium which are partially available to the general…”
• Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70 (2018, methodology): “During the guaranteed time observations (GTO) of the SPHERE consortium, PDS 70 was observed twice within the SHINE (SpHere INfrared survey for Exoplanets; Chauvin et al. 2017a) program on the nights of May 3, 2015, and May 31, 2015.”
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics from 10 to 100 au (2019, methodology): “…(Pecaut & Mamajek 2016a) Lower Centaurus Crux subgroup of the Scorpius-Centaurus OB2 association (Rizzuto et al. 2011) using VLT/NaCo in 2011 (Rameau et al. 2013a, 2013b), one of a growing number of exoplanets that have been resolved around Sco-Cen members (Bailey et al. 2014; Chauvin et al. 2017).”