Gemini Planet Imager Observations of a Resolved Low-inclination Debris Disk around HD 156623

Briley Lewis (1) , Michael Fitzgerald (1) , Thomas Esposito (2) , Pauline Arriaga (1) , Ronald López (1) , Katie Crotts (3) , Gaspard Duchêne (4) , Katherine Follette (5) , Justin Hom (6) , Paul Kalas (2) , Brenda Matthews (3) , Maxwell Millar-Blanchaer (7) , David Wilner (8) , Johan Mazoyer (9, 10) , Bruce Macintosh (11)

1 Department of Physics and Astronomy [UCLA, Los Angeles]
2 Department of Astronomy [Berkeley]
3 UVIC - University of Victoria [Canada]
4 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
5 Amherst College
6 Steward Observatory
7 UC Santa Barbara - University of California [Santa Barbara]
8 CfA - Harvard-Smithsonian Center for Astrophysics
9 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics
10 Observatoire de Paris
11 UC Santa Cruz - University of California [Santa Cruz]

Abstract The 16 Myr old A0V star HD 156623 in the Scorpius–Centaurus association hosts a high-fractional-luminosity debris disk, recently resolved in scattered light for the first time by the Gemini Planet Imager (GPI) in polarized intensity only. We present a new analysis of the GPI H -band polarimetric detection of the HD 156623 debris disk, with particular interest in its unique morphology. This debris disk lacks a visible inner clearing, unlike the majority of low-inclination disks in the GPI sample and in Sco-Cen, and it is known to contain CO gas, positioning it as a candidate “hybrid” or “shielded” disk. We use radiative transfer models to constrain the geometric parameters of the disk based on scattered light data and thermal models to constrain the unresolved inner radius based on the system’s spectral energy distribution (SED). We also compute a measurement of the polarized scattering phase function, adding to the existing sample of empirical phase function measurements. We find that HD 156623's debris disk inner radius is constrained to less than 26.6 au from scattered light imagery and less than 13.4 au from SED modeling at a 99.7% confidence interval and suggest that gas drag may play a role in retaining sub-blowout-size dust grains so close to the star.

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]

Briley Lewis, Michael Fitzgerald, Thomas Esposito, Pauline Arriaga, Ronald López, et al.. Gemini Planet Imager Observations of a Resolved Low-inclination Debris Disk around HD 156623. The Astronomical Journal, 2024, 168 (4), pp.142. ⟨10.3847/1538-3881/ad67e1⟩. ⟨hal-04749968⟩