Collisions in a gas-rich white dwarf planetary debris disc

Andrew Swan; Scott J Kenyon; Jay Farihi; Erik Dennihy; Boris T Gänsicke; J J Hermes; Carl Melis; Ted von Hippel

doi:10.1093/mnras/stab1738

Collisions in a gas-rich white dwarf planetary debris disc

Mon Not R Astron Soc. 2021 Jun 21;506(1):432-440. doi: 10.1093/mnras/stab1738. eCollection 2021 Sep.

Authors

Andrew Swan¹, Scott J Kenyon², Jay Farihi¹, Erik Dennihy³, Boris T Gänsicke⁴, J J Hermes⁵, Carl Melis⁶, Ted von Hippel⁷

Affiliations

¹ Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
² Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138, USA.
³ Gemini Observatory/NSF's NOIRLab, Casilla 603, La Serena, Chile.
⁴ Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
⁵ Department of Astronomy & Institute for Astrophysical Research, Boston University, 725 Commonwealth Ave., Boston, MA 02215, USA.
⁶ Center for Astrophysics and Space Sciences, University of California, San Diego, CA 92093-0424, USA.
⁷ Department of Physical Sciences, Embry-Riddle Aeronautical University, Daytona Beach, FL 32114, USA.

Abstract

WD 0145+234 is a white dwarf that is accreting metals from a circumstellar disc of planetary material. It has exhibited a substantial and sustained increase in 3-5 [Formula: see text]m flux since 2018. Follow-up Spitzer photometry reveals that emission from the disc had begun to decrease by late 2019. Stochastic brightening events superimposed on the decline in brightness suggest the liberation of dust during collisional evolution of the circumstellar solids. A simple model is used to show that the observations are indeed consistent with ongoing collisions. Rare emission lines from circumstellar gas have been detected at this system, supporting the emerging picture of white dwarf debris discs as sites of collisional gas and dust production.

Keywords: circumstellar matter; planetary systems; stars: individual: WD 0145+234; white dwarfs.