Collisions in a gas-rich white dwarf planetary debris disc. (arXiv:2106.09025v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Swan_A/0/1/0/all/0/1">Andrew Swan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kenyon_S/0/1/0/all/0/1">Scott J. Kenyon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Farihi_J/0/1/0/all/0/1">Jay Farihi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dennihy_E/0/1/0/all/0/1">Erik Dennihy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gansicke_B/0/1/0/all/0/1">Boris T. G&#xe4;nsicke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hermes_J/0/1/0/all/0/1">J. J. Hermes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Melis_C/0/1/0/all/0/1">Carl Melis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hippel_T/0/1/0/all/0/1">Ted von Hippel</a>

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 micron 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.

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 micron 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.

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