Dust Recycling over the 2 hour Period of a White Dwarf Planetesimal
Abstract
It is now known that 30-50% of white dwarfs are accreting planetary material from circumstellar debris disks. Spitzer has played a key role in the discovery of circumstellar dust at 40 of these systems via detection of infrared excess emission. Circumstellar gas that is co-spatial with the dust has also been detected around eight white dwarfs, however the origin of such gas is still unknown. WD 1226+110 is the prototype disk with gaseous emission and has recently been observed to have gas velocity variation with a period of 123.4 min. We propose this is due to gas production via collisions between a co-orbiting planetesimal and dust disk. Gas should rapidly re-condense into dust, providing a recycling channel for further collisions. We expect that this scenario of dust production and destruction results in stochastic infrared flux variations on orbital timescales. We propose a 4.9 h, high-cadence staring mode observation of WD 1226+110 that covers two orbital periods of the planetesimal to discover and characterize flux variations indicative of dust recycling. Currently, Spitzer is the only facility that can probe the dust in this compelling system, and the proposed observations will pave the way for studies with future facilities.
- Publication:
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Spitzer Proposal
- Pub Date:
- May 2019
- Bibcode:
- 2019sptz.prop14274W