oai:arXiv.org:2406.18646
sciences: astrophysics
2024
7/3/2024
Roughly 2% of white dwarfs harbor planetary debris disks detectable via infrared excesses, but only a few percent of these disks show a gaseous component, distinguished by their double-peaked emission at the near-infrared calcium triplet.
Previous studies found most debris disks around white dwarfs are variable at 3.4 and 4.5 $\mu$m, but they analyzed only a few of the now 21 published disks showing calcium emission.
To test if most published calcium emission disks exhibit large-amplitude stochastic variability in the near-infrared, we use light curves generated from the unWISE images at 3.4 $\mu$m that are corrected for proper motion to characterize the near-infrared variability of these disks against samples of disks without calcium emission, highly variable cataclysmic variables, and 3215 isolated white dwarfs.
We find most calcium emission disks are extremely variable: 6/11 with sufficient signal-to-noise show high-amplitude variability in their 3.4-$\mu$m light curves.
These results lend further credence to the notion that disks showing gaseous debris in emission are the most collisionally active.
Under the assumption that 3.4-$\mu$m variability is characteristic of white dwarfs with dusty debris disks, we generate a catalog of 104 high-confidence near-infrared variable white dwarfs, 84 of which are published as variable for the first time.
We do near-infrared spectroscopic follow-up of seven new candidate 3.4-$\mu$m variables, confirming at least one new remnant planetary system, and posit that empirical near-infrared variability can be a discovery engine for debris disks showing gaseous emission.
;Comment: 27 pages, 8 figures, accepted to The Astrophysical Journal.
Supplemental catalogs and light curves available at https://zenodo.org/doi/10.5281/zenodo.12538705
Guidry, Joseph A.,Hermes, J. J.,De, Kishalay,Rouis, Lou Baya Ould,Ewing, Brison B.,Kaiser, B. C., 2024, Using 3.4-$\mu$m Variability towards White Dwarfs as a Signpost of Remnant Planetary Systems