TY - JOUR
T1 - The Geometry of the G29-38 White Dwarf Dust Disk from Radiative Transfer Modeling
AU - Ballering, Nicholas P.
AU - Levens, Colette I.
AU - Su, Kate Y.L.
AU - Cleeves, L. Ilsedore
N1 - Funding Information:
We thank the referee for providing helpful feedback on this paper. We thank Dr. Mukremin Kilic for sharing with us the SpeX data. We thank Siyi Xu, Amy Bonsor, Erik Dennihy, and Johan Olofsson for useful feedback on this project. We also gratefully acknowledge the use of the University of Virginia Rivanna High-Performance Computing system, which was utilized to run the radiative transfer models presented in this work. N.P.B and K.Y.L.S acknowledge support from NASA XRP grant 80NSSC22K0234. N.P.B. and C.I.L. acknowledge support from the Virginia Initiative on Cosmic Origins (VICO).
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/11/1
Y1 - 2022/11/1
N2 - Many white dwarfs host disks of dust produced by disintegrating planetesimals and revealed by infrared excesses. The disk around G29-38 was the first to be discovered and is now well-observed, yet we lack a cohesive picture of its geometry and dust properties. Here we model the G29-38 disk for the first time using radiative transfer calculations that account for radial and vertical temperature and optical depth gradients. We arrive at a set of models that can match the available infrared measurements well, although they overpredict the width of the 10 μm silicate feature. The resulting set of models has a disk inner edge located at 92-100 R WD (where R WD is the white dwarf radius). This is farther from the star than inferred by previous modeling efforts due to the presence of a directly illuminated front edge to the disk. The radial width of the disk is narrow (≤10 R WD); such a feature could be explained by inefficient spreading or the proximity of the tidal disruption radius to the sublimation radius. The models have a half-opening angle of ≥1.°4. Such structure would be in strong contradiction with the commonly employed flat-disk model analogous to the rings of Saturn, and in line with the vertical structure of main-sequence debris disks. Our results are consistent with the idea that disks are collisionally active and continuously fed with new material, rather than evolving passively after the disintegration of a single planetesimal.
AB - Many white dwarfs host disks of dust produced by disintegrating planetesimals and revealed by infrared excesses. The disk around G29-38 was the first to be discovered and is now well-observed, yet we lack a cohesive picture of its geometry and dust properties. Here we model the G29-38 disk for the first time using radiative transfer calculations that account for radial and vertical temperature and optical depth gradients. We arrive at a set of models that can match the available infrared measurements well, although they overpredict the width of the 10 μm silicate feature. The resulting set of models has a disk inner edge located at 92-100 R WD (where R WD is the white dwarf radius). This is farther from the star than inferred by previous modeling efforts due to the presence of a directly illuminated front edge to the disk. The radial width of the disk is narrow (≤10 R WD); such a feature could be explained by inefficient spreading or the proximity of the tidal disruption radius to the sublimation radius. The models have a half-opening angle of ≥1.°4. Such structure would be in strong contradiction with the commonly employed flat-disk model analogous to the rings of Saturn, and in line with the vertical structure of main-sequence debris disks. Our results are consistent with the idea that disks are collisionally active and continuously fed with new material, rather than evolving passively after the disintegration of a single planetesimal.
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U2 - 10.3847/1538-4357/ac9a4a
DO - 10.3847/1538-4357/ac9a4a
M3 - Article
AN - SCOPUS:85142064790
SN - 0004-637X
VL - 939
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 108
ER -