Direct Distance Measurement to the Dusty White Dwarf GD 362

TL;DR

This study accurately measures the distance to the white dwarf GD 362 using parallax, refining its mass and radius estimates, and clarifies its classification, impacting understanding of dust disks around white dwarfs.

Contribution

First direct distance measurement to GD 362, leading to revised mass and radius estimates, and clarification of its properties compared to prior assumptions.

Findings

GD 362 is at 50.6 parsecs distance

Its mass is approximately 0.71 solar masses

It is not as massive as previously thought

Abstract

We present trigonometric parallax observations of GD 362 obtained over seven epochs using the MDM 2.4m Hiltner Telescope. The existence of a dust disk around this possibly massive white dwarf makes it an interesting target for parallax observations. The measured parallax for GD 362 places it at a distance of 50.6 pc, which implies that its radius and mass are ~ 0.0106 Rsun and 0.71 Msun, respectively. GD 362 is not as massive as initially thought (1.2Msun). Our results are entirely consistent with the distance and mass estimates (52.2 pc and 0.73 Msun) by Zuckerman et al., who demonstrated that GD 362 has a helium dominated atmosphere. Dropping GD 362 from the list of massive white dwarfs, there are no white dwarfs with M > 0.9 Msun that are known to host circumstellar dust disks.