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White dwarfs in wide binaries: the strong effects of stellar evolution and mass loss
Hsiang-Chih Hwang, Nadia Zakamska
We examine the statistics of main-sequence / main-sequence, main-sequence / white-dwarf and white-dwarf / white-dwarf wide binaries at 10^2.5-10^4 AU separations in Gaia data. For…
Measuring The Mass-Radius Relation of White Dwarfs Using Wide Binaries
Stefan Arseneau, Vedant Chandra, Hsiang-Chih Hwang +10
Measuring the mass-radius relation of individual white dwarfs is an empirically challenging task that has been performed for only a few dozen stars. We measure the white dwarf mass…
Discovery of a Proto-White Dwarf with a Massive Unseen Companion
Gautham Adamane Pallathadka, Vedant Chandra, Nadia L. Zakamska +8
We report the discovery of SDSS~J022932.28+713002.7, a nascent extremely low-mass (ELM) white dwarf (WD) orbiting a massive ( at 2 confidence) companion with a per…
Dynamical masses across the Hertzsprung-Russell diagram
Hsiang-Chih Hwang, Yuan-Sen Ting, Sihao Cheng +1
We infer the dynamical masses of stars across the Hertzsprung-Russell (H-R) diagram using wide binaries from the Gaia survey. Gaia's high-precision astrometry measures the wide bin…
Cataclysmic Variables from Sloan Digital Sky Survey V -- the search for period bouncers continues
K. Inight, Boris T. Gänsicke, A. Schwope +25
SDSS-V is carrying out a dedicated survey for white dwarfs, single and in binaries, and we report the analysis of the spectroscopy of cataclysmic variables (CVs) and CV candidates…
CSS1603+19: a low-mass polar near the cataclysmic variable period minimum
Yiqi Liu, Hsiang-Chih Hwang, Nadia L. Zakamska +1
CSS1603+19 is a cataclysmic variable (CV) with an orbital period of 81.96 min, near the minimal period of cataclysmic variables. It is unusual in having a strong mid-infrared exces…
The mystery in Gaia DR3 triples: occurrence rates, orientations, and eccentricities of wide tertiaries around close binaries
Hsiang-Chih Hwang
The formation of close binaries has been an open question for decades. A large fraction of close binaries are in triple systems, suggesting that their formation may be associated w…
Wide twin binaries are extremely eccentric: evidence of twin binary formation in circumbinary disks
Hsiang-Chih Hwang, Kareem El-Badry, Hans-Walter Rix +3
The Gaia mission recently revealed an excess population of equal-mass "twin" wide binaries, with mass ratio , extending to separations of at least 1000 AU. The origi…
Enhancement of Double-Close-Binary Quadruples
Gavin B. Fezenko, Hsiang-Chih Hwang, Nadia L. Zakamska
Double-close-binary quadruples (2+2 systems) are hierarchical systems of four stars where two short-period binary systems move around their common center of mass on a wider orbit.…
The eccentricity distribution of wide binaries and their individual measurements
Hsiang-Chih Hwang, Yuan-Sen Ting, Nadia L. Zakamska
Eccentricity of wide binaries is difficult to measure due to their long orbital periods. With Gaia's high-precision astrometric measurements, eccentricity of a wide binary can be c…
The SNIa Runaway LP 398-9: Detection of Circumstellar Material and Surface Rotation
Vedant Chandra, Hsiang-Chih Hwang, Nadia L. Zakamska +12
A promising progenitor scenario for Type Ia supernovae (SNeIa) is the thermonuclear detonation of a white dwarf in a close binary system with another white dwarf. After the primary…
A 99-minute Double-lined White Dwarf Binary from SDSS-V
Vedant Chandra, Hsiang-Chih Hwang, Nadia L. Zakamska +12
We report the discovery of SDSS J133725.26+395237.7 (hereafter SDSS J1337+3952), a double-lined white dwarf (WD+WD) binary identified in early data from the fifth generation Sloan…
Variability, periodicity and contact binaries in WISE
Evan Petrosky, Hsiang-Chih Hwang, Nadia L. Zakamska +2
The time-series component of WISE is a valuable resource for the study of variable objects. We present an analysis of an all-sky sample of ~450,000 AllWISE+NEOWISE infrared light c…
The non-monotonic, strong metallicity dependence of the wide-binary fraction
Hsiang-Chih Hwang, Yuan-Sen Ting, Kevin C. Schlaufman +2
The metallicity dependence of the wide-binary fraction in stellar populations plays a critical role in resolving the open question of wide binary formation. In this paper, we inves…
A Gravitational Redshift Measurement of the White Dwarf Mass-Radius Relation
Vedant Chandra, Hsiang-Chih Hwang, Nadia L. Zakamska +1
The mass-radius relation of white dwarfs is largely determined by the equation of state of degenerate electrons, which causes the stellar radius to decrease as mass increases. Here…
Computational Tools for the Spectroscopic Analysis of White Dwarfs
Vedant Chandra, Hsiang-Chih Hwang, Nadia L. Zakamska +1
The spectroscopic features of white dwarfs are formed in the thin upper layer of their stellar photosphere. These features carry information about the white dwarf's surface tempera…
Lifetime of short-period binaries measured from their Galactic kinematics
Hsiang-Chih Hwang, Nadia Zakamska
As a significant fraction of stars are in multiple systems, binaries play a crucial role in stellar evolution. Among short-period (<1 day) binary characteristics, age remains one o…