Preprint
A New Sirius-like System at Only 21 Parsecs: An Elusive White Dwarf Companion to the Nearby K-dwarf HD 38230
arXiv
ArXiv
07/30/2026
DOI: 10.48550/arxiv.2607.28720
Abstract
White dwarfs are among the rarest and faintest stars found in the solar neighbourhood and are therefore persistently challenging to detect. Whereas the Gaia mission has vastly expanded our knowledge of isolated white dwarfs, limited contrast sensitivity means that white dwarfs companions to much brighter solar-type stars are easily missed, leaving a subset of white dwarfs in "Sirius-like systems" that can only be discovered via high-contrast imaging. Here we report the discovery of a white dwarf companion to the nearby K0V star HD 38230 (HIP 27207). The companion, HD 38230 B, was originally detected with Keck/NIRC2 observations taken as part of the TRENDS high-contrast imaging survey, was detected by Gaia without an astrometric solution, and was independently observed using Lick/ShaneAO and Palomar/PHARO in the literature. Combining these multiple imaging detections spanning 6 years, we demonstrate that HD 38230 B is a gravitationally bound companion and has photometry consistent only with a white dwarf. Our analysis of the binary orbit, combining relative astrometry with over 25 years of precise radial velocity observations and Hipparcos-Gaia astrometry, results in strong constraints on theP=1390⁺³¹⁰₋₂₀₀year orbit despite the short observational span, and provides a precise dynamical mass ofM_(B)=0.71^(+0.06)_(-0.05)M_(⊙)for the white dwarf. At 21 pc, this is the 11th-nearest Sirius-like system known to date, highlighting residual incompleteness in the local white dwarf census.
Details
- Title: Subtitle
- A New Sirius-like System at Only 21 Parsecs: An Elusive White Dwarf Companion to the Nearby K-dwarf HD 38230
- Creators
- Alexander VennerLogan A PearceQier AnClémence FontaniveElisabeth C MatthewsKyle FransonJustin R CreppHai FuTimothy D Brandt
- Resource Type
- Preprint
- Publication Details
- arXiv
- DOI
- 10.48550/arxiv.2607.28720
- ISSN
- 2331-8422
- Publisher
- ArXiv
- Language
- English
- Date posted
- 07/30/2026
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9985217832102771
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