A Helium White Dwarf of Extremely Low Mass

Abstract

We analyze the spectrum of an unusually-low mass white dwarf, SDSSJ123410.37-022802.9 (0335-264-52000), found in our recent, white dwarf catalog from the SDSS DR1 data release. Two independent, model atmosphere fits result in an accurate determination of atmospheric and stellar parameters. The more hands-on analysis yields $T_{\mathrm{eff}}$ =17,470$\pm$750 K and $\log g$ = 6.38$\pm$0.05. We argue that the object cannot be a main sequence A star, a horizontal branch or subdwarf B star. Instead, it is interpreted as a very low mass white dwarf with a core composed of helium, with mass ($\sim$0.18-0.19$M_{\odot }$), similar to that published previously for the unusual companion to the millisecond pulsar J1012+5307. The star probably remains in a binary, perhaps even with an undiscovered or dead pulsar companion. However, the companion might be a more-ordinary star, provided Roche lobe mass transfer began shortly after the now-visible component left the main sequence. A second SDSS low mass white dwarf candidate is also analyzed, but the spectrum for this fainter object is of poorer quality. The sample appears to include additional, similar candidates, worthy of more accurate observation. Correct identification of any additional white dwarfs of extremely low mass requires careful observation and interpretation.

ApJ Letters, v.606, 2004 May 10

References in corpus (7)

• The First Data Release of the Sloan Digital Sky Survey
• A Catalog of Spectroscopically Identified White Dwarf Stars in the First Data Release of the Sloan Digital Sky Survey
• The masses of the millisecond pulsar J1012+5307 and its white-dwarf companion
• Diffusion and the occurrence of hydrogen shell flashes in helium white dwarf stars
• An Initial Survey of White Dwarfs in the Sloan Digital Sky Survey
• The ages and colours of cool helium-core white dwarf stars
• Projected rotational velocities of WD1614+136 and WD1353+409 - implications for the rate of galactic Type Ia supernovae

Cited by in corpus (50)

• The Formation Rate, Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey
• An Improved Spectroscopic Analysis of DA White Dwarfs from the Sloan Digital Sky Survey Data Release 4
• A Catalog of Spectroscopically Confirmed White Dwarfs from the Sloan Digital Sky Survey Data Release 4
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• Hot subluminous stars
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• DA white dwarfs in SDSS DR7 and a search for infrared excess emission
• The ELM Survey. II. Twelve Binary White Dwarf Merger Systems
• The chemical diversity of exo-terrestrial planetary debris around white dwarfs
• Hypervelocity Stars. I. The Spectroscopic Survey
• On type Ia supernovae and the formation of single low-mass white dwarfs
• The ELM Survey. IV. 24 White Dwarf Merger Systems
• The Future is Now: the Formation of Single Low Mass White Dwarfs in the Solar Neighborhood
• Post-common envelope binaries from SDSS-X: The origin of low-mass white dwarfs
• The Lowest Mass White Dwarf
• Initial-Final Mass Relationship for Stars of Different Metallicities
• Magnetic White Dwarfs from the SDSS II. The Second and Third Data Releases
• Precise Atmospheric Parameters for the Shortest Period Binary White Dwarfs: Gravitational Waves, Metals, and Pulsations
• Hot subdwarf stars in close-up view I. Rotational properties of subdwarf B stars in close binary systems and nature of their unseen companions
• Kepler Observations of Transiting Hot Compact Objects
• Self-lensing Discovery of a $0.2M_{\odot }$ White Dwarf in an Unusually Wide Orbit Around a Sun-like Star
• Discovery of a Bright, Extremely Low-Mass White Dwarf in a Close Double Degenerate System
• High resolution spectroscopy of bright subdwarf B stars - I. Radial velocity variables
• Stability of super-Chandrasekhar magnetic white dwarfs
• Calcium-Rich Gap Transients: Tidal Detonations of White Dwarfs?
• UVIT Open Cluster Study. I. Detection of a White Dwarf Companion to a Blue Straggler in M67: Evidence of Formation through Mass Transfer
• Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries
• The Discovery of a Companion to the Lowest Mass White Dwarf
• Infrared Spectroscopy of Symbiotic Stars. VII. Binary Orbit and Long Secondary Period Variability of CH Cygni
• A new extremely low-mass white dwarf in the NLTT catalogue
• LP 400-22, A very low-mass and high-velocity white dwarf
• Orbital properties of an unusually low-mass sdB star in a close binary system with a white dwarf
• SOPHIE velocimetry of Kepler transit candidates. I. Detection of the low-mass white dwarf KOI-74b
• Maximal Masses of White Dwarfs for Polytropes in $R^2$ Gravity and Theoretical Constraints
• The Runaway White Dwarf LP400-22 Has a Companion
• Studies of RR Lyrae Variables in Binary Systems. I.: Evidence of a Trimodal Companion Mass Distribution
• The Clusters AgeS Experiment (CASE). I. V209 omega Cen - An Eclipsing Post-Common Envelope Binary in the Globular Cluster omega Cen
• A Radio Search For Pulsar Companions To SDSS Low-Mass White Dwarfs
• The Mass Distribution of Companions to Low-Mass White Dwarfs
• A search for radio pulsars around low-mass white dwarfs
• Quantum Liquid Signatures in Dwarf Stars
• Effective Field Theory for Quantum Liquid in Dwarf Stars
• Chandra X-ray Constraints on the Candidate Ca-rich Gap Transient SN 2016hnk
• Quantitative spectral analysis of the sdB star HD 188112: a helium-core white dwarf progenitor
• Oscillations and tidal deformations of crystallized white dwarfs
• The first OGLE-discovered ultracompact X-ray binary is an intermediate polar
• Strongly Coupled Condensate of High Density Matter
• Two Component Charged Condensate in White Dwarfs
• Detecting White Dwarf Binary Mergers with Gravitational Waves
• Was there a (super)nova in 1408?