A near-IR spectroscopic search for very-low-mass cool companions to notable DA white dwarfs

Abstract

We have undertaken a detailed near-IR spectroscopic analysis of eight notable white dwarfs, predominantly of southern declination. In each case the spectrum failed to reveal compelling evidence for the presence of a spatially unresolved, cool, late-type companion. Therefore, we have placed an approximate limit on the spectral-type of a putative companion to each degenerate. From these limits we conclude that if GD659, GD50, GD71 or WD2359-434 possesses an unresolved companion then most probably it is substellar in nature (M<0.072Msun). Furthermore, any spatially unresolved late-type companion to RE J0457-280, RE J0623-374, RE J0723-274 or RE J2214-491 most likely has M<0.082Msun. These results imply that if weak accretion from a nearby late-type companion is the cause of the unusual photospheric composition observed in a number of these degenerates then the companions are of very low mass, beyond the detection thresholds of this study. Furthermore, these results do not contradict a previously noted deficit of very-low-mass stellar and brown dwarf companions to main sequence F,G,K and early-M type primaries (a<1000AU).

arXiv commentAccepted for publication in MNRAS 9-12-04

References in corpus (22)

• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945
• Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs
• L' and M' Photometry of Ultracool Dwarfs
• Towards Spectral Classification of L and T Dwarfs: Infrared and Optical Spectroscopy and Analysis
• The NIRSPEC Brown Dwarf Spectroscopic Survey. I. Low-Resolution Near-Infrared Spectra
• Infrared Spectra and Spectral Energy Distributions of Late-M- and L-Dwarfs
• Infrared Parallaxes for Methane T dwarfs
• Near-Infrared Classification Spectroscopy: H-band Spectra of Fundamental MK Standards
• Substellar Companions to Main Sequence Stars: No Brown Dwarf Desert at Wide Separations
• Discovery of kilogauss magnetic fields in three DA white dwarfs
• A Possible Brown Dwarf Companion to the White Dwarf GD1400
• Radial velocity measurements of white dwarfs
• Near-Infrared Classification Spectroscopy: J-Band Spectra of Fundamental MK Standards
• Heavy element abundance patterns in hot DA white dwarfs
• The Formation of Cataclysmic Variables with Brown Dwarf Secondaries
• Cool Companions to White Dwarfs from the 2MASS Second Incremental Data Release
• A comparison of DA white dwarf temperatures and gravities from FUSE Lyman line and ground-based Balmer line observations
• Cool Companions to Hot White Dwarfs
• Equilibrium abundances in hot DA white dwarfs as derived from self-consistent diffusion models I. Analysis of spectroscopic EUVE data
• Spectroscopic Discovery of Brown Dwarf-like Secondary Stars in the Cataclysmic Variables LL And and EF Eri
• Near-Infrared Spectroscopy of Brown Dwarfs: Methane and the Transition between the L and T Spectral Types
• Mid Infrared Observations of Van Maanen 2: No Substellar Companion

Cited by in corpus (37)

• Survival of a brown dwarf after engulfment by a red giant star
• Spitzer IRAC Observations of White Dwarfs. I. Warm Dust at Metal-Rich Degenerates
• The ESO supernovae type Ia progenitor survey (SPY)
• Atmospheres of Brown Dwarfs
• Detection limits for close eclipsing and transiting sub-stellar and planetary companions to white dwarfs in the WASP survey
• White dwarfs in the UKIDSS Large Area Survey: The Substellar Companion Fraction
• Measuring M dwarf Winds with DAZ White Dwarfs
• Discovery of a redshift 6.13 quasar in the UKIRT Infrared Deep Sky Survey
• NLTT5306: The shortest Period Detached White Dwarf + Brown Dwarf Binary
• White Dwarf - Red Dwarf Systems Resolved with the Hubble Space Telescope. II. Full Snapshot Survey Results
• Two white dwarfs in ultrashort binaries with detached, eclipsing, likely substellar companions detected by K2
• Close detached white dwarf + brown dwarf binaries: further evidence for low values of the common envelope efficiency
• Discovery of a T dwarf + white dwarf binary system
• A near-infrared spectroscopic detection of the brown dwarf in the post common envelope binary WD0137-349
• The nature of the close magnetic white dwarf + probable brown dwarf binary SDSS J121209.31+013627.7
• Cool Companions to White Dwarf Stars from the Two Micron All Sky Survey All Sky Data Release
• Astrophysical false positives in direct imaging for exoplanets: a white dwarf close to a rejuvenated star
• A Near-Infrared Spectroscopic Study of the Accreting Magnetic White Dwarf SDSS J121209.31+013627.7 and its Substellar Companion
• Disks and Planets Around Massive White Dwarfs
• PHL 5038: A spatially resolved white dwarf + brown dwarf binary
• The DODO Survey II: A Gemini Direct Imaging Search for Substellar and Planetary Mass Companions around Nearby Equatorial and Northern Hemisphere White Dwarfs
• Infrared Photometric Analysis of White Dwarfs from The Two Micron All Sky Survey and the Spitzer Space Telescope
• Cool Customers in the Stellar Graveyard IV: Spitzer Search for Mid-IR excesses Around Five DAs
• WIRED for EC: New White Dwarfs with $\text{WISE}$ Infrared Excesses and New Classification Schemes from the Edinburgh-Cape Blue Object Survey
• Mid-Infrared Observations of the White Dwarf Brown Dwarf Binary GD 1400
• Discovery of a widely separated UCD-WD binary
• The "DODO" survey I: limits on ultra-cool substellar and planetary-mass companions to van Maanen's star (vMa 2)
• Cyclic period oscillation of the eclipsing dwarf nova DV UMa
• A massive white dwarf member of the Coma Berenices Open Cluster
• A near-IR spectrum of the DO white dwarf RE J0503-285
• Photospheric phosphorus in the FUSE spectra of GD71 and two similar DA white dwarfs
• Circumstellar Disks at White Dwarfs: Observations
• Near-infrared spectroscopy of the very low mass companion to the hot DA white dwarf PG1234+482
• Low Mass Companions to White Dwarfs
• Gaia white dwarfs with infrared excess I. The 100 pc catalogue
• Phase-resolved Hubble Space Telescope WFC3 Spectroscopy of Weakly-Irradiated Brown Dwarf GD 1400 and Energy Redistribution-Irradiation Trends in Six WD$-$BD Binaries
• Fates of the sub-stellar objects (FOSSO) I. Fates of the known brown dwarfs in main-sequence--BD binaries