Ultracool Companions to White Dwarfs

Steele, P. R.; Burleigh, M. R.; Barstow, M. A.; Jameson, R. F.; Dobbie, P. D.

doi:10.1063/1.3527847

Cited by 2 publications

(1 citation statement)

References 102 publications

(166 reference statements)

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“…There have been several searches to find UCD companions to WDs. Despite this, only a small number of detached UCD–WD binaries have been identified; GD 165 (DA + L4) (Zuckerman & Becklin 1992), GD 1400 (DA+L6/7) (Farihi & Christopher 2004; Dobbie et al 2005), WD 0137−349 (DA+L8) (Maxted et al 2006; Burleigh et al 2006a) and PG1234+482 (DA+L0) (Steele et al 2007; Mullally et al 2007). The two components in GD 165 are separated by 120 au, the separation of the components in GD 1400 and PG 1234+482 are currently unknown and WD 0137−349 is a close binary (semimajor axis a = 0.65 R ⊙ ).…”

Section: Introductionmentioning

confidence: 99%

Discovery of a widely separated ultracool dwarf–white dwarf binary

Day-Jones¹,

Pinfield²,

Napiwotzki³

et al. 2008

Monthly Notices of the Royal Astronomical Society

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We present the discovery of the widest known ultracool dwarf–white dwarf binary. This binary is the first spectroscopically confirmed widely separated system from our target sample. We have used the Two‐Micron All‐Sky Survey (2MASS) and SuperCOSMOS archives in the southern hemisphere, searching for very widely separated ultracool dwarf–white dwarf binaries, and find one common proper motion system, with a separation of 3650–5250 au at an estimated distance of 41–59 pc, making it the widest known system of this type. Spectroscopy reveals 2MASS J0030−3740 is a DA white dwarf with Teff= 7600 ± 100 K, log(g) = 7.79–8.09 and MWD= 0.48–0.65 M⊙. We spectroscopically type the ultracool dwarf companion (2MASS J0030−3739) as M9 ± 1 and estimate a mass of 0.07–0.08 M⊙, Teff= 2000–2400 K and log(g) = 5.30–5.35, placing it near the mass limit for brown dwarfs. We estimate the age of the system to be >1.94 Gyr (from the white dwarf cooling age and the likely length of the main‐sequence lifetime of the progenitor) and suggest that this system and other such wide binaries can be used as benchmark ultracool dwarfs.

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Section: Introductionmentioning

confidence: 99%

Discovery of a widely separated ultracool dwarf–white dwarf binary

Day-Jones¹,

Pinfield²,

Napiwotzki³

et al. 2008

Monthly Notices of the Royal Astronomical Society

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Discovery of a resolved white dwarf–brown dwarf binary with a small projected separation: SDSS J222551.65+001637.7AB

French

Casewell

Dupuy

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We present the confirmation of SDSS J222551.65+001637.7AB as a closely separated, resolved, white dwarf-brown dwarf binary. We have obtained spectroscopy from GNIRS and seeing-limited Ks-band imaging from NIRI on Gemini North. The target is spatially resolved into its constituent components: a 10926 ± 246 K white dwarf, with log g = 8.214 ± 0.168 and a mass of 0.66$^{+0.11}_{-0.06}$ M⊙, and an L4 brown dwarf companion, which are separated by 0.9498 ± 0.0022″. We derive the fundamental properties of the companion from the Sonora-Bobcat evolutionary models, finding a mass of 25 − 53 MJup and a radius of 0.101 − 0.128 R⊙ for the brown dwarf, at a confidence level of 1σ. We use wdwarfdate to determine the age of the binary as $1.97^{+4.41}_{-0.76}$ Gyr. A kinematic analysis shows that this binary is likely a member of the thick disc. The distance to the binary is 218$^{+14}_{-13}$ pc, and hence the projected separation of the binary is 207$^{+13}_{-12}$ AU. Whilst the white dwarf progenitor was on the main sequence the binary separation would have been 69 ± 5 AU. SDSS J222551.65+001637.7AB is the third closest spatially resolved white dwarf-brown dwarf binary after GD 165AB and PHL 5038AB.

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Ultracool Companions to White Dwarfs

Cited by 2 publications

References 102 publications

Discovery of a widely separated ultracool dwarf–white dwarf binary

Discovery of a widely separated ultracool dwarf–white dwarf binary

Discovery of a resolved white dwarf–brown dwarf binary with a small projected separation: SDSS J222551.65+001637.7AB

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