SIMBAD references

2008MNRAS.388..838D - Mon. Not. R. Astron. Soc., 388, 838-848 (2008/August-1)

Discovery of a widely separated ultracool dwarf-white dwarf binary.

DAY-JONES A.C., PINFIELD D.J., NAPIWOTZKI R., BURNINGHAM B., JENKINS J.S., JONES H.R.A., FOLKES S.L., WEIGHTS D.J. and CLARKE J.R.A.

Abstract (from CDS):

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 3650-5250au at an estimated distance of 41-59pc, making it the widest known system of this type. Spectroscopy reveals 2MASS J0030-3740 is a DA white dwarf with Teff= 7600±100K, log(g) = 7.79-8.09 and MWD= 0.48-0.65M. We spectroscopically type the ultracool dwarf companion (2MASS J0030-3739) as M9±1 and estimate a mass of 0.07-0.08M,Teff= 2000-2400K 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 >1.94Gyr (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.

Abstract Copyright: © 2008 The Authors. Journal compilation © 2008 RAS

Journal keyword(s): binaries: general - stars: low-mass, brown dwarfs - white dwarfs

Nomenclature: Table 2: [DPN2008] UCDc-N (Nos 1 to 8), [DPN2008] WDc-N (Nos 1 to 8).

Simbad objects: 37

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