Bibcode
Scholz, R.-D.; McCaughrean, M. J.; Lodieu, N.; Kuhlbrodt, B.
Referencia bibliográfica
Astronomy and Astrophysics, v.398, p.L29-L33 (2003)
Fecha de publicación:
2
2003
Revista
Número de citas
139
Número de citas referidas
125
Descripción
We have identified a new early T dwarf only 3.6 pc from the Sun, as a
common proper motion companion (separation 1459 AU) to the K5V star
varepsilon Indi (HD 209100). As such, varepsilon Indi B is one of the
highest proper motion sources outside the solar system ( ~ 4.7
arcsec/yr), part of one of the twenty nearest stellar systems, and the
nearest brown dwarf to the Sun. Optical photometry obtained from the
SuperCOSMOS Sky Survey was combined with approximate infrared photometry
from the 2MASS Quicklook survey data release, yielding colours for the
source typical of early T dwarfs. Follow-up infrared spectroscopy using
the ESO NTT and SOFI confirmed its spectral type to be T2.5 +/- 0.5.
With Ks=magnit {11}{2}, varepsilon Indi B is 1.7 mag
brighter than any previously known T dwarf and 4 mag brighter than the
typical object in its class, making it highly amenable to detailed
study. Also, as a companion to a bright nearby star, it has a precisely
known distance (3.626+/- 0.009 pc) and relatively well-known age (0.8-2
Gyr), allowing us to estimate its luminosity as log L/
Lsun,=-4.67, its effective temperature as 1260 K, and its
mass as ~ 40-60 MJup. varepsilon Indi B represents an
important addition to the census of the Solar neighbourhood and, equally
importantly, a new benchmark object in our understanding of substellar
objects.
Based on data from the SuperCOSMOS Sky Surveys and observations
collected with the ESO NTT, La Silla, Chile.