Guieu, S.; Monin, J.-L.; Dougados, C.; Magnier, E.; Martín, E. L.
Referencia bibliográfica
Astronomische Nachrichten, Vol.326, Issue 10, p.1068-1071
Fecha de publicación:
12
2005
Número de citas
2
Número de citas referidas
1
Descripción
Recent studies of the substellar population in the Taurus cloud have
revealed a deficit of brown dwarfs compared to the Trapezium cluster
population (citealt{Briceno-1998,Luhman-2000,Luhman-2003a,Luhman-2004})
However, these works have concentrated on the highest stellar density
regions of the Taurus cloud. We have performed a large scale optical
survey of this region, covering a total area of ≃ 28
deg2, and encompassing the densest parts of the cloud as well
as their surroundings. In this paper, we present optical spectroscopic
follow-up observations of 97 photometrically selected potential new
low-mass Taurus members. We derive spectral types, visual absorption and
luminosity class estimates and discuss our criteria to assess Taurus
membership. These observations reveal 5 new very low mass stars (VLMs)
and 12 new Brown Dwarfs (BDs) on the Taurus cloud. We derive a new
substellar to stellar ratio in Taurus of mathcal{R}ss =0.23
± 0.05. This revisited ratio appears consistent with the value of
0.26 ± 0.04 previously derived in the Trapezium cluster under
similar assumptions. We find indications that the relative numbers of
BDs with respect to stars is decreased by a factor 2 in the central
regions of the aggregates with respect to the more distributed
population.