Title

Twelve New Substellar Members In Taurus. Clues For Substellar Formation Models

Keywords

Stars: late-type; Stars: low-mass, brown dwarfs; Stars: luminosity function, mass function; Stars: pre-main sequence

Abstract

Recent studies of the substellar population in the Taurus cloud have revealed a deficit of brown dwarfs compared to the Trapezium cluster population (Briceño et al. 1998; Luhman 2000; Luhman et al. 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 deg 2, 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 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. ©2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Publication Date

12-1-2005

Publication Title

Astronomische Nachrichten

Volume

326

Issue

10

Number of Pages

1068-1071

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1002/asna.200510476

Socpus ID

29844431502 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/29844431502

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