Twelve new substellar members in Taurus. Clues for substellar formation models

    Authors

    S. Guieu; J. L. Monin; C. Dougados; E. Magnier;E. L. Martin

    Comments

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    Abbreviated Journal Title

    Astro. Nachr.

    Keywords

    stars : low-mass, brown dwarfs; stars : late-type; stars : luminosity; function, mass function; stars : pre-main sequence; INITIAL MASS FUNCTION; STAR-FORMING REGION; MAIN-SEQUENCE STARS; BROWN; DWARFS; IC 348; AURIGA; EVOLUTION; CLUSTER; ORIGIN; CLOUD; Astronomy & Astrophysics

    Abstract

    Recent studies of the substellar population in the Taurus cloud have revealed a deficit of brown dwarfs compared to the Trapezium cluster population (Briceno 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 similar or equal to 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.

    Journal Title

    Astronomische Nachrichten

    Volume

    326

    Issue/Number

    10

    Publication Date

    1-1-2005

    Document Type

    Article; Proceedings Paper

    Language

    English

    First Page

    1068

    Last Page

    1071

    WOS Identifier

    WOS:000234434000047

    ISSN

    0004-6337

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