Title

INTERMEDIATE RESOLUTION NEAR-INFRARED SPECTROSCOPY OF 36 LATE M DWARFS

Authors

Authors

R. Deshpande; E. L. Martin; M. M. Montgomery; M. R. Z. Osorio; F. Rodler; C. del Burgo; N. P. Bao; Y. Lyubchik; R. Tata; H. Bouy;Y. Pavlenko

Comments

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Abbreviated Journal Title

Astron. J.

Keywords

brown dwarfs; planetary systems; stars: fundamental parameters; stars:; low-mass; stars: rotation; techniques: radial velocities; LOW-MASS STARS; YOUNG BROWN DWARFS; DIGITAL SKY SURVEY; M-CIRCLE-PLUS; ULTRACOOL DWARFS; ROTATIONAL VELOCITIES; COOL NEIGHBORS; VB 10; CHROMOSPHERIC ACTIVITY; DETECTING PLANETS; Astronomy & Astrophysics

Abstract

We present observations of 36 late M dwarfs obtained with the Keck II/NIRSPEC in the J band at a resolution of similar to 20,000. We have measured projected rotational velocities, absolute radial velocities, and pseudo-equivalent widths of atomic lines. Twelve of our targets did not have previous measurements in the literature. For the other 24 targets, we confirm previously reported measurements. We find that 13 stars from our sample have v sin i below our measurement threshold (12 km s(-1)) whereas four of our targets are fast rotators (v sin i > 30 km s(-1)). As fast rotation causes spectral features to be washed out, stars with low projected rotational velocities are sought for radial velocity surveys. At our intermediate spectral resolution, we have confirmed the identification of neutral atomic lines reported in McLean et al. We also calculated pseudo-equivalent widths of 12 atomic lines. Our results confirm that the pseudo-equivalent width of K I lines is strongly dependent on spectral types. We observe that the pseudo-equivalent width of Fe i and Mn I lines remains fairly constant with later spectral type. We suggest that these lines are particularly suitable for deriving metallicities for late M dwarfs.

Journal Title

Astronomical Journal

Volume

144

Issue/Number

4

Publication Date

1-1-2012

Document Type

Article

Language

English

First Page

12

WOS Identifier

WOS:000308919300009

ISSN

0004-6256

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