Title

Observations of ultracool dwarfs with ULTRACAM on the VLT: a search for weather

Authors

Authors

S. P. Littlefair; V. S. Dhillon; T. R. Marsh; T. Shahbaz;E. L. Martin

Comments

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Abbreviated Journal Title

Mon. Not. Roy. Astron. Soc.

Keywords

stars : individual : Kelu-1; stars : individual : 2MASS 1300+1912; stars; : individual : 2MASS 2057-0252; stars : individual : DENIS 1441-0945; stars : low-mass; brown dwarfs; BROWN DWARFS; PHOTOMETRIC VARIABILITY; ATMOSPHERES; KELU-1; STARS; DUST; MULTIPLICITY; Astronomy & Astrophysics

Abstract

We present multicolour photometry of four-field ultracool dwarfs with the triple-beam photometer ULTRACAM. Data were obtained simultaneously in the Sloan-g' band and a specially designed narrow-band Na I filter. The previously reported 1.8-h period of Kelu-1 is here recovered in the g' band, but the lack of any significant variability in the Na I light of this object precludes any conclusion as to the cause of the variability. 2MASS 2057-0252 and DENIS 1441-0945 show no convincing evidence for variability. 2MASS 1300+1912, on the other hand, shows good evidence for gradual trends in both bands at the 5 per cent level. These trends are anticorrelated at a high level of significance, a result, which is incompatible with models of star-spot induced variability. It would seem likely that dust-cloud 'weather' is responsible for the short-term variability in this object.

Journal Title

Monthly Notices of the Royal Astronomical Society

Volume

370

Issue/Number

3

Publication Date

1-1-2006

Document Type

Article

Language

English

First Page

1208

Last Page

1212

WOS Identifier

WOS:000239336400009

ISSN

0035-8711

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