2003A&A...408..663Z


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.19CET16:50:40

2003A&A...408..663Z - Astronomy and Astrophysics, volume 408, 663-673 (2003/9-3)

Photometric variability of a young, low-mass brown dwarf.

ZAPATERO OSORIO M.R., CABALLERO J.A., BEJAR V.J.S. and REBOLO R.

Abstract (from CDS):

We report differential I-band and J-band photometry of S Ori 45, a cool (spectral type M8.5), young (1-8Myr) brown dwarf of the σOrionis cluster with a likely mass estimated at around 20 times the mass of Jupiter. We detect variability (amplitudes ranging from 34 to 81mmag) and observe a modulation at a period of 2.5-3.6h in both optical and near-infrared light curves. The most recent optical data set, however, presents a modulation at the very short period of 46.4±1.5min, which remains a mystery. The origin of the 2.5-3.6h modulation is analyzed in terms of various scenarios: inhomogeneous features (dust clouds or magnetically induced dark spots) co-rotating with the object's surface, and presence of an unseen very low-mass companion that is steadily transferring mass to the primary. Because of the very young age of the object and its persistent strong Hα emission, the possible presence of an accreting disk is also discussed. If the period of a few hours is related to rotation, our results suggest that σOrionis low-mass brown dwarfs are rotating faster than more massive cluster brown dwarfs at a rate consistent with their theoretically inferred masses and radii, implying that all of these objects have undergone similar angular momentum evolution.

Abstract Copyright:

Journal keyword(s): stars: low mass, brown dwarfs - stars: rotation - stars: pre-main sequence - stars: formation

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* DY Psc BY* 00 24 24.6343271916 -01 58 19.968960103     19.42 17.301 15.022 M9.5V 192 1
2 [BZR99] S Ori 33 * 05 36 58.0790338638 -02 35 19.451241597         17.08 ~ 11 0
3 [BZR99] S Ori 31 Y*O 05 38 20.8779121749 -02 46 13.330061031         17.25 M4.0 23 0
4 V* V2729 Ori Or* 05 38 25.57752 -02 48 37.0224   21.09 24.40 22.07 19.54 M8.5 31 0
5 NAME sigma Orionis Cluster MGr 05 38 42 -02 36.0           ~ 496 0
6 LSPM J0746+2000 BD* 07 46 42.49536 +20 00 32.6124       17.9 15.034 L0+L1.5 172 1
7 2MASS J12373919+6526148 BD* 12 37 39.19632 +65 26 14.8092           T6.5 63 0

    Equat.    Gal    SGal    Ecl

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2021.01.19-16:50:40

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