2007A&A...468..557G


Query : 2007A&A...468..557G

2007A&A...468..557G - Astronomy and Astrophysics, volume 468, 557-562 (2007/6-3)

A U-band survey of brown dwarfs in the Taurus molecular cloud with the XMM-Newton optical/UV monitor.

GROSSO N., AUDARD M., BOUVIER J., BRIGGS K.R. and GUEDEL M.

Abstract (from CDS):

We aim to characterize the U-band variability of young brown dwarfs in the Taurus Molecular Cloud and discuss its origin. We used the XMM-Newton Extended Survey of the Taurus Molecular Cloud, where a sample of 11 young bona fide brown dwarfs (spectral type later than M6) were observed simultaneously in X-rays with XMM-Newton and in the U-band with the XMM-Newton Optical/UV Monitor (OM). We obtained upper limits to the U-band emission of 10 brown dwarfs (U≥19.6-20.6mag), whereas 2MASSJ04141188+2811535 was detected in the U-band. Remarkably, the magnitude of this brown dwarf increased regularly from U∼19.5mag at the beginning of the observation, peaked 6h later at U∼18.4mag, and then decreased to U∼18.65mag in the next 2h. The first OM U-band measurement is consistent with the quiescent level observed about one year later thanks to ground follow-up observations. This brown dwarf was not detected in X-rays by XMM-Newton during the OM observation. We discuss the possible sources of U-band variability for this young brown dwarf, namely a magnetic flare, non-steady accretion onto the substellar surface, and rotational modulation of a hot spot. We conclude that this event is related to accretion from a circumsubstellar disk, where the mass accretion rate was about a factor of 3 higher than during the quiescent level.

Abstract Copyright:

Journal keyword(s): stars: low-mass, brown dwarfs - stars: individual: 2MASSJ04141188+2811535 - X-rays: stars - ISM: individual objects: the Taurus Molecular Cloud

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 2MASS J04141188+2811535 Y*O 04 14 11.8840810320 +28 11 53.409534000 18.72         M6e 53 0
2 HD 283447 Or* 04 14 12.9261150912 +28 12 12.359055168 13.17 12.07 10.68 9.45 8.67 K3Ve 395 0
3 2MASS J04215450+2652315 TT* 04 21 54.5268118920 +26 52 31.344496428           M8.5 28 0
4 2MASS J04221332+1934392 TT* 04 22 13.3181762256 +19 34 39.261481392           M8.5 28 0
5 [BLH2002] KPNO-Tau 4 BD* 04 27 27.9991044840 +26 12 05.085665388     24.722 20.54 18.75 L0 68 0
6 [BLH2002] KPNO-Tau 5 LM* 04 29 45.6727447200 +26 30 46.560493080     19.690 19.10 15.08 M7.5Ve 53 0
7 [BLH2002] KPNO-Tau 6 BD* 04 30 07.2454086048 +26 08 20.709374568     22.292 20.56 17.90 M8.5Ve 58 0
8 [BLH2002] KPNO-Tau 7 LM* 04 30 57.2037785664 +25 56 39.548804460     22.068   17.16 M8Ve 53 0
9 2MASS J04325026+2422115 Y*O 04 32 50.2670582784 +24 22 11.662393728         18.79 M7.5 37 0
10 [BLH2002] KPNO-Tau 9 LM* 04 35 51.4276211184 +22 49 11.851904748     24.918   18.76 M8.5V 43 0
11 2MASS J04361038+2259560 Y*O 04 36 10.3843111944 +22 59 55.998727368     22.520   16.81 M8Ve 51 0
12 2MASS J04390396+2544264 Y*O 04 39 03.9609205920 +25 44 26.345775480       18.40 15.40 M7IVe 56 0
13 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3926 0

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2022.05.27-23:45:45

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