2010A&A...513A..12R


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.14CEST22:18:07

2010A&A...513A..12R - Astronomy and Astrophysics, volume 513, A12-12 (2010/4-1)

Quiescent and flaring X-ray emission from the nearby M/T dwarf binary SCR 1845-6357.

ROBRADE J., POPPENHAEGER K. and SCHMITT J.H.M.M.

Abstract (from CDS):

X-ray emission is an important diagnostics to study magnetic activity in very low mass stars that are presumably fully convective and have an effectively neutral photosphere. We investigate an XMM-Newton observation of SCR 1845-6357, a nearby, ultracool M8.5/T5.5 dwarf binary. The binary is unresolved in the XMM detectors, but the X-ray emission is very likely from the M8.5 dwarf. We compare its flaring emission to those of similar very low mass stars and additionally present an XMM observation of the M8 dwarf VB 10. We detect quasi-quiescent X-ray emission from SCR 1845-6357 at soft X-ray energies in the 0.2-2.0keV band, as well as a strong flare with a count rate increase of a factor of 30 and a duration of only 10 min. The quasi-quiescent X-ray luminosity of logLX=26.2erg/s and the corresponding activity level of logLX/Lbol=-3.8 point to a fairly active star. Coronal temperatures of up to 5MK and frequent minor variability support this picture. During the flare, which is accompanied by a significant brightening in the near-UV, plasma temperatures of 25-30 MK are observed and an X-ray luminosity of LX=8x1027erg/s is reached. The source SCR 1845-6357 is a nearby, very low mass star that emits X-rays at detectable levels in quasi-quiescence, implying the existence of a corona. The high activity level, coronal temperatures and the observed large flare point to a rather active star, despite its estimated age of a few Gyr.

Abstract Copyright:

Journal keyword(s): stars: activity - stars: coronae - stars: individual: SCR 1845-6357 - stars: low-mass - brown dwarfs - X-rays: stars

Simbad objects: 9

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Number of rows : 9

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 LP 412-31 LM* 03 20 59.7107396327 +18 54 22.772041176   20.5 18.881 16.904 14.484 M8V 110 0
2 LP 666-9 LM* 08 53 36.1607609203 -03 29 32.201339067     18.959 16.781 14.487 M9Ve 222 0
3 1RXS J115928.5-524717 LM* 11 59 27.3607245322 -52 47 18.910528784       16.617 14.49 M9Ve 24 0
4 NAME Kelu-1 BD* 13 05 40.1737206066 -25 41 05.830344467         16.85 L2+L3.5 236 0
5 SCR J1845-6357 LM* 18 45 05.2506866871 -63 57 47.458544682     17.40 14.99 12.46 M8.5V 59 1
6 DENIS J184507.7-635740 * 18 45 07.7283593731 -63 57 40.717412458         17.79 ~ 1 0
7 USNO-B1.0 0260-00695925 * 18 45 09.0957436271 -63 57 50.935646388   19.6   19.1   ~ 1 0
8 VB 10 Er* 19 16 57.6103282334 +05 09 01.588675251     17.30     M8V 435 1
9 * eps Ind PM* 22 03 21.6542294981 -56 47 09.537018193   5.75 4.69     K5V 476 0

    Equat.    Gal    SGal    Ecl

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2020.07.14-22:18:07

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