1999ApJ...519..345L


Query : 1999ApJ...519..345L

1999ApJ...519..345L - Astrophys. J., 519, 345-353 (1999/July-1)

A 2MASS ultracool M dwarf observed in a spectacular flare.

LIEBERT J., KIRKPATRICK J.D., REID I.N. and FISHER M.D.

Abstract (from CDS):

2MASSW J0149090+295613 (hereafter 2M0149) is unique among the very late M/L dwarf counterparts to Two Micron All Sky Survey (2MASS) point sources in having shown, in the first set of spectra taken on 1997 December 7, a diverse emission-line spectrum at red wavelengths, which features an Hα equivalent width of 300 Å. On four repeat observations, however, the spectrum was that of a more ordinary dMe object, albeit with a late spectral type of M9.5 V. Our interpretation is that the object underwent an extreme magnetic flare event. The continuum flux at the short-wavelength end of the spectrum was also several times stronger during the apparent flare than in quiescence. Comparison is made with midtype M dwarfs of higher mass that have undergone strong flares, and with another known M9.5 emission-line object PC 0025+0047. The 2MASS object adds to the evidence that magnetic dynamo eruptions may release more energy relative to Lbol as the stellar mass decreases; if the total flare luminosity scales with Hα in the same way as a well-observed event of the middle M dwarf AD Leo, 2M0149 may have had a flare luminosity that approached or exceeded its quiescent Lbol during the brief impulse phase. In contrast, its quiescent state shows an unremarkable level of chromospheric activity, which leads us to question whether it is unique at all; rather, it may be that many of the ultracool M and L dwarfs found by the Deep Near-Infrared Survey (DENIS) and 2MASS undergo similar flares.

Abstract Copyright:

Journal keyword(s): Stars: Emission-Line, Be - Stars: Flare - stars: individual (2MASSW J0149090+295613) - Stars: Late-Type

Nomenclature: 2MASSW JHHMMSSs+DDMMSS N=1.

Simbad objects: 12

goto Full paper

goto View the references in ADS

Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 V* DY Psc BY* 00 24 24.6317407560 -01 58 19.954412004     19.42 17.301 15.022 M9.5V 199 1
2 PC 0025+0447 LM* 00 27 41.9817343344 +05 03 41.691766608           M9.5e 73 0
3 G 272-61B Er* 01 39 01.6377185550 -17 57 01.001240728           M6V 833 0
4 2MASSW J0149090+295613 LM* 01 49 09.0028348631 +29 56 12.511555579           M9.5V 53 0
5 LP 944-20 LM* 03 39 35.2523500210 -35 25 43.641996333     18.69 16.39 13.288 M9.5Ve 280 0
6 LP 666-9 LM* 08 53 36.1604798120 -03 29 32.197505547     18.959 16.781 14.487 M9Ve 239 0
7 BD+20 2465 Er* 10 19 36.2808181226 +19 52 12.010446571   10.82 9.52 9.19   dM3 1251 0
8 LP 732-94 LM* 11 21 49.1708652037 -13 13 08.693807585     19.57     M8.5V 126 0
9 LP 271-25 LM* 14 28 43.2275214164 +33 10 39.259309081   21.2   17.8   M9Ve 239 0
10 VB 8 Er* 16 55 35.2557374336 -08 23 40.753073075   18.7 16.916 14.566 12.24 M7Ve 415 0
11 VB 10 Er* 19 16 57.6109547886 +05 09 01.600923413     17.30     M8V 464 1
12 V* AF Psc Er* 23 31 44.9255654328 -02 44 39.537845376   15.7 14.43 13.3   M4.5 54 0

To bookmark this query, right click on this link: simbad:objects in 1999ApJ...519..345L and select 'bookmark this link' or equivalent in the popup menu


2022.12.08-14:39:41

© Université de Strasbourg/CNRS

    • Contact