2004A&A...426..577M


C.D.S. - SIMBAD4 rel 1.7 - 2021.04.12CEST03:25:43

2004A&A...426..577M - Astronomy and Astrophysics, volume 426, 577-585 (2004/11-1)

The shortest period M dwarf eclipsing system BW3 V38. II. Determination of absolute elements.

MACERONI C. and MONTALBAN J.

Abstract (from CDS):

The spectroscopic data for the short-period (0.1984d) eclipsing binary V38, discovered by the OGLE micro-lensing team in Baade's Window field BW3, are analyzed. Radial velocity curves are derived from mid-resolution spectra obtained with EMMI-NTT at ESO - La Silla, and a simultaneous solution of the existing light curve by OGLE and of the new radial velocity curves is obtained. The system is formed by almost twin M3e dwarf components that are very close, but not yet in contact. The spectra of both dwarfs show signatures of the presence of strong chromospheres. Spectroscopy definitely confirms, therefore, what was suggested on the basis of photometry: BW3 V38 is indeed a unique system, as no other similar binary with M components and in such a tight orbit is known. Within the limits posed by the relatively large errors, due to the combined effect of system faintness and of the constraints on exposure time, the derived physical parameters seem to agree with the relations obtained from the other few known eclipsing binaries with late type components (which indicate a discrepancy between the available evolutionary models and the data at ∼10% level). A possible explanation is the presence of strong magnetic fields and fast rotation (that applies to the BW3 V38 case as well). A simple computation of the system secular evolution by angular momentum loss and spin-orbit synchronization shows that the evolution of a system with M dwarf components is rather slow, and indicates as well a possible reason why systems similar to BW3 V38 are so rare.

Abstract Copyright:

Journal keyword(s): stars: binaries: close - stars: binaries: eclipsing - stars: late-type - stars: fundamental parameters - stars: individual: OGLE BW3 V38

Simbad objects: 8

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Number of rows : 8

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 HD 27130 EB* 04 17 38.9458416476 +16 56 52.210019080   9.075 8.315 8.79   G8V 234 0
2 Cl Melotte 25 OpC 04 26 54.00 +15 52 00.0           ~ 2752 0
3 V* YY Gem BY* 07 34 37.4475372002 +31 52 10.181030942 11.60 10.56 9.27 7.69 6.67 M0.5VeFe-2 827 0
4 V* CU Cnc Er* 08 31 37.5740891049 +19 23 39.398696822   12.83 11.809 11.592   M5Ve 204 0
5 V* CM Dra BY* 16 34 20.3299130309 +57 09 44.365524588   14.50 12.87 10.85 9.26 M4.5V 410 0
6 OGLE BW3 V38 EB* 18 04 44.2034110073 -30 09 05.505472642     18.300   16.3335 ~ 39 0
7 Ross 154 Er* 18 49 49.3638007809 -23 50 10.453568573 13.528 12.19 10.43 10.23 7.703 M3.5Ve 333 0
8 HD 190007 BY* 20 02 47.0455912903 +03 19 34.264805769   8.60   6.8   K5V 206 0

    Equat.    Gal    SGal    Ecl

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2021.04.12-03:25:43

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