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H-alpha photometry of dwarf K and M stars - Chromospheric activity
H-alpha photometry of 118 K and M dwarfs are presented, with H-alphaequivalent width measures accurate to about 0.05 A. The data arecombined with the spectroscopic surveys of Stauffer and Hartmann (1986)and Fleming et al. (1988) to study the main features of thechromospheric activity versus mass relation for low-mass stars. An upperbound to the H-alpha equivalent width is found to be a function of themass relation (R-I). H-alpha luminosities and surface fluxes arecalculated for active stars, showing that both quantities generallydecline with R-I. The upper bound to the fraction of a star's bolometricluminosity, however, is independent of R-I. The results suggest that thechromospheres of most dMe stars with R-I less than 1.1 are in anactivity-saturated state. Also, H-alpha variability, probably due toflares, is detected in several stars.
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| Liste et classification d'étoiles nouvelles M,S,C et à émission
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Membro dei seguenti gruppi:
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Osservazione e dati astrometrici
| Costellazione: | Andromeda |
| Ascensione retta: | 01h38m59.13s |
| Declinazione: | +43°58'04.3" |
| Magnitudine apparente: | 9.624 |
| Moto proprio RA: | -3.5 |
| Moto proprio Dec: | -5 |
| B-T magnitude: | 12.002 |
| V-T magnitude: | 9.821 |
Cataloghi e designazioni:
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