Radial velocities of very low mass stars and candidate brown dwarf members of the Hyades and Pleiades

Abstract

view Abstract Citations (54) References (63) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radial Velocities of Very Low mass Stars and Candidate Brown Dwarf Members of the Hyades and Pleiades Stauffer, John R. ; Liebert, James ; Giampapa, Mark ; Macintosh, Bruce ; Reid, Neill ; Hamilton, Donald Abstract We have determined H alpha equivalent widths and radial velocities with 1 sigma accuracies of approximately 5 km s-1 for approximately 20 candidate very low mass members of the Hyades and Pleiades clusters. The radial velocities for the Hyades sample suggest that nearly all of these stars are indeed highly probable members of the Hyades. The faintest stars in the Hyades sample have masses of order 0.1 solar mass. We also obtained radial velocities for four candidate very low mass members of the Pleiades and two objects that are candidate BD Pleiads. All of these stars have apparent V magnitudes fainter than the Hyades stars we observed, and the resultant radial velocity accuracy is worse. We believe that the three brighter stars are indeed likely very low mass stellar members of the Pleiades, whereas the status of the two brown dwarf candidates is uncertain. The Hyades stars we have observed and the three Pleiades very low mass stars are the lowest mass members of any open cluster whose membership has been confirmed by radial velocities and whose chromospheric activity has been measured. We see no change in chromospheric activity at the boundary where stars are expected to become fully convective (M approximately equals 0.3 solar mass) in either cluster. In the Pleiades, however, there may be a decrease in chromospheric activity for stars with (V-I)K greater than 3.5 (M less than or equal to 0.1 solar mass). Publication: The Astronomical Journal Pub Date: July 1994 DOI: 10.1086/117054 Bibcode: 1994AJ....108..160S Keywords: Astronomical Spectroscopy; Dwarf Stars; Radial Velocity; Star Clusters; Stellar Spectra; Charge Coupled Devices; Pleiades Cluster; Stellar Mass; Astrophysics; OPEN CLUSTERS AND ASSOCIATIONS: INDIVIDUAL: HYADES; OPEN CLUSTERS AND ASSOCIATIONS: INDIVIDUAL: PLEIADES; STARS: BROWN DWARFS full text sources ADS | data products SIMBAD (33)