Extreme Ultraviolet Explorer Optical Identification Campaign.III. A Southern Hemisphere Sample of Active Late-Type Stars and White Dwarfs

Abstract

view Abstract Citations (9) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Extreme Ultraviolet Explorer Optical Identification Campaign.III. A Southern Hemisphere Sample of Active Late-Type Stars and White Dwarfs Craig, Nahide ; Christian, Damian J. ; Dupuis, Jean ; Roberts, Bryce A. Abstract We present optical identifications of 30 previously unidentified extreme ultraviolet (EUV) and soft x-ray sources coinciding with the position of faint sources detected during the all-sky surveys of the Extreme Ultraviolet Explorer ({\euve}) in the 58-174 Angstroms (0.071-0.214 keV) band and of the \rosat\ Position Sensitive Proportional Counter (PSPC) in the 5-120 Angstroms (0.1-2.4 keV x-ray) band. We present low-resolution spectra of the possible optical counterparts of the x-ray and \euve\ sources obtained with 1.5 m telescope at CTIO in 1995 May and December and 1996 February. The optical counterparts for 23 sources are identified as late-type (dKe and dMe) stars, and 4 are identified as new DA white dwarfs. All spectra of sources identified as late-type stars show the Balmer series and Ca H and K lines in emission, indicating the signature of chromospheric activity. For the white dwarfs, the joint detection by the \rosat\ PSPC and the \euve\ Lexan band indicates that they have a low-abundance of metals and that their EUV emission is mostly attenuated by the local interstellar medium (ISM). Publication: The Astronomical Journal Pub Date: July 1997 DOI: 10.1086/118469 Bibcode: 1997AJ....114..244C full text sources ADS | data products SIMBAD (78) MAST (1)