Activity in X-ray-selected late-type stars

Journal Article · Tue Mar 01 04:00:00 EST 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166137· OSTI ID:7251952

Takalo, L O; Nousek, J A

A spectroscopic study has been conducted of nine X-ray bright late-type stars selected from two Einstein X-ray surveys: the Columbia Astrophysical Laboratory Survey (five stars) and the CFA Medium Sensitivity Survey (MSS; four stars). Spectral classes were determined and radial and V sin(i) velocities were measured for the stars. Four of the Columbia Survey stars were found to be new RS CVn-type binaries. The fifth Columbia survey star was found to be an active G dwarf star without evidence for binarity. None of the four MSS stars were found to be either binaries or optically active stars. Activity in these stars was assessed by measuring the excess emission in H-alpha and the Ca II IRT (8498, 8542) lines in comparison with inactive stars of similar spectral types. A correlation was found between X-ray luminosity and V sin(i) and H-alpha line excess. The measured excess line emission in H-alpha was also correlated with V sin(i) but not with the IRT line excess. 36 references.

• Research Organization: Pennsylvania State Univ., University Park (USA)
• OSTI ID: 7251952
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 326; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BALMER LINES
BINARY STARS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DWARF STARS
EMISSION SPECTRA
LUMINOSITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIAL VELOCITY
SPECTRA
STARS
STELLAR ACTIVITY
VELOCITY