X‐Ray Spectroscopy of Rapidly Rotating, Late‐Type Dwarf Stars

1999 ◽  
Vol 512 (2) ◽  
pp. 874-891 ◽  
Author(s):  
K. P. Singh ◽  
S. A. Drake ◽  
E. V. Gotthelf ◽  
N. E. White
Keyword(s):  
Late Type ◽  
Dwarf Stars ◽  
X Ray

scholarly journals On the Stellar Rotation-Activity Connection

1983 ◽  
Vol 102 ◽  
pp. 279-300 ◽  
Author(s):  
Robert Rosner
Keyword(s):  
Surface Activity ◽  
Rotation Rate ◽  
Late Type ◽  
Stellar Rotation ◽  
Dwarf Stars ◽  
X Ray

I discuss the connection between the rotation rate of late-type dwarf stars and their level of surface “activity” (as deduced from visible, UV, and X-ray observations) from both theoretical and observational perspectives.

Contributions of late-type dwarf stars to the soft X-ray diffuse background

1990 ◽  
Vol 361 ◽  
pp. 207 ◽  
Author(s):  
J. H. M. M. Schmitt ◽  
S. L. Snowden
Keyword(s):  
Late Type ◽  
Dwarf Stars ◽  
X Ray ◽  
Diffuse Background

scholarly journals X-Ray Coronae from Single Late-Type Dwarf Stars

1998 ◽  
Vol 188 ◽  
pp. 222-223
Author(s):  
K.P. Singh ◽  
S.A. Drake ◽  
N.E. White
Keyword(s):  
Binary Systems ◽  
Late Type ◽  
Dwarf Stars ◽  
X Ray ◽  
Elemental Abundances ◽  
Moderate Resolution

Study of X-ray coronae from late-type stars with moderate resolution X-ray spectroscopy with ASCA, has led to the characterization of temperatures and measurements of elemental abundances in their coronae. Several RS CVn and Algol-type binary systems, and single late-type stars have been observed. We present here the results obtained from X-ray spectroscopy of recently observed single F-G-K-M type dwarfs. The sample observed with ASCA contains αCen (Mewe et al. 1997), π1UMa (Drake et al. 1994), YY Gem, Speedy Mic, GJ 890 (Singh et al. 1997), EK Dra, HN Peg, κ1Cet (Guedel et al. 1997), AB Dor (Mewe et al. 1996) and HD 35850 (Tagliaferri et al. 1997).

X-Ray Coronae from Single Late-Type Dwarf Stars

1998 ◽  
pp. 222-223
Author(s):  
K. P. Singh ◽  
S. A. Drake ◽  
N. E. White
Keyword(s):  
Late Type ◽  
Dwarf Stars ◽  
X Ray

scholarly journals X-Ray Emission from Distant Stellar Clusters

1998 ◽  
Vol 188 ◽  
pp. 220-221
Author(s):  
N.S. Schulz ◽  
J.H. Kastner
Keyword(s):  
Main Sequence ◽  
Sequence Evolution ◽  
Late Type ◽  
Low Mass Stars ◽  
Dwarf Stars ◽  
X Ray ◽  
T Tauri ◽  
Low Mass ◽  
M Stars ◽  
M Dwarf Stars

Observations with the Einstein Observatory indicated that stellar X-ray activity diminishes in clusters older than 70 Myr (Pleiades). ROSAT observations of older clusters also support this result (see Caillault 1995 and references therein). The timescales over which young stars diminish in X-ray luminosity depends on spectral type (Randich et al. 1996), leading to the conclusion that X-ray activity in late type PMS depends on age and stellar mass. F and G-stars approach the main sequence much faster and the diminishing rates of X-ray activity from F to M stars start to differ considerably. Kastner et al. (1997) observed that the mean of the ratio Lx/Lbol for K and M dwarf stars increases monotonically for low-mass stars from the very early T Tauri stage through the age of the Pleiades cluster, reflecting the contraction and spin-up of such stars during pre-main sequence evolution. This ratio then decreases towards middle aged stars, as late-type main sequence stars spin down. Here we extend this result by including more distant clusters that are younger overall than those considered by Kastner et al. and also including earlier spectral types.

scholarly journals Mapping Cool Gas in the ISM with ROSAT

1997 ◽  
Vol 166 ◽  
pp. 283-286
Author(s):  
I.B. Hutchinson ◽  
R.S. Warwick ◽  
R. Willingale
Keyword(s):  
Column Density ◽  
Line Of Sight ◽  
Local Interstellar Medium ◽  
Late Type ◽  
Dwarf Stars ◽  
General Direction ◽  
X Ray ◽  
White Dwarf Stars ◽  
Cool Gas ◽  
Using Data

AbstractWe have investigated the distribution of cool gas within the local interstellar medium (<150 pc) using data derived from both the ROSAT X-ray and EUV all-sky surveys. The EUV/X-ray spectra for a sample of 89 white dwarf stars and 200 active late-type stars have been analysed to give an estimate of the gas column density along each object’s line of sight. In order to extend the sky coverage we have also included in the analysis 190 late-type stars detected only in the X-ray band. The derived NHI measurements confirm the size of the local low density bubble as typically 50-100 pc and also show that in the general direction of Loop I there is a substantial excess of absorption at a range of distances from 10-150 pc.

scholarly journals Spectroscopy of Stellar X-ray Sources in the Magellanic Clouds

1984 ◽  
Vol 108 ◽  
pp. 305-312
Author(s):  
J. B. Hutchings
Keyword(s):  
Black Hole ◽  
Magellanic Cloud ◽  
Active Galaxies ◽  
Magellanic Clouds ◽  
Dwarf Stars ◽  
X Ray ◽  
Preliminary Comparison ◽  
The Galaxy ◽  
Optical Identifications ◽  
X Ray Binaries

In the Magellanic Clouds, about 75 candidate stellar X-ray sources have been detected. Most of these positions have now been investigated and optical identifications made for ~ 50%. The majority of sources are foreground dwarf stars or background active galaxies. Detailed investigations exist for 3 SMC sources and 6 LMC sources. It is possible to make a preliminary comparison with the population of galactic X-ray sources. The Magellanic Cloud X-ray binaries have a number of unique or remarkable properties and the most important ones are presented and discussed. These include the most rapid pulsars (SMC X-1, 0538–66), the possible precessing disk in LMC X-4, and the black hole candidates LMC X-3, LMC X-1. The properties of these objects relate to the evolution of stars in the Magellanic Clouds and how it differs from the Galaxy.

scholarly journals X–Ray Activity and Rotation on Bright Late–Type Giants and Supergiants

2004 ◽  
Vol 215 ◽  
pp. 292-293
Author(s):  
Stefano Covino ◽  
Gianpiero Tagliaferri ◽  
José Renan de Medeiros
Keyword(s):  
Statistical Relation ◽  
Late Type ◽  
X Ray

We present and discuss statistical relation between rotation and X-ray activity for giant and supergiant stars.”

Optical Identification of the ROSAT All-Sky Survey Sources in Two 2° × 2° Fields

1997 ◽  
Vol 159 ◽  
pp. 427-428
Author(s):  
Y. Zhao ◽  
J. Zhong ◽  
J. Wei ◽  
J. Hu ◽  
Q. Li
Keyword(s):  
Ccd Camera ◽  
Seyfert Galaxies ◽  
Astronomical Observatory ◽  
Active Galaxies ◽  
Clusters Of Galaxies ◽  
Late Type ◽  
Optical Identification ◽  
X Ray ◽  
Sky Survey

AbstractWe used the CCD camera and spectrograph of the 2.16-m telescope of Beijing Astronomical Observatory to identify the ROSAT All-Sky survey sources in two 2° Ü 2° fields. Of a total of 16 X-ray sources, we identified 13 of them as follows: two QSOs, two Seyfert galaxies, two active galaxies, two clusters of galaxies, and five late-type stars. Three X-ray sources remained unidentified.

Sign in / Sign up

Export Citation Format

Share Document