NASA's Constellation-X Mission - A `Beyond Einstein' Observatory

Flare stars are a group of mostly dMe stars, which show intense flaring activity in the optical as well as in the radio and X-ray bands. These stars are characterized by the presence of chromospheric emission lines like % and Call H and K which are present even during the quiescent state. The presence of transition regions and coronae have been inferred from the detection of UV emission lines like NV, CIV, SiIV etc. with IUE and X-ray observations made with the Einstein Observatory. We report here X-ray observations of flare stars made with Einstein to measure their coronal X-ray emission during the quiescent state.

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The X-ray Structure of the Supernova Remnant G78.2+2.1

Symposium - International Astronomical Union ◽

10.1017/s0074180900034008 ◽

1983 ◽

Vol 101 ◽

pp. 281-286

Author(s):

L. A. Higgs ◽

T. L. Landecker ◽

F. D. Seward

Keyword(s):

Supernova Remnant ◽

The South ◽

X Ray ◽

South Eastern ◽

Einstein Observatory

The south-eastern portion of the supernova remnant G78.2+2.1, in Cygnus, has been detected as a weak X-ray source by the Einstein Observatory. The X-ray structure is similar to that of the radio filaments in this region, and confirms that X-ray emission in this portion of the “Cygnus super-bubble” does originate in a known supernova remnant. Marginally significant variations in X-ray hardness across the mapped area have been detected and can be related to known radio and optical features of the remnant. In its X-ray properties, G78.2+2.1 resembles IC443.

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High Resolution X-ray Spectra of Supernova Remnants

Symposium - International Astronomical Union ◽

10.1017/s0074180900033891 ◽

1983 ◽

Vol 101 ◽

pp. 205-211

Author(s):

C. R. Canizares ◽

P. F. Winkler ◽

T. H. Markert ◽

C. Berg

Keyword(s):

Supernova Remnants ◽

Abundance Ratio ◽

Ionization Equilibrium ◽

X Ray ◽

Cygnus Loop ◽

Doppler Shifts ◽

Wide Range ◽

Cas A ◽

Einstein Observatory ◽

Tycho’S Snr

We review results obtained with the Focal Plane Crystal Spectrometer (FPCS) on the Einstein Observatory. Clear evidence is found for departures from ionization equilibrium in the interior of Puppis A. This comes from the observed weakness of the forbidden lines relative to the resonance lines for the He - like triplets of O VII and Ne IX. However, it is shown that this departure from equilibrium does not alter our conclusion, based on previous FPCS results, that O and Ne are overabundant relative to Fe. The spectrum of N132D shows strong O VIII emission and very weak Fe emission, suggesting an even greater O/Fe abundance enhancement than in Puppis A. In the Cygnus Loop, the O to Ne abundance ratio is approximately solar; we have no information about Fe. The O VII triplet shows clear evidence for departures from ionization equilibrium in the Cygnus Loop. The spectrum of Tycho's SNR contains lines from ionization stages of Fe XVII through Fe XXIII and XXIV, indicating that a wide range of ionization conditions are present. Cas A and Kepler's SNR show relatively less emission from the higher ionization stages. For Tycho, we measured the strength of the strong Si XIII lines, and we find that a many-fold overabundance of Si relative to Fe is required regardless of the equilibrium state of the emitting plasma (confirming the Solid State Spectrometer results). On a separate topic, the completed analysis of X-ray Doppler shifts in Cas A suggests that the emitting material is concentrated in a ring that is inclined to the line of sight and is expanding at ~5000 km s−1.

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RS CVn Systems: The High Energy Picture

International Astronomical Union Colloquium ◽

10.1017/s0252921100096421 ◽

1983 ◽

Vol 71 ◽

pp. 415-427 ◽

Cited By ~ 2

Author(s):

P.A. Charles

Keyword(s):

Line Emission ◽

High Energy ◽

Close Binaries ◽

Stellar Rotation ◽

Active Systems ◽

X Ray ◽

Coronal Activity ◽

Solar Abundances ◽

Scaled Models ◽

Einstein Observatory

AbstractThe discovery of X-ray emission from RS CVn systems by HEAO-1 and subsequent surveys by the Einstein Observatory have shown that these close binaries exhibit greatly enhanced coronal activity. Here we review the 3 main observational areas: (1) results of the X-ray surveys of RS CVn systems and other late-type stars which indicate how the X-ray luminosity is correlated with the binary period (and hence stellar rotation) and other coronal activity indicators. This will be discussed in the context of scaled models of the solar corona; (2) X-ray spectroscopy of the most active systems which show multitemperature spectra and line emission consistent with solar abundances of the heavy elements; (3) observations of X-ray “flare-type” activity that has been associated with several RS CVn systems.

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X-Ray Sources of Cosmological Relevance

Symposium - International Astronomical Union ◽

10.1017/s007418090003850x ◽

1983 ◽

Vol 104 ◽

pp. 7-18

Author(s):

T. Maccacaro ◽

I. M. Gioia

Keyword(s):

Proportional Counter ◽

Extragalactic Astronomy ◽

X Ray ◽

Einstein Observatory

The imaging and spectroscopic instruments onboard the Einstein Observatory (Giacconi et al. 1979) have been extensively used to study in detail the X-ray properties of a large variety of astronomical objects. In this paper we will briefly discuss some of the most relevant results on extragalactic astronomy obtained mainly with the Imaging Proportional Counter (IPC).

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X Sources in δ Scuti Stars: an Ultraviolet Study of 71 Tau

International Astronomical Union Colloquium ◽

10.1017/s0252921100118032 ◽

1993 ◽

Vol 139 ◽

pp. 396-396

Author(s):

L.E. Pasinetti Fracassini ◽

L. Pastori ◽

F. De Nile ◽

E. Poretti ◽

E. Antonello

Keyword(s):

Mass Loss ◽

Spectroscopic Data ◽

Pulsation Period ◽

X Ray ◽

Chromospheric Activity ◽

Hyades Cluster ◽

Photometric Observations ◽

Scuti Stars ◽

Einstein Observatory ◽

Δ Scuti Stars

IUE observations of δ Scuti variables were planned to study the correlations between chromospheric activity and dynamics of pulsations, convection, rotation and to search for evidence of mass loss. So far we observed the following stars: ρ Pup, β Cas, o1 Eri, K2 Boo, τ Peg, 69 Tau, 71 Tau and τ Cyg. Results and discussions on our survey may be found in Pasinetti Fracassini et al. (1990) and Fracassini et al. (1991).Ultraviolet spectroscopic data (6 LWP and 3 SWP spectra) of 71 Tau were obtained with IUE in the year 1990, spanning an interval of 5h35rn and covering about 1.5 cycles of the pulsation period. The period, derived from new photometric observations, is 4h32m with an cimplitude of 0m.028. This variable is the most intense X-ray source in the Hyades cluster according to the results of Einstein Observatory.

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