Astron. Astrophys. 361, 1005-1010 (2000)

S 10947 Aquilae RX J2009.8+1557: a probable RS CVn star which sometimes stops its eclipses ^*

G.A. Richter ¹ and J. Greiner <sup>2

1</sup> Sonneberg Observatory, 96515 Sonneberg, Germany
² Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany

Received 9 May 2000 / Accepted 14 August 2000

Abstract

We report the discovery of a new variable star, called S 10947 Aql, as the likely optical counterpart of RX J2009.8+1557. The optical variability pattern as well as the detected X-ray emission suggest that it is a chromospherically active binary of the RS Canum Venaticorum ( RS CVn) type. We discovered an occasional disappearance of the eclipsing minima as well as large variations in the eclipse amplitude. We discuss possible causes of this peculiarity.

Key words: stars: binaries: close stars: circumstellar matter stars: individual: S 10947 Aql X-rays: stars

* The complete Table 1 is available in electronic form at the CDS via anonymous ftp to ftp://cdsarc.u-strasbg.fr/pub/cats/J/A+A/361/1005 (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/361/1005

Send offprint requests to: J. Greiner (jgreiner@aip.de)

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations and discussion
• 3. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: October 10, 2000
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