AAS Meeting #193 - Austin, Texas, January 1999
Session 102. Binary Stars
Display, Saturday, January 9, 1999, 9:20am-4:00pm, Exhibit Hall 1

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[102.15] BeppoSAX Observations of AR Lacertae

I. Pagano (JILA, U. Colorado \& Catania Astrophys. Obs., Italy), M. Rodon\`o (Catania U. \& Catania Astrophys. Obs., Italy), F. M. Walter (New York State U., Stony Brook), G. Leto (CASA, U. Colorado \& Inst. of Radioastromony of CNR, Italy), S. Catalano (Catania Astrophys. Obs., Italy)

We present the results of an X-ray observation of the binary system AR Lacertae (HD 210334) obtained with the Low and Medium Energy Concentrator Spectrometers (LECS & MECS) and with the Phoswich Detector System (PDS) on board the Beppo-SAX satellite.

Two flare episodes were detected, one in each of the two run in which the observations were splitted, with comparable peak luminosity. Furthermore, low amplitude flares appears to be the main cause of light curve variation. A very tight and shallow primary eclipse was observed, different from primary eclipses observed at other epochs by other X-ray telescopes. No sign of secondary eclipse can be inferred from these data.

The PDS data show that the emission in the 15-300 keV range is generally not detectable, but there is enough evidence of hard photons during the onset of a flare on Nov~4 and during the flare on Nov~11, whilst no significative emission in the 15-300 keV range was detected during the major flare on Nov~4.

The AR Lac spectrum between 0.1 and 9 keV is well fitted by a two component optical-thin plasma model based on the MEKAL plasma emission code with subsolar global metal abundance. We performed also the spectral analysis of the two separate segments of data, finding that the plasma temperatures, abundances and emission measures did not significantly change between the two time intervals.

The author(s) of this abstract have provided an email address for comments about the abstract: ipagano@casa.colorado.edu

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