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Pulsation Modes and Fundamental Parameters of Mira Stars

Barthes, D.

Linear pulsation models are generated using the absolute magnitudes of long period variables (LPVs) in the Large Magellanic Cloud (LMC) and in the solar neighborhood (HIPPARCOS parallaxes), as well as effective temperature estimates. The results support the hypothesis that linear modeling may be used provided that a lower mixing length (possibly e…

HIPPARCOS Astrometric Observations of Symbiotic Stars

Badiali, M.; Cardini, D.; Emanuele, A. +1 more

The Hipparcos astrometric satellite has observed a number of symbiotic stars which are also known for being mapped at radio wavelengths. The radio emission generally arises from matter ejected by the binary system, which is made visible by the ionizing radiation of the system's hot component.

Hipparcos has provided the astrometric position (w…

The Internet as a Virtual Observatory: New Elements for Ten Long Period Variables in Aquila

Mattei, J. A.; Bedient, J.; Richwine, P. +1 more

Data freely available on the Internet-CCD images from Stardial, data from the Northern Sky Variability Survey (NSVS), the Automated All-Sky Survey (ASAS), the Hipparcos Epoch Photometry Annex, and visual observations from the American Association of Variable Star Observers (AAVSO)-are combined to characterize the behavior of 10 long period variabl…

Light Elements for V353 Hydrae, a Hipparcos Eclipsing Binary

Stephan, C.; Otero, S. A.

The Hipparcos eclipsing binary V353 Hydrae has been observed visually in order to determine its period. Results of this campaign are presented. The system is an eclipsing binary in a circular orbit. The combination of visual, Hipparcos, and ASAS-3 data finally revealed that the period is 7.56 days.

New Hipparcos Variables in "The Bright Star Catalogue"

Hoffleit, Dorrit

The Hipparcos mission discovered 5665 new or previously suspected variable stars. Among these are 308 recently named variables common to "The Bright Star Catalogue". The distributions of these HR stars according to types of variation and amplitude are discussed.

Latest Surprises from Mira the Wonderful

Marengo, Massimo; Karovska, Margarita; Wood, Brian

We report the latest results from our long-term study of Mira A and its companion Mira B. These include a study of the dust environment in mid-IR wavelengths (Marengo et al. 2001), and of the accretion processes in the Mira AB interacting system (Wood, Karovska, and Raymond 2002).

RS CVN Stars in the AAVSO Photoelectric Photometry Program

Percy, John R.; Soondarsingh, Devi; Velocci, Vince

We report V Photometry of three RS CVn stars--HK Lac, SZ Psc, and Lambda And--from the AAVSO photoelectric photometry program, and from transformed Hipparcos photometry, over 3500 days. Eighteen photoelectric photometry observers contributed to this project. The stars vary on periods of days to weeks, due to rotation of a spotted photosphere. The …

Single Channel Photoelectric Photometry of RZ Arietis, 1983-2001

Thompson, Raymond R.

The AAVSO Photoelectric Photometry Archives contain 568 V observations of the SRb star RZ Ari covering 17 years. During this time, there are 22 clearly defined cycles evident in the data, ranging from 26 to 71 days and giving an average period of 51.32 days. Assuming a V magnitude of 5.87 for the comparison star, RZ Ari varied from 5.45 to 6.19, g…

Studies of Yellow Semiregular(SRd) Variables

Percy, John R.; Kolin, David L.

We have used the Hipparcos database of epoch photometry to study the variability of several yellow semiregular(SRd) variables. For some of the stars (V847 Cas, RW Cep, BM Sco, CE Vir), the results were inconclusive. For SX Lac and TY Vir, the periods found were consistent with the General Catalogue of Variable Stars (190 and 50 days respectively).…

Period Changes in Population II Cepheids: TX Del and W Vir

Percy, John R.; Hoss, Jonathan X.

We have used the Hipparcos database of epoch photometry to study the variability of two Population II Cepheids: TX Del and W Vir. We have constructed (O-c) diagrams for these stars, using the new data and data from the literature. The period of TX Del is decreasing, at a rate which is consistent with evolutionary predictions. THe periodchange of W…