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Astron. Astrophys. 331, 989-994 (1998)

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Hipparcos parallaxes and period-luminosity relations
of high-amplitude [FORMULA]  Scuti stars *

J.O. Petersen 1, 2 and E. Hog 1

1 Copenhagen University Observatory, NBIfAFG (oz@astro.ku.dk, erik@astro.ku.dk)
2 Theoretical Astrophysics Center, Danish National Research Foundation, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark

Received 20 October 1997 / Accepted 19 November 1997


Hipparcos parallaxes of high-amplitude [FORMULA] Scuti stars are used to derive a period-luminosity relation with a scatter of about [FORMULA] 0.1 mag, which is independent from photometric calibrations to absolute luminosities. Comparisons with several P-L relations from the literature show satisfactory agreement, and all deviations from the Hipparcos mean relation can be explained by uncertainties in the data available before Hipparcos. Hipparcos data for a few stars of relatively small and uncertain parallaxes indicate that they may have systematically very low luminosity. However, briefly discussing Lutz-Kelker corrections and considering the full sample of high-amplitude [FORMULA] Scuti stars, it is concluded that this sample is homogeneous and has similar basic physical properties as the "normal" low-amplitude [FORMULA] Scuti stars.

It is emphasized that the Hipparcos P-L relation defines a new distance scale which is independent from those of the classical Cepheids and RR Lyrae stars. Therefore, observations of high-amplitude [FORMULA] Scuti stars can be used to check fundamental distance determinations to e.g. globular clusters, the Galactic bulge and the Magellanic Clouds.

Key words: stars: ffi Scut – Cepheids – stars: distances – stars: oscillation – methods: statistical

* Based on observations made with the ESA Hipparcos satellite

Send offprint requests to: J.O. Petersen

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© European Southern Observatory (ESO) 1998

Online publication: March 3, 1998