Letter to the Editor

Probable nonradial g-mode pulsation in early A-type stars

¹ INAF-Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, Italy e-mail: [elio;luciano;rainer]@merate.mi.astro.it
² Institut d'Astrophysique et de Géophysique de l'Université de Liège, 17 allée du 6 Août, 4000 Liège, Belgium e-mail: miglio@astro.ulg.ac.be

Received: 12 October 2005
Accepted: 13 November 2005

Abstract

Context.

Aims.Asteroseismology of early A-type stars could be a new tool to test stellar convection theories.

Methods.A survey for line profile variability in early A-type stars has been performed in order to detect nonradial pulsation signatures.

Results.The star HR 6139, with spectral type A2V and estimated  K, shows evident line profile variations that can be explained by oscillations in prograde g-modes. This feature and the known photometric variability are similar to those observed in the Slowly Pulsating B-type stars. However HR 6139 is much cooler than the cool border of the instability strip of such variables, and it is hotter than the blue edge of the δ Scuti instability strip. There are indications of a tiny variability also in other four objects, whose nature is not yet clear.

Conclusions.