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 Teff = 8800 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. © ESO 2005.
Antonello E., Mantegazza L., Rainer M., Miglio A. (2006). Probable nonradial g-mode pulsation in early A-type stars. ASTRONOMY & ASTROPHYSICS, 445(1), 15-18 [10.1051/0004-6361:200500216].
Probable nonradial g-mode pulsation in early A-type stars
Miglio A.
2006
Abstract
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 Teff = 8800 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. © ESO 2005.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
