SIMBAD references

2010AJ....140.1329G - Astron. J., 140, 1329-1336 (2010/November-0)

Photospheric variations of the supergiant γ Cyg.


Abstract (from CDS):

New high-resolution spectroscopic observations of the supergiant γ Cyg (F8 Iab) taken between 2000 and 2008 consistently show strongly reversed-C-shaped bisectors for all unblended spectral lines. Small-amplitude variations in radial velocity and line shapes occur in an irregular manner with time scales ∼100 days and longer. The radial velocities occasionally show changes as large as 2 km/s, but much smaller changes are going on continuously. Differential line bisectors show shape changes and Doppler displacement characteristic of radial expansion and contraction. These might arise from non-periodic radial pulsation-like motions or from the appearance of giant convection cells that occupy most of the visible hemisphere of the star. Line-depth ratios are correlated with the line shifts on a seasonal basis and indicate temperature changes ranging up to ∼15 K, with larger temperature occurring during times of most rapid contraction.

Abstract Copyright:

Journal keyword(s): convection - line: profiles - stars: atmospheres - techniques: radial velocities - techniques: spectroscopic

Simbad objects: 4

goto Full paper

goto View the reference in ADS

To bookmark this query, right click on this link: simbad:2010AJ....140.1329G and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact