Gamma Doradus variable
Gamma Doradus star or Gamma Doradus variables are variable stars, which vary by non-radial pulsations on the surface in their luminosity. Such stars are typically young, lie on the main sequence and have a spectral type between F0 and F2. Characteristic amplitudes of the brightness variations are up to 0.1 mag with periods from 0.4 to 3 days.
The prototype gamma Doradus was identified in 1963 as a variable star and was long considered variables for no reason. The assumption of non-radial oscillations as the cause of light variation depends on the exclusion of all other known mechanisms.
The absolute magnitudes of gamma Doradus stars lie between 3.1 and 1.9 like what the 5 - equivalent to 15 times the solar luminosity. The effective temperature is in the range 6950-7350 K, the radius of 1.43 to 2.36 solar radii and the mass of 1.51 to 1.84 solar masses. The observed radial velocities are low and are between 1 and 4 km / s
All Gamma Doradus variables are at or slightly above the main sequence just outside or at the blue edge of the instability strip. With the narrow band of parameters they are considered the most homogeneous group among the variable stars. In its position in the Hertzsprung -Russell diagram, the Gamma Doradus variables and the delta Scuti star partially overlap. Some stars could be classified both as a Delta Scuti star as well as a gamma Doradus star, as they characteristic of gamma Doradus stars in the order of days show periods and short- period safe oscillations with periods ranging from minutes to hours, typical are for Delta Scuti stars.
The group discovered the Gamma Doradus variables is relatively small, and all known members belong to the young disk population. After a theoretical study may be at Gamma Doradus stars either main -sequence stars or just born stars that cross the Gamma Doradus instability strip. These two types differ in their mass and the depth of the outer convective layer. These differences should be reflected in the frequency spectrum, so that an age determination using the asteroseismology is possible.