Rotation of the Primary Component of Algol

Extract

1.8 A° segment of the Algol A spectrum centered at 1075.55 A° line of Ni II was scanned repeatedely with the 0.05 A° resolution from the Copernicus satellite. The numerical model is described in which 37 out of the total 55 scans obtained during two eclipses were combined in a least-squares solution, to determine the period of rotation and degree of non-solid rotation of Algol A. The period of rotation suggests full synchronism of rotational and orbital motions; the equatorial velocity is V_e = 53 ± 3 km/s. The non-solid rotation parameter ‘s’ measuring the distribution of angular velocity versus stellar latitude in ω = ω_e (1 - s + s cos² ϑ) has been found equal s = 0.07 ± 0.25 indicating the rotation law not far from solid body.