RR lyrae variables and stellar evolution in M 15
1984 ◽
Vol 105
◽
pp. 457-460
The O-C curves — widely used for investigating the period behaviour of variable stars — are generally constructed under the assumption that the period changes are linear in time. If it is indeed so, the main trend of the diagram should outline a positive or negative parabola and β values are determined to characterize the curvature of the parabolae, i.e. the rate of change of the period. This rate, however, even in the case of ω Cen does not indicate exact parabola (Belserene, 1973).
1973 ◽
Vol 21
◽
pp. 196-196
2018 ◽
Vol 14
(S344)
◽
pp. 86-89