ISSN:
1572-946X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The results of Herbig Be-star periodicity search are discussed. The cyclic phenomena can be roughly divided into the following three types: P0 - long-term periodic variability with periods of more than one year and amplitudes of 0 . m 4-4 . m 0V. The following stars show this type of variability (PO in years are presented in parenthesis): VX Cas (4.46), UX Ori (3.70), BF Ori (6.3), VV Ser (2.87), V517 Cyg (8.9-9.6), V373 Cep (7.7), and the others. P1 - middle-scale quasi-cyclic variability with periods of 10-100 days and amplitudes of 0 . m 05-0 . m 5V. Twenty-three stars show this type of cyclicity. 7 stars are suspected to have this type of variability. P2 - short-periodic and quasi-cyclic variability with amplitudes of 0 . m 05-0 . m 5V and periods of less than 10 days. In some cases the periodicity correlates with variations in strong emission line profiles. As an example, the properties of AB Aur are discussed. A total of 14 objects are suspected to have short-periodic quasi-cyclicity. Four of them show a high probability of periods (0.85 〈 II 〈 0.99). The discovered cyclic phenomena are interpreted in terms of Keplerian rotation of various structures in accretion disks and formations. The hypothesis of giant protocomets is suggested to explain the periods P0. Short-period cyclicity is associated with the changing of hot compact shell shapes modulated by rotation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00626923
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