Surprising variations in the rotation of the chemically peculiar stars CU Virginis and V 901 Orionis
Authors | |
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Year of publication | 2011 |
Type | Article in Periodical |
Magazine / Source | Astronomy and Astrophysics |
MU Faculty or unit | |
Citation | |
Web | http://www.aanda.org/index.php?option=com_article&access=doi&doi=10.1051/0004-6361/201117784&Itemid=129 |
Doi | http://dx.doi.org/10.1051/0004-6361/201117784 |
Field | Astronomy and astrophysics |
Keywords | stars: chemically peculiar – stars: variables: general – stars: individual: CU Vir – stars: individual: V901 Ori – stars: rotation |
Description | We aim to study the stability of the periods in CU Vir and V901 Ori using all accessible observational data containing phase information. We found that the shapes of their phase curves were constant, while the periods were changing. Both stars exhibit alternating intervals of rotational braking and acceleration. The rotation period of CU Vir was gradually shortening until the year 1968, when it reached its local minimum of 0.52067198 d. The period then started increasing, reaching its local maximum of 0.5207163 d in the year 2005. Since that time the rotation has begun to accelerate again. We also found much smaller period changes in CU Vir on a timescale of several years. The rotation period of V901 Ori was increasing for the past quarter-century, reaching a maximum of 1.538771 d in the year 2003, when the rotation period began to decrease. A theoretically unexpected alternating variability of rotation periods in these stars would remove the spin-down time paradox and brings a new insight into structure and evolution of magnetic upper-main-sequence stars. |
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