THE DISCOVERY OF DIFFERENTIAL RADIAL ROTATION IN THE PULSATING SUBDWARF B STAR KIC 3527751
- Department of Physics, Astronomy, and Materials Science, Missouri State University, Springfield, MO 65897 (United States)
- Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breña Baja (Spain)
- Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium)
- Uniwersytet Pedagogiczny, Obserwatorium na Suhorze, ul. Podchorażych 2, 30-084 Kraków (Poland)
We analyze 3 yr of nearly continuous Kepler spacecraft short cadence observations of the pulsating subdwarf B (sdB) star KIC 3527751. We detect a total of 251 periodicities, most in the g-mode domain, but some where p-modes occur, confirming that KIC 3527751 is a hybrid pulsator. We apply seismic tools to the periodicities to characterize the properties of KIC 3527751. Techniques to identify modes include asymptotic period spacing relationships, frequency multiplets, and the separation of multiplet splittings. These techniques allow for 189 (75%) of the 251 periods to be associated with pulsation modes. Included in these are three sets of ℓ = 4 multiplets and possibly an ℓ = 9 multiplet. Period spacing sequences indicate ℓ = 1 and 2 overtone spacings of 266.4 ± 0.2 and 153.2 ± 0.2 s, respectively. We also calculate reduced periods, from which we find evidence of trapped pulsations. Such mode trappings can be used to constrain the core/atmosphere transition layers. Interestingly, frequency multiplets in the g-mode region, which sample deep into the star, indicate a rotation period of 42.6 ± 3.4 days while p-mode multiplets, which sample the outer envelope, indicate a rotation period of 15.3 ± 0.7 days. We interpret this as differential rotation in the radial direction with the core rotating more slowly. This is the first example of differential rotation for a sdB star.
- OSTI ID:
- 22522392
- Journal Information:
- Astrophysical Journal, Vol. 805, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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