Rotational Splitting and Asteroseismic Modeling of the δ Scuti Star EE Camelopardalis
Abstract
According to the rotational splitting law of g modes, the frequency spectra of EE Cam can be disentangled only with oscillation modes of ℓ = 0, 1, and 2. Fifteen sets of rotational splits were found, and they contain five sets of ℓ = 1 multiplets and 10 sets of ℓ = 2 multiplets. The rotational period of EE Cam is deduced to be {P}{rot}={1.84}-0.05+0.07 days. When we do model fittings, we use two nonradial oscillation modes (f 11 and f 32), and the fundamental radial mode f 1. The fitting results show that {χ }2 of the best-fitting model is much smaller than those of other theoretical models. The physical parameters of the best-fitting model are M = 2.04 M ⊙, Z = 0.028, T eff = 6433 K, {log}L/{L}⊙ =1.416, R = 4.12 R ⊙, {log}g=3.518, and {χ }2=0.00035. Furthermore, we find that f 11 and f 32 are mixed modes, which mainly characterize the features of the helium core. The fundamental radial mode f 1 mainly restricts the features of the stellar envelope. Finally, the acoustic radius {τ }0 and the period separation Π0 are determined to be 5.80 hr and 463.7 s, respectively, and the size of the helium core of EE Cam is estimated to be M He = 0.181 M ⊙ and R He = 0.0796 R ⊙.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2017
- DOI:
- 10.3847/1538-4357/aa6339
- arXiv:
- arXiv:1702.07428
- Bibcode:
- 2017ApJ...838...31C
- Keywords:
-
- asteroseismology;
- stars: individual: EE Cam;
- stars: rotation;
- stars: variables: delta Scuti;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 9 pages, 5 figures, 4 tables. accepted for publication in The Astrophysical Journal