The calcium isotopic anomaly in magnetic CP stars
نویسندگان
چکیده
منابع مشابه
The calcium isotopic anomaly in magnetic CP stars ⋆
Chemically peculiar stars in the magnetic sequence can show the same isotopic anomaly in calcium previously discovered for mercury-manganese stars in the non-magnetic sequence. In extreme cases, the dominant isotope is the exotic 48 Ca. Measurements of Ca lines arising from 3d-4p transitions reveal the anomaly by showing shifts up to 0.2 Å for the extreme cases—too large to be measurement er...
متن کاملIsotopic Anomalies in CP Stars : Helium , Mercury , Platinum , and Calcium
We review the classical observational results for isotopic abundance variations for several elements in CP stars. We concentrate on the " newest " anomaly, in calcium. The cosmically very rare isotope, 48 Ca can rival and even dominate the more common, alpha nuclide, 40 Ca. Relevant examples are found in the hot, non-magnetic HgMn stars, and the field horizontal-branch star, Feige 86. The calci...
متن کاملIsotopic anomaly and stratification of Ca in magnetic Ap stars
Aims. We have carried out an accurate investigation of the Ca isotopic composition and stratification in the atmospheres of 23 magnetic chemically peculiar (Ap) stars of different temperature and magnetic field strength. Methods. With the UVES spectrograph at the 8 m ESO VLT, we have obtained high-resolution spectra of Ap stars in the wavelength range 3000–10000 Å. Using a detailed spectrum syn...
متن کاملHeavy calcium in CP stars★
Large wavelength shifts of infrared triplet lines of Ca ii have been observed in the spectra of HgMn and magnetic Ap stars. They have been attributed to the heavy calcium isotopes, including Ca. One member of the triplet, λ8542, had been either unavailable, or of poor quality in earlier spectra. The present material shows conclusively that the stellar λ8542 shifts are consistent with an interpr...
متن کاملCa isotopic anomaly in the atmospheres of Ap stars
We present results of the Ca stratification analysis in the atmospheres of 21 magnetic chemically peculiar (Ap) stars. This analysis was based on the spectral observations carried out with the UVES spectrograph attached to the 8m VLT telescope. Ca was found to be strongly stratified in all stars with different effective temperatures and magnetic field strengths. This element is overabundant by ...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2005
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:200500013