Discovery of 17 new sharp - lined Ap stars with magnetically resolved lines ⋆
نویسندگان
چکیده
Chemically peculiar A stars (Ap) are extreme examples of the interaction of atomic element diffusion processes with magnetic fields in stellar atmospheres. The rapidly oscillating Ap stars provide a means for studying these processes in 3D and are at the same time important for studying the pulsation excitation mechanism in A stars. As part of the first comprehensive, uniform, high resolution spectroscopic survey of Ap stars, which we are conducting in the southern hemisphere with the Michigan Spectral Catalogues as the basis of target selection, we report here the discovery of 17 new magnetic Ap stars having spectroscopically resolved Zeeman components from which we derive magnetic field moduli in the range 3 − 30 kG. Among these are 1) the current second-strongest known magnetic A star, 2) a double-lined Ap binary with a magnetic component and 3) an A star with particularly peculiar and variable abundances. Polarimetry of these stars is needed to constrain their field geometries and to determine their rotation periods. We have also obtained an additional measurement of the magnetic field of the Ap star HD92499.
منابع مشابه
Two new chemically peculiar stars with resolved magnetically split lines ⋆
We report the discovery of resolved magnetically split lines in two chemically peculiar stars, the SrEuCr star HD 92499 and the Bp SiCr star HD 157751. From FEROS spectra, we have measured a mean magnetic field modulus of 8.5 kG for HD 92499 and a mean magnetic field modulus of 6.6 kG for HD 157751. Both stars have small projected rotational velocities: v sin i = 3.0 km s −1 and 8.5 km s −1 , r...
متن کاملA search for radial magnetic field gradients in Ap atmospheres
For the first time the possible presence of radial gradients of magnetic fields in the atmospheres of three magnetic Ap stars has been critically examined by measurements of the mean magnetic field modulus from spectral lines resolved into magnetically split components lying on the different sides of the Balmer jump. A number of useful diagnostic lines below and above the Balmer discontinuity, ...
متن کاملSearch for magnetic fields in HgMn stars by using relative strengths of multiplet 74 Fe II lines ?
The anomalous strength of the Fe II λ 6147.7 line relative to Fe II λ 6149.2 in the stars with magnetic fields is used for detecting magnetic fields in very slowly rotating HgMn stars. The diagnosis based on this pair of magnetically sensitive Fe lines is a simple and fast tool, but its application to more rapidly rotating HgMn stars is hampered by blending with Hg II λ 6149.5. For spectra of s...
متن کاملTesting the companion hypothesis for the origin of the X-ray emission from intermediate-mass main-sequence stars
Context. The X-ray emission from B-type main-sequence stars is a longstanding mystery in stellar coronal research. Since there is no theory at hand that explains intrinsic X-ray emission from intermediate-mass main-sequence stars, the observations have often been interpreted in terms of (unknown) late-type magnetically active companion stars. Aims. Resolving the hypothesized companions requires...
متن کاملThe Ap spectroscopic binary HD 59435 revisited ? , ? ?
HD 59435 is a double-lined spectroscopic binary, one component of which is a magnetic Ap star and the other a G8 or K0 giant (Wade et al. 1996). Both components are very slowly rotating, and the Ap star exhibits spectral lines resolved into their magneti cally-split components. Herein we report additional measurements of the mean magnetic field modulus of the Ap star, measurements of the radial...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2008