Mapping abundance inhomogeneities and magnetic fields of chemically peculiar (CP) stars with optical aperture synthesis arrays

2003 ◽  
Author(s):  
Karine Rousselet-Perraut ◽  
Chantal Stehle ◽  
Thierry Lanz ◽  
Thomas Boudoyen ◽  
Slobodan Jankov ◽  
...  
1992 ◽  
Vol 10 (1) ◽  
pp. 71-73 ◽  
Author(s):  
R.G. Marson ◽  
T.R. Bedding ◽  
J.G. Robertson

AbstractThe technique of aperture synthesis is well developed in radio astronomy. When applied to the optical regime, aperture synthesis allows one to partially overcome the blurring effects of the atmosphere and increase the angular resolution of large telescopes to the diffraction limit. MAPPIT (Masked APerture-Plane Interference Telescope) is a multi-element interferometer which operates at the coude focus of the 3.9 m Anglo-Australian Telescope. This instrument has recently been reconfigured to operate in a dispersed mode so that simultaneous observations in a band of wavelengths are possible. We will discuss this instrument’s new mode and present observations of the double star δ Sco and an angular diameter of the previously unresolved red giant β Gru.


2009 ◽  
Vol 29 (5) ◽  
pp. 1397-1402 ◽  
Author(s):  
王海涛 Wang Haitao ◽  
朱永凯 Zhu Yongkai ◽  
蔡佳慧 Cai Jiahui ◽  
张雅静 Zhang Yajing ◽  
田贵云 Tian Guiyun

Author(s):  
J M Seach ◽  
S C Marsden ◽  
B D Carter ◽  
C Neiner ◽  
C P Folsom ◽  
...  

Abstract We present a spectropolarimetric magnetic snapshot survey of 55 stars which includes 53 F-type stars ranging from spectral types F0 to F9 plus 2 chemically peculiar stars β CrB, and δ Cap. We look for magnetic fields in stars spanning a range of effective temperatures where the transition from fossil to dynamo magnetic fields is believed to occur. High-resolution spectropolarimetry using circularly polarized spectra is used to look for a magnetic detection in the Stokes V profile, determine the mean longitudinal magnetic field (Bl), and to look for correlations with stellar parameters. Surface magnetic fields are detected on 14 F-stars, and present in every spectral class from F3V-F9V ranging in strength from 0.3 ± 0.1 G (36 UMa, F8V) to 8.3 ± 0.9 G (h Dra, F8V). Thus we find photospheric magnetic fields are present in stars as early as spectral type F3V with an outer convection zone thickness less than a few per cent of the stellar radius.


2003 ◽  
Vol 210 ◽  
pp. 209-220
Author(s):  
S. Bagnulo

Magnetic fields of chemically peculiar (CP) stars of the upper main sequence are characterised by a geometry organised at a large scale, permeating the entire photosphere, and with a typical strength of the order of 0.1–30 kG. Here I review the results obtained from statistical studies of the structures of the magnetic fields of CP stars, which are aimed at finding how magnetic strength and morphology are correlated with other stellar characteristics and with the star's evolutionary state.


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