Doppler imaging and surface differential rotation of young open cluster stars - I. HD 307938 (R58) in IC 2602
Article
Article Title | Doppler imaging and surface differential rotation of young open cluster stars - I. HD 307938 (R58) in IC 2602 |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Marsden, S. C. (Author), Waite, I. A. (Author), Carter, B. D. (Author) and Donati, J.-F. (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 359 (2), pp. 711-724 |
Year | 2005 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1111/j.1365-2966.2005.08946.x |
Web Address (URL) | https://academic.oup.com/mnras/article/359/2/711/988520 |
Abstract | In this paper we present Doppler images of a young active G dwarf (HD 307938) in the southern open cluster IC 2602. Spectroscopic data were obtained over a four-night period in 2000 January at the 3.9-m Anglo-Australian Telescope using the University College London Echelle Spectrograph. Simultaneous photometric observations (in the V and R bands) were obtained at the 1.0-m Australian National University telescope. By applying least-squares deconvolution (LSD) to the 2500+ photospheric lines in each echelle spectrum a single high signal-to-noise ratio LSD profile was produced for each phase of the spectroscopic observations. Maximum-entropy image reconstruction, incorporating both the LSD profiles and the photometric data, was used to produce maps of the surface features of the star, with the inclusion of the photometric data producing an increase (compared with the use of spectroscopic data alone) in the spot occupancy in both low- and mid-latitude regions of the star. The maps show that HD 307938 possesses a large, broken polar spot extending down to 60 degrees latitude, as well as lower-latitude spots similar to other rapidly rotating G dwarfs. By incorporating a solar-like differential rotation law into the imaging process the surface differential rotation of HD 307938 was determined. This gave a surface shear of d omega= 0.025 plus/minus 0.015 rad d-1 (for an inclination angle of 60 degrees). Thus the equator of HD 307938 laps the poles every ~250 d and has a photospheric shear around half that of the Sun. |
Keywords | stars, stars imaging, HD 307938, late-type stars |
ANZSRC Field of Research 2020 | 519999. Other physical sciences not elsewhere classified |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2005 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | Department of Biological and Physical Sciences |
Institute for Research in Astrophysics and Planetology, France |
https://research.usq.edu.au/item/9x8yz/doppler-imaging-and-surface-differential-rotation-of-young-open-cluster-stars-i-hd-307938-r58-in-ic-2602
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