Doppler imaging and surface differential rotation of young open cluster stars - I. HD 307938 (R58) in IC 2602

Marsden, S. C. and Waite, I. A. and Carter, B. D. and Donati, J.-F. (2005) Doppler imaging and surface differential rotation of young open cluster stars - I. HD 307938 (R58) in IC 2602. Monthly Notices of the Royal Astronomical Society, 359 (2). pp. 711-724. ISSN 0035-8711

[img]
Preview
PDF
Marsden_et_al_j.1365-2966.2005.08946.x.pdf

Download (848Kb)

Abstract

[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.


Statistics for USQ ePrint 455
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Reproduced in accordance with the copyright policy of the publisher.
Depositing User: epEditor USQ
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 00:21
Last Modified: 02 Jul 2013 22:32
Uncontrolled Keywords: stars, stars imaging, HD 307938, late-type stars
Fields of Research (FOR2008): 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020102 Astronomical and Space Instrumentation
Identification Number or DOI: doi: 10.1111/j.1365-2966.2005.08946.x
URI: http://eprints.usq.edu.au/id/eprint/455

Actions (login required)

View Item Archive Repository Staff Only