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An Historical Light Curve of CF Octantis from Digitised Images of the Bamberg Plate Archive

Published online by Cambridge University Press:  05 March 2013

J. L. Innis ,
P. Heil ,
K. Thompson  and
D. W. Coates
J. L. Innis*
Affiliation:
Geophysical Institute, University of Alaska Fairbanks, Fairbanks AK 99775, USA
P. Heil
Affiliation:
IARC, University of Alaska Fairbanks, Fairbanks AK 99775, USA
K. Thompson
Affiliation:
School of Physics and Materials Engineering, Monash University, Melbourne VIC 3168, Australia
D. W. Coates
Affiliation:
School of Physics and Materials Engineering, Monash University, Melbourne VIC 3168, Australia
*
FE-mail: [email protected]
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Abstract

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Digital images were made of Bamberg Observatory Sky Patrol plates of the field surrounding the active-chromosphere star CF Octantis (HD 196818). These images, taken with an inexpensive camera, were analysed using standard aperture photometry techniques. Good agreement was found with catalogued photographic magnitudes for stars in the range mpg ∼8.5 to ∼10.5. The root-mean-square deviations in the measured differences for non-variable field stars was found to be of order 0.10 mag, although a small number of larger differences occurred. For CF Oct, a period search of data from 1966 recovered the known 20 d variation due to starspot rotational modulation, with a range of variation of order 0.5 mag photographic. For active-chromosphere stars with moderately large photometric variations (>∼0.3 mag), and moderate to long rotation periods (>∼1 week), careful analysis of similarly obtained digital copies of archive plates may provide valuable insights into historical actvity.

Keywords

stars: activitystars: individual (CF Oct)stars: spotstechniques: photometric
Type
Research Article
Information
Publications of the Astronomical Society of Australia , Volume 21 , Issue 3 , 2004 , pp. 284 - 289
Copyright
Copyright © Astronomical Society of Australia 2004

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