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Absolute Measurements of Starspot Area and Temperature

Published online by Cambridge University Press:  12 April 2016

James E. Neff ,
Douglas O’Neal  and
Steven H. Saar
James E. Neff
Affiliation:
Astronomy & Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16801
Douglas O’Neal
Affiliation:
Astronomy & Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16801
Steven H. Saar
Affiliation:
Harvard/Smithsonian Center for Astrophysics, Mail Stop 58, 60 Garden Street, Cambridge, MA 02138

Extract

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Photometric and spectroscopic variability of late-type stars frequently has been interpreted as evidence of magnetic activity. The standard picture of stellar activity – inherited from solar observations – includes cool, dark “spots” in the photosphere and hot, dense regions in the chromosphere and coronae. The immediate cause of each of these phenomena is a closed topology of the local magnetic field. Because stars appear as mere points of light, these localized phenomena have not been directly resolvable on stars other than the Sun. Most observed effects are produced by an asymmetric distribution of starspots. If the distribution is symmetric, it would escape detection by most current techniques of light-curve and line-profile modeling. Even more troubling, the stellar properties measured with these techniques describe only a difference between contrasting hemispheres, not an absolute measure.

Type
II. Atmospheres, a window to the interior
Information
International Astronomical Union Colloquium , Volume 137: Inside the Stars , 1993 , pp. 193 - 195
Copyright
Copyright © Astronomical Society of the Pacific 1993

References

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