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http://hdl.handle.net/2248/5704
Title: | Magnetohydrostatic equilibrium in starspots: dependences on color (Teff) and surface gravity (g) |
Authors: | Rajaguru, S. P Hasan, S. S |
Keywords: | Sun: magnetic fields Sunspots; stars Magnetic fields Stars: spots Stars: activity |
Issue Date: | Aug-2011 |
Publisher: | Cambridge University Press |
Citation: | The Physics of Sun and Star Spots, Proceedings of the International Astronomical Union, IAU Symposium, Vol. 273, pp. 276-280 |
Series/Report no.: | International Astronomical Union Symposium; No. 273 |
Abstract: | Temperature contrasts and magnetic field strengths of sunspot umbrae broadly follow the thermal-magnetic relationship obtained from magnetohydrostatic equilibrium. Using a compilation of recent observations, especially in molecular bands, of temperature contrasts of starspots in cool stars, and a grid of Kurucz stellar model atmospheres constructed to cover layers of sub-surface convection zone, we examine how the above relationship scales with effective temperature (Teff), surface gravity g and the associated changes in opacity of stellar photospheric gas. We calculate expected field strengths in starpots and find that a given relative reduction in temperatures (or the same darkness contrasts) yield increasing field strengths against decreasing Teff due to a combination of pressure and opacity variations against Teff. |
Description: | Open Access |
URI: | http://hdl.handle.net/2248/5704 |
Appears in Collections: | IIAP Publications |
Files in This Item:
File | Description | Size | Format | |
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Magnetohydrostatic equilibrium in starspots.pdf | Open Access | 234.3 kB | Adobe PDF | ![]() View/Open |
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