A scenario of planet erosion by coronal radiation
(Submitted on 9 Feb 2010 (v1), last revised 10 Aug 2010 (this version, v2))Context: According to theory, high-energy emission from the coronae of cool stars can severely erode the atmospheres of orbiting planets. No observational tests of the long term effects of erosion have yet been made. Aims: To analyze the current distribution of planetary mass with X-ray irradiation of the atmospheres in order to make an observational assessment of the effects of erosion by coronal radiation. Methods: We study a large sample of planet-hosting stars with XMM-Newton, Chandra and ROSAT; make a careful identification of X-ray counterparts; and fit their spectra to make accurately measurements of the stellar X-ray flux. Results: The distribution of the planetary masses with X-ray flux suggests that erosion has taken place: most surviving massive planets, (M_p sin i >1.5 M_J), have been exposed to lower accumulated irradiation. Heavy erosion during the initial stages of stellar evolution is followed by a phase of much weaker erosion. A line dividing these two phases could be present, showing a strong dependence on planet mass. Although a larger sample will be required to establish a well-defined erosion line, the distribution found is very suggestive. Conclusions: The distribution of planetary mass with X-ray flux is consistent with a scenario in which planet atmospheres have suffered the effects of erosion by coronal X-ray and EUV emission. The erosion line is an observational constraint to models of atmospheric erosion.Submission history
From: Jorge Sanz-Forcada [view email] [v1] Tue, 9 Feb 2010 15:11:52 GMT (47kb) [v2] Tue, 10 Aug 2010 13:58:44 GMT (47kb)........"
URL: http://arxiv.org/abs/1002.1875
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Abstract
Context. According to theory, high-energy emission from the coronae of cool stars can severely erode the atmospheres of orbiting planets. No observational tests of the long-term erosion effects have been made yet.
Aims. We analyze the current distribution of planetary mass with X-ray irradiation of the atmospheres to make an observational assessment of the consequences of erosion by coronal radiation.
Methods. We studied a large sample of planet-hosting stars with XMM-Newton, Chandra, and ROSAT, carefully identified the X-ray counterparts, and fit their spectra to accurately measure the stellar X-ray flux.
Results. The distribution of the planetary masses with X-ray flux suggests that erosion has taken place. Most surviving massive planets (Mp sin i > 1.5 MJ) have been exposed to lower accumulated irradiation. Heavy erosion during the initial stages of stellar evolution is followed by a phase of much weaker erosion. A line dividing these two phases could be present, showing a strong dependence on planet mass. Although a larger sample will be required to establish a well-defined erosion line, the distribution found is very suggestive.
Conclusions. The distribution of planetary mass with X-ray flux is consistent with a scenario in which planet atmospheres have suffered the effects of erosion by coronal X-ray and EUV emission. The erosion line is an observational constraint for models of atmospheric erosion.
http://www.aanda.org/articles/aa/pdf/2010/03/aa13670-09.pdf
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Abstract
Evidence from Apollo 11 and Apollo 12 lunar samples indicates that particle radiation is not important for the production of grains in the lunar soil greater than 22 microns in size even though sufficiently prolonged irradiations by protons, heavy ions and electrons fracture minerals and glasses like those found on the lunar surface.
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Copyright © 1971 Published by Elsevier B.V......." [ http://www.sciencedirect.com/science/article/pii/0012821X71900161 ]
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Wednesday, December 11, 2013
Moon Dust - I
http://control-avles-blogs.blogspot.it/2013/12/moon-dust-i.html
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