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The Faint Young Sun Paradox: An Observational Test of an Alternative Solar Model

Gaidos, Eric J. and Güdel, Manuel and Blake, Geoffrey A. (2000) The Faint Young Sun Paradox: An Observational Test of an Alternative Solar Model. Geophysical Research Letters, 27 (4). pp. 501-503. ISSN 0094-8276. doi:10.1029/1999GL010740.

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We report the results of deep observations at radio (3.6 cm) wavelengths of the nearby solar‐type star π^01 Ursa Majoris with the Very Large Array (VLA) intended to test an alternative theory of solar luminosity evolution. The standard model predicts a solar luminosity only 75% of the present value and surface temperatures below freezing on Earth and Mars at 4 Ga, seemingly in conflict with geologic evidence for liquid water on these planets. An alternative model invokes a compensatory mass loss through a declining solar wind that results in a more consistent early luminosity. The free‐free emission from an enhanced wind around nearby young Sun‐like stars should be detectable at microwave frequencies. Our observations of π^01 UMa, a 300 million year‐old solar‐mass star, place an upper limit on the mass loss rate of 4–5 × 10^(−11) M_⊙ yr^(−1). Total mass loss from such a star over 4 Gyr would be less than 6%. If this star is indeed an analog of the early Sun, it casts doubt on the alternative model as a solution to the faint young Sun paradox, particularly for Mars.

Item Type:Article
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URLURL TypeDescription DOIArticle
Gaidos, Eric J.0000-0002-5258-6846
Blake, Geoffrey A.0000-0003-0787-1610
Additional Information:© 2000 American Geophysical Union. Received 24 September 1999; accepted 27 October 1999. E.J.G. is supported by the NASA Astrobiology program. G.A.B. acknowledges support from the NASA Exobiology program. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The SIMBAD database is maintained by the Centre Données astronomiques de Strasbourg, France.
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Issue or Number:4
Record Number:CaltechAUTHORS:20120914-103011820
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Official Citation:Gaidos, E. J., M. Güdel, and G. A. Blake (2000), The Faint Young Sun Paradox: An observational test of an alternative solar model, Geophys. Res. Lett., 27(4), 501–503, doi:10.1029/1999GL010740.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34090
Deposited On:14 Sep 2012 19:11
Last Modified:09 Nov 2021 23:06

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