Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres. I. High-Energy Irradiances (1-1700 Å)

By I. Ribas, E. Guinan, M. Gudel, M. Audard. 2004

740 citations recorded by the source corpus.

We report on the results of the Sun in Time multiwavelength program (X-rays to UV) of solar analogs with ages covering ~0.1-7 Gyr. The chief science goals are to study the solar magnetic dynamo and to determine the radiative and magnetic properties of the Sun during its evolution across the main sequence. The present paper focuses on the latter goal, which has the ultimate purpose of providing the spectral irradiance evolution of solar-type stars to be used in the study and modeling of planetary atmospheres. The results from the Sun in Time program suggest that the coronal X-ray-EUV emissions of the young main-sequence Sun were ~100-1000 times stronger than those of the present Sun. Similarly, the transition region and chromospheric FUV-UV emissions of the young Sun are expected to be 20-60 and 10-20 times stronger, respectively, than at present. When we consider the integrated high-energy emission from 1 to 1200 Å, the resulting relationship indicates that about 2.5 Gyr ago the solar high-energy flux was about 2.5 times the present value and about 3.5 Gyr ago was about 6 times the present value (when life supposedly arose on Earth). The strong radiation emissions inferred should have had major influences on the thermal structure, photochemistry, and photoionization of planetary atmospheres and have played an important role in the development of primitive life in the solar system. Some examples of the application of the Sun in Time results on exoplanets and on early solar system planets are discussed.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/04bf65e27d727e166b9626cbdb15437a0a1a02cf

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In Astronomy and Astrophysics

1. Jon Fortney
2. J. Owen
3. E. Lopez
4. C. Mordasini
5. Sara Seager
6. Yanqin Wu
7. Leslie A. Rogers
8. L. Kaltenegger

Citations in the corpus

• The Evaporation Valley in the Kepler Planets (2017, methodology): “(22) We further choose a0 = 0.5 and tsat = 100 Myrs, and Lsat ≈ 10−3.5L (M∗/M ), motivated by the body of observational and modelling works (e.g. Güdel et al. 1997; Ribas et al. 2005; Jackson et al. 2012; Tu et al. 2015).”
• THE ATMOSPHERIC SIGNATURES OF SUPER-EARTHS: HOW TO DISTINGUISH BETWEEN HYDROGEN-RICH AND HYDROGEN-POOR ATMOSPHERES (2008, background): “This is similar to what is known to occur in solar-type stars as they age, where UV flux reduces by a factor of 103 over their main-sequence lifetimes (Ribas et al. 2005).”
• DENSITY AND ECCENTRICITY OF KEPLER PLANETS (2012, background): “…when the stars were more chromospherically active and 8 Some of the stars have only recently become sub-giants but we ignore this complication here brighter in the FUV(see, e.g. Lammer et al. 2004; Ribas et al. 2005), and also when the planets were younger and fluffier (also see Lopez et al. 2012).”
• Mercury’s Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroidal Space Weathering Studies (2014, background): “The bolometric luminosity at zero-age main-sequence (ZAMS) was ∼70 % of its present output (Siess et al. 2000; Ribas et al. 2005), so the optical and infrared thermal outputs were 30 % lower than today.”
• Atmospheric Escape and Evolution of Terrestrial Planets and Satellites (2008, methodology): “To overcome this problem Ribas et al. (2005) inferred the total integrated flux in that interval by comparison with the flux evolution in the other wavelength ranges.”
• THE EVOLUTION OF SOLAR FLUX FROM 0.1 nm TO 160 μm: QUANTITATIVE ESTIMATES FOR PLANETARY STUDIES (2012, neutral): “The most comprehensive study is the “Sun in Time” program, which recently published multi-wavelength results from 20 years of telescopic observation of solar analogs—nearby G stars that are compositionally similar to the Sun but vary in age (Ribas et al. 2005, subsequently referred to as “R05”).”
• OBSERVATIONS OF MASS LOSS FROM THE TRANSITING EXOPLANET HD 209458b (2010, background): “For example, the Lymanα line contains more flux than the entire Lyman continuum (Ribas et al. 2005), and other UV emission lines and continuum radiation in the wavelength range 912–2000 Å can be absorbed in the bound-free continua of atomic species (e.g., CNO) and molecules including H2.”
• Planetary evaporation by UV and X‐ray radiation: basic hydrodynamics (2012, background): “…luminosities and X-ray luminosities seem to have similar values at earlier times during the T-Tauri phase (Alexander et al. 2004) and at late times (Ribas et al. 2005), perhaps - indicates fall off with time is similar, if not identical, (see also Sanz-Forcada et al. 2011), we make a simple…”
• What makes a planet habitable? (2009, positive): “In particular, solar-type stars stay at saturated emission levels until they age to ∼100 Myr, and then their X-ray luminosities rapidly decrease as a function of age following a power law relationship ∝ (t[Gyr])−1.72 (Ribas et al. 2005).”
• Outgassing History and Escape of the Martian Atmosphere and Water Inventory (2015, methodology): “…nebulae life times are <10 Myr (e.g., Lunine et al. 2011), the nebula-based hydrogen-rich martian protoatmosphere was most likely exposed during several tens of Myr or up to ∼150 Myr to an EUV flux which was ∼50–100 times higher compared to today’s Sun (Ribas et al. 2005; Claire et al. 2012).”
• How to Characterize Habitable Worlds and Signs of Life (2017, background): “Earth’s atmosphere has experienced dramatic evolution over 4.5 Gyr (e.g., Ribas et al. 2005, Zahnle et al. 2008).”
• THE MUSCLES TREASURY SURVEY. I. MOTIVATION AND OVERVIEW (2016, methodology): “While the need for panchromatic data has been realized for Sun-like stars (e.g., Sun in Time; Ribas et al. 2005), M dwarfs have received less attention (see also Guinan & Engle 2009), despite the fact that these systems dominate the planet statistics of the Galaxy.”
• ABIOTIC OXYGEN-DOMINATED ATMOSPHERES ON TERRESTRIAL HABITABLE ZONE PLANETS (2014, background): “Because XUV fluxes are greatly enhanced around young dwarf stars in general, total water loss could be many times this value in many cases (Ribas et al. 2005; Ribas et al. 2010; Linsky et al. 2014).”
• Composition and fate of short-period super-Earths: The case of CoRoT-7b (2009, positive): “…EUV photons emitted by the star, which is strongly dependent on the stellar age: FEUV = αt −β 9 a −2 1 , (2) according to recent observations of EUV emission from young stars (Ribas et al., 2005); where t9 is the stellar age in Ga, a1 the planet’s orbital distance in AU, and α and β are constants.”