Ultraviolet radiation constraints around the circumstellar habitable zones

Buccino, A. P.; Lemarchand, Guillermo A.; Mauas, P. J. D.

doi:10.1016/j.icarus.2006.03.007

Cited by 85 publications

(73 citation statements)

References 59 publications

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“…Other choices are possible and values from 1 to 5 Gyr are adopted in literature (see e.g. Schopf 1993; Turnbull & Tarter 2003;Buccino et al 2006). …”

Section: Methodsmentioning

confidence: 99%

Evolution of the habitable zone of low-mass stars

Valle

Dell’Omodarme

Moroni

et al. 2014

A&A

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Context. The habitability of an exoplanet is assessed by determining the times at which its orbit lies in the circumstellar habitable zone (HZ). This zone evolves with time following the stellar luminosity variation, which means that the time spent in the HZ depends on the evolution of the host star. Aims. We study the temporal evolution of the HZ of low-mass stars -only due to stellar evolution -and evaluate the related uncertainties. These uncertainties are then compared with those due to the adoption of different climate models. Methods. We computed stellar evolutionary tracks from the pre-main sequence phase to the helium flash at the red-giant branch tip for stars with masses in the range [0.70−1.10] M , metallicity Z in the range [0.005−0.04], and various initial helium contents. By adopting a reference scenario for the HZ computations, we evaluated several characteristics of the HZ, such as the distance from the host star at which the habitability is longest, the duration of this habitability, the width of the zone for which the habitability lasts one half of the maximum, and the boundaries of the continuously habitable zone (CHZ) for which the habitability lasts at least 4 Gyr. We developed analytical models, accurate to the percent level or lower, which allowed to obtain these characteristics in dependence on the mass and the chemical composition of the host star. Results. The metallicity of the host star plays a relevant role in determining the HZ. The importance of the initial helium content is evaluated here for the first time; it accounts for a variation of the CHZ boundaries as large as 30% and 10% in the inner and outer border. The computed analytical models allow the first systematic study of the variability of the CHZ boundaries that is caused by the uncertainty in the estimated values of mass and metallicity of the host star. An uncertainty range of about 30% in the inner boundary and 15% in the outer one were found. We also verified that these uncertainties are larger than that due to relying on recently revised climatic models, which leads to a CHZ boundary shift within ±5% with respect to those of our reference scenario. We made an on-line tool available that provides both HZ characteristics and interpolated stellar tracks.

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“…Other choices are possible and values from 1 to 5 Gyr are adopted in literature (see e.g. Schopf 1993; Turnbull & Tarter 2003;Buccino et al 2006). …”

Section: Methodsmentioning

confidence: 99%

Evolution of the habitable zone of low-mass stars

Valle

Dell’Omodarme

Moroni

et al. 2014

A&A

View full text Add to dashboard Cite

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“…On the other hand UV could be also a factor necessary for life origin and biological evolution. Therefore, UV radiation should also be considered as an habitability criteria (Buccino et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Flares and habitability

2011

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Abstract. At present, dwarf M stars are being considered as potential hosts for habitable planets. However, an important fraction of these stars are flare stars, which among other kind of radiation, emit large amounts of UV radiation during flares, and it is unknown how this events can affect life, since biological systems are particularly vulnerable to UV. In this work we evaluate a well known dMe star, EV Lacertae (GJ 873) as a potential host for the emergence and evolution of life, focusing on the effects of the UV emission associated with flare activity. Since UV-C is particularly harmful for living organisms, we studied the effect of UV-C radiation on halophile archaea cultures. The halophile archaea or haloarchaea are extremophile microorganisms, which inhabit in hypersaline environments and which show several mechanisms to cope with UV radiation since they are naturally exposed to intense solar UV radiation on Earth. To select the irradiance to be tested, we considered a moderate flare on this star. We obtained the mean value for the UV-C irradiance integrating the IUE spectrum in the impulsive phase, and considering a hypothetical planet in the center of the liquid water habitability zone. To select the irradiation times we took the most frequent duration of flares on this star which is from 9 to 27 minutes. Our results show that even after considerable UV damage, the haloarchaeal cells survive at the tested doses, showing that this kind of life could survive in a relatively hostile UV environment.

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“…The Galactic HZ (Lineweaver et al, 2004) caters to the requirement that a sufficient amount of heavy elements (notably those contained in carbon and silicate compounds) must be present for the build-up of planets and life, a condition easily met in the solar neighborhood. The UV-HZ (Buccino et al, 2006;Cuntz et al, 2008) is based on the premise that no lethal amounts of stellar UV flux is produced (regarding life forms assuming carbon-based biochemistry), a condition that tends to favor the environment of old main-sequence stars and giants (Guinan and Ribas, 2002) as well as planets with appreciable atmospheres, notable significant ozone layers (Segura et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Habitability of Super-Earth Planets Around Other Suns: Models Including Red Giant Branch Evolution

et al. 2009

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The unexpected diversity of exoplanets includes a growing number of super-Earth planets, i.e., exoplanets with masses of up to several Earth masses and a similar chemical and mineralogical composition as Earth. We present a thermal evolution model for a 10 Earth mass planet orbiting a star like the Sun. Our model is based on the integrated system approach, which describes the photosynthetic biomass production taking into account a variety of climatological, biogeochemical, and geodynamical processes. This allows us to identify a so-called photosynthesissustaining habitable zone (pHZ) determined by the limits of biological productivity on the planetary surface. Our model considers the solar evolution during the main-sequence stage and along the Red Giant Branch as described by the most recent solar model. We obtain a large set of solutions consistent with the principal possibility of life. The highest likelihood of habitability is found for "water worlds". Only mass-rich water worlds are able to realize pHZ-type habitability beyond the stellar main-sequence on the Red Giant Branch.4

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Ultraviolet radiation constraints around the circumstellar habitable zones

Cited by 85 publications

References 59 publications

Evolution of the habitable zone of low-mass stars

Evolution of the habitable zone of low-mass stars

Flares and habitability

Habitability of Super-Earth Planets Around Other Suns: Models Including Red Giant Branch Evolution

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