Impact of the Solar System's passage through dark molecular clouds: a case of local habitability
DOI:
https://doi.org/10.47456/Cad.Astro.v4n2.38783Keywords:
Habitability, molecular clouds, astrobiologyAbstract
Molecular clouds (MC) are non-homogeneous, neutral regions, with volumetric densities ranging from 102 cm-3 to 108 cm-3, visible extinctions up to 30 mag, and temperatures ranging from 10 to 100 K. The Solar System lies in a low-density plasma bubble, surrounded by dark MC distributed in a radius of ~ 100 pc. In its motion in the Galactic plane, the Solar System must traverse one or more of these regions at each orbit around the galactic center. This paper discusses the impact of the Sun being immersed in an MC and analyzes the effects of solar radiation that hits the Earth as a function of the density of the region traversed. For MC volumetric densities in the order of 104 cm-3, the ionization front reaches a region of 1 astronomical unit (UA) in about 2 days. If the density is greater than 106 cm-3, all ionizing UV photons are consumed in a spherical volume with radius less than 1 UA, significantly cooling the Earth in its trajectory around the Sun. If the SS enters an interstellar cloud with a density greater than or equal to 107 cm-3, the UV radiation (that reaches Earth in approximately 300 days will be blocked) or it may remain in this state indefinitely if the cloud density is higher. Under these conditions, the Earth would come into existence in an environment with characteristics of the Interstellar Environment, which would have catastrophic consequences for the planet's climate.
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References
P. C. Frisch et al., The galactic environment of the Sun: Interstellar material inside and outside of the heliosphere, Space Sci. Rev. 146(1-4), 235 (2009).
S. J. Lallemant et al., Accretionary wedge growth and the limit of the seismogenic zone., AGU Fall Meeting Abstracts T14A-08 (2008).
D. A. Machaieie et al., Properties of Dense Cores Embedded in Musca Derived from Extinction Maps and 13CO, C18O, and NH3 Emission Lines, Astrophys. J. 836(1), 19 (2017).
R. C. Bohlin, B. D. Savage e J. F. Drake, A survey of interstellar H I from Ly-α absorption measurements. II., Astrophys. J. 224, 132 (1978).
C. Fröhlich e J. Lean, Solar radiative output and its variability: evidence and mechanisms, The Astronomy and Astrophysics Review 12(4), 273 (2004).
G. A. Meehl et al., Amplifying the Pacific climate system response to a small 11-year solar cycle forcing, Science 325(5944), 1114 (2009).
I. Ribas, The Sun and stars as the primary energy input in planetary atmospheres, Proceedings of the International Astronomical Union 5(S264), 3 (2009).
A. Kosovichev, A. Andrei e J.-P. Roelot, Solar and Stellar Variability: Impact on Earth and Planets, Proceedings of The International Astronomical Union 264 (2010).
S. K. Yi, Y.-C. Kim e P. Demarque, The Y2 Stellar Evolutionary Tracks, Astrophys. J. Supp. 144, 259 (2003). ArXiv:astro-ph/ 0210201.
Y.-C. Kim et al., The Y2 isochrones for α-element enhanced mixtures, Astrophys. J. Supp. 143(2), 499 (2002).
B. Paxton et al., Modules for Experiments in Stellar Astrophysics (MESA), Astrophys. J. Supp. 192(1), 3 (2011). ArXiv:1009.1622.
B. Paxton et al., Modules for Experiments in Stellar Astrophysics (MESA): Planets, Oscillations, Rotation, and Massive Stars, Astrophys. J. Supp. 208(1), 4 (2013). ArXiv: 1301.0319.
B. Paxton et al., Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions, Astrophys. J. Supp. 220(1), 15 (2015). ArXiv:1506.03146.
B. Paxton et al., Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions, Astrophys. J. Supp. 234(2), 34 (2018). ArXiv:1710.08424.
B. Paxton et al., Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation, Astrophys. J. Supp. 243(1), 10 (2019). ArXiv:1903. 01426.
A. S. Jermyn et al., Modules for Experiments in Stellar Astrophysics (MESA): Time-Dependent Convection, Energy Conservation, Automatic Differentiation, and Infrastructure, arXiv e-prints arXiv:2208.03651 (2022). ArXiv:2208.03651.
T. R. Ayres, Evolution of the solar ionizing flux, Journal of Geophysical Research: Planets 102(E1), 1641 (1997).
I. Ribas et al., Evolution of the solar activity over time and effects on planetary atmospheres. I. High-energy irradiances (1-1700 Å), Astrophys. J. 622(1), 680 (2005).
P. Lemaire et al., Flare observation of the Sun as a star by SUMER/SOHO in the hydrogen Lyman continuum, Astron. Astrophys. 418(2), 737 (2004).
L. Spitzer, Physics of fully ionized gases (Courier Corporation, 2006).
A. Raga, J. Cantó e L. Rodríguez, Analytic and numerical models for the expansion of a compact HII region, Mon. Not. R. Astron. Soc. 419(1), L39 (2012).
A. Raga, J. Cantó e L. Rodríguez, New analytic and quasi-analytic solutions for wind-driven compact HII regions, Revista Mexicana de Astronomía y Astrofísica 48(2), 199 (2012).
B. E. Wood et al., Measured mass-loss rates of solar-like stars as a function of age and activity, Astrophys. J. 574(1), 412 (2002).
E. Keto, On the evolution of ultracompact H II regions, Astrophys. J. 580(2), 980 (2002).
E. Keto, The formation of massive stars by accretion through trapped hypercompact H II regions, Astrophys. J. 599(2), 1196 (2003).
A. Raga, J. Cantó e A. Rodriguez-Gonzalez, The physics of the interstellar medium (UNAM, 2020). Disponível em https://bigbang.nucleares.unam.mx/ astroplasmas/images/stories/pdf/ libro-mi.pdf, acesso em jun. 2023.
M. Wild et al., The energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models, Climate Dynamics 44(11), 3393 (2015).
P. C. Frisch e H.-R. Mueller, Time-variability in the interstellar boundary conditions of the heliosphere: Effect of the solar journey on the galactic cosmic ray flux at Earth, Space Science Reviews 176(1), 21 (2013). ArXiv:1010.4507.
G. P. Zank et al., Heliospheric variation in response to changing interstellar environments, in Solar journey: The significance of our galactic environment for the heliosphere and earth, editado por P. C. Frisch (Springer, Dordrecht, 2006), 23–51.
N. Altobelli, E. Grün e M. Landgraf, A new look into the Helios dust experiment data: presence of interstellar dust inside the Earth’s orbit, Astronomy & Astrophysics 448(1), 243 (2006).
P. Frisch e D. G. York, Interstellar clouds near the Sun., in The Galaxy and the Solar System, editado por R. Smoluchowski, J. M. Bahcall e M. S. Matthews (University of Arizona Press, Tucson, 1986), 83–100.
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Copyright (c) 2023 Jurandi Leão, Thays Bentes, Carlos Alexandre Wuensche, José Williams
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