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Title: Space Weathering of Super-Earths: Model Simulations of Exospheric Sodium Escape from 61 Virgo b

Abstract

Rocky exoplanets are expected to be eroded by space weather in a similar way as in the solar system. In particular, Mercury is one of the dramatically eroded planets whose material continuously escapes into its exosphere and further into space. This escape is well traced by sodium atoms scattering sunlight. Due to solar wind impact, micrometeorite impacts, photo-stimulated desorption and thermal desorption, sodium atoms are released from surface regolith. Some of these released sodium atoms are escaping from Mercury’s gravitational-sphere. They are dragged anti-Sun-ward and form a tail structure. We expect similar phenomena on exoplanets. The hot super-Earth 61 Vir b orbiting a G3V star at only 0.05 au may show a similar structure. Because of its small separation from the star, the sodium release mechanisms may be working more efficiently on hot super-Earths than on Mercury, although the strong gravitational force of Earth-sized or even more massive planets may be keeping sodium atoms from escaping from the planet. Here, we performed model simulations for Mercury (to verify our model) and 61 Vir b as a representative super-Earth. We have found that sodium atoms can escape from this exoplanet due to stellar wind sputtering and micrometeorite impacts, to form amore » sodium tail. However, in contrast to Mercury, the tail on this hot super-Earth is strongly aligned with the anti-starward direction because of higher light pressure. Our model suggests that 61 Vir b seems to have an exo-base atmosphere like that of Mercury.« less

Authors:
; ;  [1]
  1. Kiepenheuer Institute for Solar Physics, Schöneckstraße 6, 79104 Freiburg im Breisgau (Germany)
Publication Date:
OSTI Identifier:
22663150
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 154; Journal Issue: 4; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ATOMS; DESORPTION; EXOSPHERE; MERCURY; METEORITES; OVERBURDEN; PLANETS; SATELLITE ATMOSPHERES; SATELLITES; SCATTERING; SODIUM; SOLAR SYSTEM; SOLAR WIND; SPACE; SUN; SURFACES; VISIBLE RADIATION; WEATHERING

Citation Formats

Yoneda, M., Berdyugina, S., and Kuhn, J. Space Weathering of Super-Earths: Model Simulations of Exospheric Sodium Escape from 61 Virgo b. United States: N. p., 2017. Web. doi:10.3847/1538-3881/AA8307.
Yoneda, M., Berdyugina, S., & Kuhn, J. Space Weathering of Super-Earths: Model Simulations of Exospheric Sodium Escape from 61 Virgo b. United States. doi:10.3847/1538-3881/AA8307.
Yoneda, M., Berdyugina, S., and Kuhn, J. Sun . "Space Weathering of Super-Earths: Model Simulations of Exospheric Sodium Escape from 61 Virgo b". United States. doi:10.3847/1538-3881/AA8307.
@article{osti_22663150,
title = {Space Weathering of Super-Earths: Model Simulations of Exospheric Sodium Escape from 61 Virgo b},
author = {Yoneda, M. and Berdyugina, S. and Kuhn, J.},
abstractNote = {Rocky exoplanets are expected to be eroded by space weather in a similar way as in the solar system. In particular, Mercury is one of the dramatically eroded planets whose material continuously escapes into its exosphere and further into space. This escape is well traced by sodium atoms scattering sunlight. Due to solar wind impact, micrometeorite impacts, photo-stimulated desorption and thermal desorption, sodium atoms are released from surface regolith. Some of these released sodium atoms are escaping from Mercury’s gravitational-sphere. They are dragged anti-Sun-ward and form a tail structure. We expect similar phenomena on exoplanets. The hot super-Earth 61 Vir b orbiting a G3V star at only 0.05 au may show a similar structure. Because of its small separation from the star, the sodium release mechanisms may be working more efficiently on hot super-Earths than on Mercury, although the strong gravitational force of Earth-sized or even more massive planets may be keeping sodium atoms from escaping from the planet. Here, we performed model simulations for Mercury (to verify our model) and 61 Vir b as a representative super-Earth. We have found that sodium atoms can escape from this exoplanet due to stellar wind sputtering and micrometeorite impacts, to form a sodium tail. However, in contrast to Mercury, the tail on this hot super-Earth is strongly aligned with the anti-starward direction because of higher light pressure. Our model suggests that 61 Vir b seems to have an exo-base atmosphere like that of Mercury.},
doi = {10.3847/1538-3881/AA8307},
journal = {Astronomical Journal (Online)},
number = 4,
volume = 154,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 2017},
month = {Sun Oct 01 00:00:00 EDT 2017}
}