Are extrasolar Einstein’s spinning tops habitable?. (arXiv:2012.14245v2 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Iorio_L/0/1/0/all/0/1">Lorenzo Iorio</a>
Recently, the possibility that putative massive natural satellites (exomoons)
of extrasolar Jupiter-like giant planets orbiting main sequence stars may be
habitable has gained increasing attention. Typically, such an exomoon is
expected to orbit its parent planet in the equatorial plane of the latter, with
its spin $boldsymbol S$ aligned with its orbital angular momentum $boldsymbol
L$ which, in turn, is parallel to the planetary spin $boldsymbol J$. If, in
particular, the common tilt of such angular momenta to the satellite-planet
ecliptic plane, assumed fixed, has certain values, the overall irradiation
experienced by the exomoon from the star may allow it to sustain life as we
know it, at least for certain orbital configurations. A telluric body orbiting
different gaseous giant primaries at $5-10$ planetary radii $R$ whose spin is
initially tilted to the ecliptic by the same angle $varepsilon_0=23.44^circ$
as Earth is considered. Here, I show that, by allowing more or less large
departures from the merely ideal condition of exact alignment of $boldsymbol
S,,boldsymbol L,,boldsymbol J$, the general relativistic de Sitter and
Lense-Thirring precessions of the satellite’s spin due to the post-Newtonian
(pN) field of the host planet may have a non-negligible impact on the exomoon’s
habitability through induced long-term variations
$Deltavarepsilonleft(tright)$ of the obliquity $varepsilon$ of the
satellite’s spin $boldsymbol S$ to the ecliptic plane which may be as large as
tens of degrees over $simeq 0.1-1$ millions of years.
Recently, the possibility that putative massive natural satellites (exomoons)
of extrasolar Jupiter-like giant planets orbiting main sequence stars may be
habitable has gained increasing attention. Typically, such an exomoon is
expected to orbit its parent planet in the equatorial plane of the latter, with
its spin $boldsymbol S$ aligned with its orbital angular momentum $boldsymbol
L$ which, in turn, is parallel to the planetary spin $boldsymbol J$. If, in
particular, the common tilt of such angular momenta to the satellite-planet
ecliptic plane, assumed fixed, has certain values, the overall irradiation
experienced by the exomoon from the star may allow it to sustain life as we
know it, at least for certain orbital configurations. A telluric body orbiting
different gaseous giant primaries at $5-10$ planetary radii $R$ whose spin is
initially tilted to the ecliptic by the same angle $varepsilon_0=23.44^circ$
as Earth is considered. Here, I show that, by allowing more or less large
departures from the merely ideal condition of exact alignment of $boldsymbol
S,,boldsymbol L,,boldsymbol J$, the general relativistic de Sitter and
Lense-Thirring precessions of the satellite’s spin due to the post-Newtonian
(pN) field of the host planet may have a non-negligible impact on the exomoon’s
habitability through induced long-term variations
$Deltavarepsilonleft(tright)$ of the obliquity $varepsilon$ of the
satellite’s spin $boldsymbol S$ to the ecliptic plane which may be as large as
tens of degrees over $simeq 0.1-1$ millions of years.
http://arxiv.org/icons/sfx.gif
