Tidal radii of main sequence stars — III. Partial disruptions. (arXiv:1909.04041v1 [astro-ph.SR])

Tidal radii of main sequence stars — III. Partial disruptions. (arXiv:1909.04041v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ryu_T/0/1/0/all/0/1">Taeho Ryu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krolik_J/0/1/0/all/0/1">Julian Krolik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piran_T/0/1/0/all/0/1">Tsvi Piran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Noble_S/0/1/0/all/0/1">Scott C. Noble</a>

In this paper, the third in this series, we continue our study of tidal
disruption events of main-sequence stars by a non-spinning
$10^{6}~rm{M}_odot$ supermassive black hole. Here we focus on the outcomes of
partial disruptions. As the encounter becomes weaker, the debris mass is
increasingly concentrated near the outer edges of the energy distribution. As a
result, the mass fallback rate can deviate substantially from a $t^{-5/3}$
power-law, becoming more like a single peak with a tail declining as $t^{-p}$
with $psimeq2-5$. Surviving remnants are spun-up in the prograde direction and
are hotter than MS stars of the same mass. Their specific orbital energy is
$simeq10^{-3}times$ that of the debris (but of either sign with respect to
the black hole potential) while their specific angular momentum is close to
that of the original star. Even for strong encounters, remnants have speeds at
infinity relative to the black hole potential $lesssim 300$ km s$^{-1}$, so
they are unable to travel far out into the galactic bulge. Remnants bound to
the black hole can possibly go through a second tidal disruption event.

In this paper, the third in this series, we continue our study of tidal
disruption events of main-sequence stars by a non-spinning
$10^{6}~rm{M}_odot$ supermassive black hole. Here we focus on the outcomes of
partial disruptions. As the encounter becomes weaker, the debris mass is
increasingly concentrated near the outer edges of the energy distribution. As a
result, the mass fallback rate can deviate substantially from a $t^{-5/3}$
power-law, becoming more like a single peak with a tail declining as $t^{-p}$
with $psimeq2-5$. Surviving remnants are spun-up in the prograde direction and
are hotter than MS stars of the same mass. Their specific orbital energy is
$simeq10^{-3}times$ that of the debris (but of either sign with respect to
the black hole potential) while their specific angular momentum is close to
that of the original star. Even for strong encounters, remnants have speeds at
infinity relative to the black hole potential $lesssim 300$ km s$^{-1}$, so
they are unable to travel far out into the galactic bulge. Remnants bound to
the black hole can possibly go through a second tidal disruption event.

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