Unseen companions of V Hya inferred from periodic ejections. (arXiv:1902.08206v2 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Salas_J/0/1/0/all/0/1">Jesus M. Salas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Naoz_S/0/1/0/all/0/1">Smadar Naoz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morris_M/0/1/0/all/0/1">Mark R. Morris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stephan_A/0/1/0/all/0/1">Alexander P. Stephan</a>

A recent study using $Hubble$ $Space$ $Telescope$ observations found
periodic, high-speed, collimated ejections (or “bullets”) from the star V Hya.
The authors of that study proposed a model associating these bullets with the
periastron passage of an unseen, substellar companion in an eccentric orbit and
with an orbital period of $sim8$ yrs. Here we propose that V Hya is part of a
triple system, with a substellar companion having an orbital period of $sim8$
yrs, and a tertiary object on a much wider orbit. In this model, the more
distant object causes high-eccentricity excitations on the substellar
companion’s orbit via the Eccentric Kozai-Lidov mechanism. These eccentricities
can reach such high values that they lead to Roche-lobe crossing, producing the
observed bullet ejections via a strongly enhanced accretion episode. For
example, we find that a ballistic bullet ejection mechanism can be produced by
a brown-dwarf-mass companion, while magnetically driven outflows are consistent
with a Jovian-mass companion. Finally, we suggest that the distant companion
may reside at few a hundred AU on an eccentric orbit.

A recent study using $Hubble$ $Space$ $Telescope$ observations found
periodic, high-speed, collimated ejections (or “bullets”) from the star V Hya.
The authors of that study proposed a model associating these bullets with the
periastron passage of an unseen, substellar companion in an eccentric orbit and
with an orbital period of $sim8$ yrs. Here we propose that V Hya is part of a
triple system, with a substellar companion having an orbital period of $sim8$
yrs, and a tertiary object on a much wider orbit. In this model, the more
distant object causes high-eccentricity excitations on the substellar
companion’s orbit via the Eccentric Kozai-Lidov mechanism. These eccentricities
can reach such high values that they lead to Roche-lobe crossing, producing the
observed bullet ejections via a strongly enhanced accretion episode. For
example, we find that a ballistic bullet ejection mechanism can be produced by
a brown-dwarf-mass companion, while magnetically driven outflows are consistent
with a Jovian-mass companion. Finally, we suggest that the distant companion
may reside at few a hundred AU on an eccentric orbit.

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