A Possible Third Body in the X-Ray System GRS 1747-312 and Models with Higher-Order Multiplicity. (arXiv:2310.11500v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Painter_C/0/1/0/all/0/1">Caleb Painter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stefano_R/0/1/0/all/0/1">Rosanne Di Stefano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kashyap_V/0/1/0/all/0/1">Vinay L. Kashyap</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Soria_R/0/1/0/all/0/1">Roberto Soria</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lopez_Miralles_J/0/1/0/all/0/1">Jose Lopez-Miralles</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Urquhart_R/0/1/0/all/0/1">Ryan Urquhart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Steiner_J/0/1/0/all/0/1">James F. Steiner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Motta_S/0/1/0/all/0/1">Sara Motta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ragozzine_D/0/1/0/all/0/1">Darin Ragozzine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mori_H/0/1/0/all/0/1">Hideyuki Mori</a>
GRS 1747-312 is a bright Low-Mass X-ray Binary in the globular cluster Terzan
6, located at a distance of 9.5 kpc from the Earth. It exhibits regular
outbursts approximately every 4.5 months, during which periodic eclipses are
known to occur. These eclipses have only been observed in the outburst phase,
and are not clearly seen when the source is quiescent. Recent Chandra
observations of the source were performed in June 2019 and April, June, and
August of 2021. Two of these observations captured the source during its
outburst, and showed clear flux decreases at the expected time of eclipse. The
other two observations occurred when the source was quiescent. We present the
discovery of a dip that occurred during the quiescent state. The dip is of
longer duration and its time of occurrence does not fit the ephemeris of the
shorter eclipses. We study the physical characteristics of the dip and
determine that it has all the properties of an eclipse by an object with a well
defined surface. We find that there are several possibilities for the nature of
the object causing the 5.3 ks eclipse. First, GRS 1747-312 may be an X-ray
triple, with an LMXB orbited by an outer third object, which could be an
M-dwarf, brown dwarf, or planet. Second, there could be two LMXBs in close
proximity to each other, likely bound together. Whatever the true nature of the
eclipser, its presence suggests that the GRS 1747-312 system is unique.
GRS 1747-312 is a bright Low-Mass X-ray Binary in the globular cluster Terzan
6, located at a distance of 9.5 kpc from the Earth. It exhibits regular
outbursts approximately every 4.5 months, during which periodic eclipses are
known to occur. These eclipses have only been observed in the outburst phase,
and are not clearly seen when the source is quiescent. Recent Chandra
observations of the source were performed in June 2019 and April, June, and
August of 2021. Two of these observations captured the source during its
outburst, and showed clear flux decreases at the expected time of eclipse. The
other two observations occurred when the source was quiescent. We present the
discovery of a dip that occurred during the quiescent state. The dip is of
longer duration and its time of occurrence does not fit the ephemeris of the
shorter eclipses. We study the physical characteristics of the dip and
determine that it has all the properties of an eclipse by an object with a well
defined surface. We find that there are several possibilities for the nature of
the object causing the 5.3 ks eclipse. First, GRS 1747-312 may be an X-ray
triple, with an LMXB orbited by an outer third object, which could be an
M-dwarf, brown dwarf, or planet. Second, there could be two LMXBs in close
proximity to each other, likely bound together. Whatever the true nature of the
eclipser, its presence suggests that the GRS 1747-312 system is unique.
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