Search for L5 Earth Trojans with DECam. (arXiv:2001.08229v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Markwardt_L/0/1/0/all/0/1">Larissa Markwardt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gerdes_D/0/1/0/all/0/1">David W. Gerdes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Malhotra_R/0/1/0/all/0/1">Renu Malhotra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Becker_J/0/1/0/all/0/1">Juliette C. Becker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hamilton_S/0/1/0/all/0/1">Stephanie J. Hamilton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Adams_F/0/1/0/all/0/1">Fred C. Adams</a>

Most of the major planets in the Solar System support populations of
co-orbiting bodies, known as Trojans, at their L4 and L5 Lagrange points. In
contrast, Earth has only one known co-orbiting companion. This paper presents
the results from a search for Earth Trojans using the DECam instrument on the
Blanco Telescope at CTIO. This search found no additional Trojans in spite of
greater coverage compared to previous surveys of the L5 point. Therefore, the
main result of this work is to place the most stringent constraints to date on
the population of Earth Trojans. These constraints depend on assumptions
regarding the underlying population properties, especially the slope of the
magnitude distribution (which in turn depends on the size and albedo
distributions of the objects). For standard assumptions, we calculate upper
limits to a 90% confidence limit on the L5 population of $N_{ET}<1$ for magnitude $H<15.5$, $N_{ET}=60-85$ for $H<19.7$, and $N_{ET} $= 97 for $H=20.4$. This latter magnitude limit corresponds to Trojans $sim$300 m in size for albedo $0.15$. At H=19.7, these upper limits are consistent with previous L4 Earth Trojan constraints and significantly improve L5 constraints.

Most of the major planets in the Solar System support populations of
co-orbiting bodies, known as Trojans, at their L4 and L5 Lagrange points. In
contrast, Earth has only one known co-orbiting companion. This paper presents
the results from a search for Earth Trojans using the DECam instrument on the
Blanco Telescope at CTIO. This search found no additional Trojans in spite of
greater coverage compared to previous surveys of the L5 point. Therefore, the
main result of this work is to place the most stringent constraints to date on
the population of Earth Trojans. These constraints depend on assumptions
regarding the underlying population properties, especially the slope of the
magnitude distribution (which in turn depends on the size and albedo
distributions of the objects). For standard assumptions, we calculate upper
limits to a 90% confidence limit on the L5 population of $N_{ET}<1$ for
magnitude $H<15.5$, $N_{ET}=60-85$ for $H<19.7$, and $N_{ET} $= 97 for
$H=20.4$. This latter magnitude limit corresponds to Trojans $sim$300 m in
size for albedo $0.15$. At H=19.7, these upper limits are consistent with
previous L4 Earth Trojan constraints and significantly improve L5 constraints.

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