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Eridanus II
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<a href="/facts/Celestial_coordinate_system/23HhqvHj">Coordinates</a>: <a href="http://www.wikisky.org/?ra=3.7389166666667&de=-43.533805555556&zoom=7&show_grid=1&show_constellation_lines=1&show_constellation_boundaries=1&show_const_names=1&show_galaxies=1&img_source=IMG_all">03h 44m 20.1s, −43° 32′ 01.7″</a> <p>The Eridanus II Dwarf is a <a href="/facts/Low-surface-brightness_galaxy/6bE09r46">low-surface brightness</a> <a href="/facts/Dwarf_galaxy/TKS7W9tA">dwarf galaxy</a> in the <a href="/facts/Constellation/nBQqgW8A">constellation</a> <a href="/facts/Eridanus_(constellation)/cvtlSUun">Eridanus</a>. Eridanus II was independently discovered by two groups in 2015, using data from the <a href="/facts/Dark_Energy_Survey/fUEynWa7">Dark Energy Survey</a> (Bechtol et al., 2015; Koposov et al. 2015). This <a href="/facts/Galaxy/zCyUvEf7">galaxy</a> is probably a distant satellite of the <a href="/facts/Milky_Way/ulF6lccN">Milky Way</a> (Li et al., 2016). Eridanus II contains a centrally located <a href="/facts/Globular_cluster/FL0EERJU">globular cluster</a>; and is the smallest, least luminous galaxy known to contain a globular cluster. Crnojević et al., 2016. Eridanus II is significant, in a general sense, because the widely accepted <a href="/facts/Lambda-CDM_model/DmlhJHQU">Lambda CDM cosmology</a> predicts the existence of many more dwarf galaxies than have yet been observed. The search for just such bodies was one of the motivations for the ongoing <a href="/facts/Dark_Energy_Survey/fUEynWa7">Dark Energy Survey</a> observations. Eridanus II has special significance because of its apparently stable globular cluster. The stability of this cluster, near the center of such a small, diffuse, galaxy places constraints on the nature of <a href="/facts/Dark_matter/y5HgX55N">dark matter</a> (Brandt 2016; Li et al., 2016). </p>