Merope (star)

Merope /ˈmɛrəpiː/, designated 23 Tauri (abbreviated 23 Tau), is a star in the constellation of Taurus and a member of the Pleiades star cluster. It is approximately 440 light-years (135 pc) away. Despite being one of the closest star clusters to Earth, the distance to the Pleiades and its member stars is still in dispute. The parallax of Merope itself is not known precisely enough to give an accurate distance. Its Hipparcos parallax has a statistical margin of error of about 5% and gave a distance 116 parsecs. This, and an overall distance to the Pleiades calculated from Hipparcos parallaxes of 120 parsecs, are inconsistent with other parallax measurements such as from Gaia. Merope is too bright for Gaia to have a reliable parallax for it, but calculations of the overall distance to the Pleiades cluster using Hipparcos, Gaia, Hubble Space Telescope, and other methods repeatedly show that the Hipparcos parallaxes suffered from some kind of systemic error, and the distance to the Pleiades is most likely around 135 parsecs. Merope is a blue-white B-type subgiant with a mean apparent magnitude of +4.18. Richard Hinckley Allen described the star as lucid white and violet. It has a luminosity 927 times that of the Sun and a surface temperature of 14,550 K. Merope's mass is roughly 4.25 M☉ and has a radius 4.8 times as great as the Sun's.