Merope , designated 23 Tauri (abbreviated 23 Tau), is a

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

of Taurus and a member of the Pleiades

star cluster Star clusters are large groups of stars. Two main types of star clusters can be distinguished: globular clusters are tight groups of ten thousand to millions of old stars which are gravitationally bound, while open clusters are more loosely clust ...

. It is approximately away.

Distance

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 ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial obj ...

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 In Greek mythology, Gaia (; from Ancient Greek , a poetical form of , 'land' or 'earth'),, , . also spelled Gaea , is the personification of the Earth and one of the Greek primordial deities. Gaia is the ancestral mother—sometimes parthenog ...

. 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.

Description

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.''''Merope'', ''Star Names and their Meanings'', Richard Hinckley Allen, Dover Publications, 1963, p. 407. It has a

luminosity Luminosity is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object over time. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a st ...

of 927 times that of the Sun and a surface temperature of . Merope's mass is roughly and has a radius more than 7 times as great as the Sun's. It is classified as a Beta Cephei type variable star and its brightness varies by 0.01 magnitudes. It is given the variable star designation of V971 Tauri. Some papers have reported a companion star to Merope, at a separation of , as well as several other visual companions farther out. These possible companions have not been confirmed. Surrounding Merope is the Merope Nebula (NGC 1435). It appears brightest around Merope and is listed in the Index Catalogue as number IC 349.

Nomenclature

''23 Tauri'' is the star's Flamsteed designation. The name '' Merope'' originates with Greek mythology; she is one of the seven daughters of Atlas and Pleione known as

the Pleiades The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance of ...

. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Merope'' for this star. It is now so entered in the IAU Catalog of Star Names.

References

External links

*Jim Kaler's Stars, University of Illinoi
Merope (23 Tauri)
LRGB image with 4 hours total exposure. {{DEFAULTSORT:Merope (star) Tauri, 023 Taurus (constellation) Beta Cephei variables Pleiades Open Cluster B-type subgiants Merope

1156 Year 1156 ( MCLVI) was a leap year starting on Sunday (link will display the full calendar) of the Julian calendar. Events By place Levant * Spring – Raynald of Châtillon, prince of Antioch, makes an alliance with Thoros II (t ...

017608 023480 Durchmusterung objects ? Tauri, V971