Pr0211

Pr0211 (sometimes written Pr 0211, also 2MASS J08421149+1916373) is a Sun-like late G or early K-type main-sequence star in the Beehive Cluster, or Praesepe, located 600 light-years away in the constellation Cancer. It is rotationally variable and has a rotation period of 7.97 days,^[3] with its spin axis at an inclination of 76°±11° to the plane of the sky.^[7] Pr0211 hosts two known exoplanets, and was the first multi-planet system to be discovered in an open cluster.^[5][7]

Pr0211 forms a double star system with a K-type main-sequence star known as NGC 2632 JC 280 or 2MASS J08421285+1916040.^[9][10][11] Although the stars share a similar distance and common proper motion, their relative space velocity appears to be high enough that the pair are not gravitationally bound.^[9]

Pr0211 b is a gas giant exoplanet, specifically a hot Jupiter, orbiting around Pr0211. Pr0211 b along with Pr0201 b are notable for being the first exoplanets discovered in the Beehive Cluster.^[12][13] Pr0211 b and Pr0201 b were discovered in 2012 by Sam Quinn^[12][13][5] and his colleagues while observing 53 stars in the Beehive Cluster using the 1.5 metres (4.9 ft; 1.6 yd) telescope at the University of Georgia in the United States.^[12]

Pr0211 c is a gas giant exoplanet orbiting around Pr0211.^[14] Pr0211 c was discovered in 2016 by Luca Malavolta^[14][7] and his colleagues while observing its host star with the HARPS-N spectrograph on the 3.6 metres (12 ft; 3.9 yd) Italian Telescopio Nazionale Galileo (TNG) in La Palma, and the Tillinghast Reflector Echelle Spectrograph (TRES) mounted at the 1.5 metres (4.9 ft; 1.6 yd) telescope at the University of Georgia in the United States.