47 Ursae Majoris

Stellar classification



  • X -1
  • Y 41
  • Z -20
→ Sol: 46

Object type

  • High proper-motion Star
  • Star
  • Infra-Red source
  • UV-emission source
simbad:* 47 UMa


47 Ursae Majoris (abbreviated 47 UMa), also named Chalawan (Thai: ชาละวัน, pronounced [t͡ɕʰāː.lā.wān]), is a yellow dwarf star approximately 46 light-years from Earth in the constellation of Ursa Major. As of 2011, three extrasolar planets (designated 47 Ursae Majoris b, c and d; the first two later named Taphao Thong and Taphao Kaew) are believed to orbit the star.

The star is located fairly close to the Solar System: according to astrometric measurements made by the Hipparcos astrometry satellite, it exhibits a parallax of 71.11 milliarcseconds, corresponding to a distance of 45.913 light-years. With an apparent magnitude of +5.03, it is visible to the naked eye and its absolute magnitude of +4.29 implies a visual luminosity around 60% greater than the Sun. A solar analog, with a spectral type of G1V, it has a similar mass to that of the Sun but is slightly hotter at around 5,882 K. and slightly more metal-rich with around 110% of the solar abundance of iron.

Like the Sun, 47 Ursae Majoris is on the main sequence, converting hydrogen to helium in its core by nuclear fusion. Based on its chromospheric activity, the star may be around 6,000 million years old, though evolutionary models suggest an older age of around 8,700 million years. Other studies have yielded estimates of 4,400 and 7,000 million years for the star.

This article uses material from the Wikipedia article "47 Ursae Majoris", which is released under the Creative Commons Attribution-Share-Alike License 3.0.