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Observation data
Epoch J2000      Equinox J2000
Constellation Sagittiarus
Right ascension 18h 06m 7.44s[1]
Declination −31° 24′ 16.12″[1]
Spectral type KV[1]
Variable type unknown
Distance 7500 ± 2000[2] ly
(2300 ± 600[2] pc)
Mass 0.67+0.33
[2] M
Database references

MOA-2010-BLG-477L is a K-type star with about 0.67 times the mass of the Sun,[1] in the main-sequence phase of its stellar evolution.[1] Overall, very little is known about this star, with very poor constrains on its projected characteristics due to One extrasolar planet, with a mass greater than that of Jupiter, has been discovered orbiting the star at a distance of roughly 2 AU.[2] The planet was detected by means of microlensing,[1] where gravitational lensing as the planet and its host star pass in front of a background star causes a temporary flare in the amount of light observed, allowing the planet's existence to be known.[1]

Planetary system[edit]

The history of the detection of the planet, MOA-2010-BLG-477 L b, dates back to the year 2010. In that year, a microlensing alert event occurred, before the planet was confirmed conclusively, and was detected independently by the MOA and OGLE collaborations.[1] Following the original microlensing event, astronomers predicted another microlensing peak, which was observed by numerous groups using a wide array of telescopes.[1] One of these telescopes was located in Antarctica, and made the first microlensing detections from that continent; however, the data collected there were too crude to be included in the analysis which eventually confirmed the planet.[1]

MOA-2010-BLG-477 L b is the only planet which has been detected orbiting MOA-2010-BLG-477 L. Little is known about this planet, with the only characteristics known about this system are the mass of the planet and its projected separation from its host star.[2]

The MOA-2010-BLG-477L planetary system[2]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b 1.5−0.3+1.8 MJ 2−1+3


  1. ^ a b c d e f g h i j Bachelet, E.; Shin, I.-G.; Han, C.; Fouqué, P.; Gould, A.; Menzies, J. W.; Beaulieu, J.-P.; Bennett, D. P.; et al. (2012). "MOA-2010-BLG-477Lb: Constraining the mass of a microlensing planet from microlensing parallax, orbital motion and detection of blended light". Bibcode:2012ApJ...754...73B. arXiv:1205.6323Freely accessible. doi:10.1088/0004-637X/754/1/73. 
  2. ^ a b c d e f Schneider, Jean (2 June 2012). "Notes for Star MOA-2010-BLG-477L". The Extrasolar Planets Encyclopaedia.