“HR 5171 A”- the largest ever yellow hypergiant star discovered

The astronomers of Oliver Chesneau of the Cote d’Azur Observatory (Nice, France) discovered the largest Yellow star “HR 5171 A” in our Milky way Galaxy.

  • Technique used by astronomers: Interferometry that helps to combine the light collected from multiple individual telescopes, effectively creates a giant telescope up to 140 metres in size. 

About HR 5171 A star  

  • Also known as V766 Centauri, HD 119796 and HIP 67261.
  • A yellow hypergiant star in the constellation Centaurus.
  • Observed by the European Southern Observatory’s (ESO) Very Large Telescope Interferometer (VLTI).
  • About 12,000 light-years away from Earth and can be visible to the naked eye in the nighttime sky.
  • 1,300 times wider and 1,000,000 times brighter than Sun.
  • 50 times bigger than red supergiant Betelgeuse in the Orion constellation.
  • The star is in a binary system by studying the data contributed by several observatories and determined the system as an eclipsing binary star system with the smaller companion star orbiting the larger V766 Centauri once every 1300 days.

This new discovery highlights the importance of studying these huge and short-lived yellow hypergiants, and could provide a means of understanding the evolutionary processes of massive stars in general.
Note: Yellow hypergiants are extremely rare and approximately a dozen are known to exist in the Milky Way. In general, they are very unstable because of the stage of their ‘life’. The most well-known is Rho Cassiopeiae in the Cassiopeia constellation.