NML Cygni (also known as V1489 Cygni or IRC +40448) is a red hypergiant star in the constellation Cygnus. It is one of the largest known stars, however it is hard to determine the true radius of the star, due to the dust surrounding the star, but here we’ll put it at 1,500 Solar Radii as an upper limit. It is very similar to VY Canis Majoris, another red hypergiant star. NML Cygni has been cited as the largest known star in older sources. The “NML” part of its name is not a variable designation- it is the names of the three discoverers: Neugebauer, Martz, and Leighton.
Astronomical data
Radius (in Solar Radii): ~1,500 R☉ (Upper Limit)
Diameter (in Kilometers): 2,088,000,000 km
Mass (in Solar Masses): 25 M☉
Distance (in Light Years): 5,250 ly
Spectral type: M4.5 (Red)
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