NML Cygni

NML Cygni or V1489 Cygni is a red hypergiant star. It is one of the brightest supergiant stars. It was discovered in 1965, by Gerry Neugebauer, D.M. Martz and Robert Leighton. The name 'NML' comes from the names of the three discoverers.  

NML Cygni's distance from Earth is about 5,250 light-years. This star has dust surrounding it. It has a bean-shaped asymmetric nebula with water vapour. Schuster M.T; Humphreys R.M. & Marengo M. 2006. The circumstellar environments of NML Cygni and the cool hypergiants. The Astronomical Journal 131, 603.  It is a semiregular variable star. This means its brightness changes over 940 days.Schuster M.T. et al 2009. Imaging the cool hypergiant NML Cygni's dusty circumstellar envelope with adaptive optics. Astrophysical Journal 699 (2): 1423.  Considering its distance and an upper limit on the star's angular size, Data about NML Cygni is found here at VizieR. its physical radius must be less than 1,350 times that of the Sun.. The radius (R*) is given by:



This star is a part of the Cygnus OB2 association, which is 1.74 ± 0.2 kpc away. This is one of the nearest massive star groups to the Sun. This group includes some of the most massive and brightest stars known, including the suspected luminous blue variable Cyg OB2 #12. NML Cygni has lots of oxygen. Molecules like H2O, Silicon monoxide, carbon monoxide, hydrogen cyanide, carbon monosulfide, sulfur monoxide, sulfur dioxide and hydrogen sulfide are also in the star.

NML Cygni has two dense outer layers of dust and molecules. The star is also losing mass by slowly throwing gas into space.  The dust envelopes are formed by this process.

 References 

Category:Red giants
Category:Variable stars
Category:Hypergiants