VY Canis Majoris

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Star
VY Canis Majoris
Image of the star and the surrounding gas cloud with the Hubble Space Telescope
Image of the star and the surrounding gas cloud with the Hubble Space Telescope
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Big dog
Right ascension 07 h 22 m 58.33 s
declination −25 ° 46 ′ 3.2 ″
Apparent brightness 8.08 likes
Typing
Spectral class M3 II / M4 II:
Variable star type SRc 
Astrometry
Radial velocity +49 km / s
parallax approx. 0.67  mas
distance 3,900  ly
1,200  pc
Visual absolute brightness M vis approx. −3 mag
Proper movement 
Rec. Share: (+5.72 ± 2.01)  mas / a
Dec. portion: (−6.75 ± 4.47)  mas / a
Physical Properties
Dimensions 30 to 40  M ☉
radius 1420 ± 120  R ☉
Luminosity

(430000)  L ☉

Effective temperature (3600)  K
Other names
and catalog entries
Cordoba Survey CD −25 ° 4441
Henry Draper Catalog HD 58061 [1]
Hipparcos catalog HIP 35793 [2]
SAO catalog SAO 173591 [3]
Tycho catalog TYC 6541-2525-1 [4]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS J07225830-2546030 [5]

VY Canis Majoris ( VY CMa ) is a red supergiant . This star is one of the largest stars in the Milky Way , the size of which is known or can be estimated.

properties

  • Size comparison between the Sun and VY Canis Majoris

  • Size comparison between VY Canis Majoris (right) and various stars

In 2006 Roberta M. Humphreys calculated the radius of VY CMa to be 1800 to 2100 times the solar radius (R ☉ ).

More recent studies from 2012 indicate a smaller radius of 1420 ± 120 R ☉ and a closer proximity of 1200 (instead of 1500) parsecs (3900  light years , 37 quadrillion km). If the sun were replaced by such a star, it would expand over the orbit of Jupiter .

There are two different opinions on the assignment of VY CMa: Some researchers (such as Roberta M. Humphreys in her work) believe that the star is a very large and very bright red supergiant . Others (according to the study by Massey, Levesque and Plez), however, come to the conclusion that VY CMa is just a normal red supergiant.

The name part "VY" follows the rules for naming variable stars and states that VY Canis Majoris is the 43rd variable star discovered in the constellation of the Big Dog (Canis Majoris) .

In 2007, American astronomers working with Lucy Ziurys discovered hydrogen cyanide , carbon disulfide , sodium chloride and phosphorus-nitrogen compounds in the vicinity of the star during investigations with a 10-meter radio telescope . This surrounding cloud is also the reason why only a fraction of the visible light emanating from the star arrives on earth and VY CMa therefore appears much darker than would be assumed based on its luminosity .

See also

Web links

Commons : VY Canis Majoris  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c Hipparcos catalog (ESA 1997)
  2. ^ A b c E. De Beck, L. Decin, A. De Koter, K. Justtanont, T. Verhoelst, F. Kemper, KM Menten: Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles . II. CO line survey of evolved stars: Derivation of mass-loss rate formulas . In: Astronomy and Astrophysics . 523, 2010, p. A18. arxiv : 1008.1083 . bibcode : 2010A & A ... 523A..18D . doi : 10.1051 / 0004-6361 / 200913771 .
  3. ↑ roughly estimated based on the apparent brightness and distance
  4. ↑ Hipparcos catalog (2007)
  5. ^ M. Wittkowski, PH Hauschildt, B. Arroyo-Torres, JM Marcaide: Fundamental properties and atmospheric structure of the red supergiant VY Canis Majoris based on VLTI / AMBER spectro-interferometry . In: Astronomy & Astrophysics 540, L12 2012, doi : 10.1051 / 0004-6361 / 201219126
  6. ^ VY Canis Majoris: The Astrophysical Basis of Its Luminosity
  7. ↑ Bringing VY Canis Majoris Down to Size: An Improved Determination of Its Effective Temperature
  8. ↑ The dying star as the source of life