Westerlund 1-75

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Westerlund 1-75
Westerlund 1 super star cluster. The location of Wd 1-75 is circled.
Credit: ESO
Observation data
Epoch J2000      Equinox J2000
Constellation Ara
Right ascension 16h 47m 08.92s[1]
Declination −45° 49′ 58.5″[1]
Apparent magnitude (V) 16.7
Characteristics
Evolutionary stage
Red supergiant
Spectral type M1[2] - M4Ia[3]
Apparent magnitude (J) 6.933[4]
Apparent magnitude (H) 4.673[4]
Apparent magnitude (K) 3.28[4]
Distance
4,120+660
−330
[5] pc
Details
Radius722±36[2] R
Luminosity120,000±14,000[2] L
Temperature3,600[6] - 4,000[2] K
Other designations
Westerlund 1 BKS E, 2MASS J16470892-4549585, Gaia DR3 5940199877892579584
Database references
SIMBADdata

Westerlund 1 W75 or Wd 1-75 is a red supergiant (RSG) located in the Westerlund 1 super star cluster. Its radius is calculated to be around 668 solar radii[6] (4.65 × 108 km, 3.10 au). This corresponds to a volume 298 million times bigger than the Sun. If placed at the center of the Solar System, Westerlund 1-75 would engulf the inner limits of the asteroid belt.

Westerlund 1-75 compared to the other 3 RSGs in the Westerlund 1 star cluster.

The star is classified as a luminous cool

supergiant emitting most of its energy in the infrared spectrum.[7] It occupies the upper right corner of the Hertzsprung-Russell diagram. Using the effective temperature of 3,600 K,[6] the bolometric luminosity of 68,000 L[6] and the solar effective temperature of 5,772 K,[8] the radius of Westerlund 1-75 can be calculated using the Stefan-Boltzmann law at 668 R.[a]

Like Westerlund 1-20, Westerlund 1 W26 and Westerlund 1-237, Westerlund 1-75 was observed to be a radio source, however it is weakest along the RSGs in its cluster and remains unresolved at any wavelength.[9]

Westerlund 1-75 is surrounded by extended nebula, although it appears less massive than nebulae around typical red supergiant stars.[10]

See also

Notes

  1. ^

References