Trumpler 27-1 is a red supergiant star that is a member of the massive, possible open cluster Trumpler-27, where a blue giant star, a yellow supergiant star , and two Wolf–Rayet stars are also located.

Trumpler 27-1

The Trumpler 27 open cluster. Trumpler 27-1 is the brightest and reddest star in the image.
Observation data Epoch J2000      Equinox J2000
Constellation	Scorpius
Right ascension	17h 36m 10.1189s[1]
Declination	−33° 29′ 40.620″[1]
Apparent magnitude (V)	8.79[2]
Characteristics
Evolutionary stage	Red supergiant
Spectral type	M0Ia[2]
Astrometry
Radial velocity (Rv)	−16.84 ± 0.82[1] km/s
Proper motion (μ)	RA: 0.223[1] mas/yr Dec.: −1.179[1] mas/yr
Parallax (π)	0.4020 ± 0.0770 mas[1]
Distance	approx. 8,000 ly (approx. 2,500 pc)
Details
Mass	5.86[3] M☉
Radius	1,073[4] R☉
Luminosity	215,000 – 261,000[4] L☉
Surface gravity (log g)	-0.24[3] cgs
Temperature	3,222[3] – 3,790[4] K
Metallicity [Fe/H]	+0.15[3] dex
Other designations
CD−33 12241, CPD−33 4468, TYC 7380-627-1[2]
Database references
SIMBAD	data

Observation history

Trumpler 27-1 was discovered and catalogued when the open cluster (not confirmed then) was first identified in the late 20th century.^{[citation needed]} It has since remained largely unobserved, being featured in the Gaia Catalogue and other pieces of literature.[5]

Physical properties

Trumpler 27-1 is among the largest stars known, with a radius of over 1,000 solar radii, one estimate giving 1,073 R_☉ and another giving a size of over 1,300 solar radii.[5] This star's spectral type is M0Ia,[4] meaning it possesses a cool temperature of below 3,800 K. So far, Trumpler 27-1 is the only identified red supergiant in the open cluster Trumpler 27.^{[citation needed]}

Location

Trumpler 27–1, and the open cluster in which it is located, is in the constellation of Scorpius.

See also

• Westerlund 1-26
• RSGC1

References