V1027 Cygni

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V1027 Cygni
V1027CygLightCurve.png
A visual band light curve for V1027 Cygni, adapted from Arkhipova et al. (2016) [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Cygnus
Right ascension 20h 02m 27.376s [2]
Declination +30° 04 25.49 [2]
Apparent magnitude  (V)8.6-9.6 [1]
Characteristics
Evolutionary stage Yellow supergiant
Spectral type G7Ia [3]
U−B color index +1.9 +2.8 [1]
B−V color index +2.1 +2.5 [1]
Variable type L [4]
Astrometry
Proper motion (μ)RA: −2.936 [2]   mas/yr
Dec.: −5.55 [2]   mas/yr
Parallax (π)0.2390 ± 0.0178  mas [2]
Distance 14,000 ± 1,000  ly
(4,200 ± 300  pc)
Absolute magnitude  (MV)−7.956 [3]
Details
Radius 559 [3] [lower-alpha 1]   R
Luminosity 176,200 [3]   L
Surface gravity (log g)−0.81 [5]   cgs
Temperature 5,000 [3]   K
Other designations
HD 333385, TYC 2670-4475-1, 2MASS  J20022738+3004252
Database references
SIMBAD data

V1027 Cygni is a luminous yellow supergiant star located in the constellation of Cygnus, about 14,000 light years away. For a time, it was thought that it could be a low-mass post-AGB star, however recent parallax measurements published in Gaia DR3 have shown this to likely not be the case, and instead it is likely a massive yellow supergiant star. [3]

Contents

Properties

V1027 Cygni has a surface temperature about 5,000 K, which has been found in many studies. However, studies before Gaia DR3 generally used a distance around 1,280  pc , which led to low luminosity estimates, hence a tentative post-AGB star status. [1] Recent Gaia DR3 data shows that V1027 Cygni is likely much further away, over 4,000 pc away, which implies a much higher luminosity (about 176,000  L) which would place it firmly outside the post-AGB star luminosity range and in that of the more massive, younger yellow supergiants. [3] Spectral indicators of luminosity also suggest a supergiant status. [1]

Assuming a temperature of 5,000 K and a luminosity of about 176,200 L☉ for V1027 Cygni leads to a size of about 560 times that of the Sun. [lower-alpha 1]

Variability

When V1027 Cygni was first noticed as a variable star, it was thought to be an irregular variable, dimming and brightening erratically with no discernible period. However, in 2009, a small-amplitude period of 237 days was observed in long-term photometry of the star. [1]

Notes

  1. 1 2 Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772  K:

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References

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