Astronomy:V1027 Cygni
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[2] mas |
| Distance | 14,000 ± 1,000 ly (4,200 ± 300 pc) |
| Absolute magnitude (MV) | −7.956[3] |
| Details | |
| Radius | 474[5] R☉ |
| Luminosity | 176,200[3] L☉ |
| Surface gravity (log g) | −0.81[6] 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]
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] In the TESS Input Catalog (TIC) from 2019 the star's radius was calculated to be 474 R☉.[5]
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
- ↑ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
- [math]\displaystyle{ \sqrt{(5772/5000)^4 * 176,197.605} = 559.387\ R\odot }[/math]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Arkhipova, V. P.; Taranova, O. G.; Ikonnikova, N. P.; Esipov, V. F.; Komissarova, G. V.; Shenavrin, V. I.; Burlak, M. A. (2016-11-01). "Photometric and spectroscopic study of the supergiant with an infrared excess V1027 Cygni.". Astronomy Letters 42 (11): 756–773. doi:10.1134/S1063773716100017. ISSN 1063-7737. Bibcode: 2016AstL...42..756A.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Parthasarathy, M.; Kounkel, Marina; Stassun, Keivan G. (2022-10-01). "Evolutionary Status of Selected Post-AGB Stars Based on Gaia DR3". Research Notes of the American Astronomical Society 6 (10): 210. doi:10.3847/2515-5172/ac99dd. ISSN 2515-5172. Bibcode: 2022RNAAS...6..210P.
- ↑ Samus', N. N et al. (2017). "General catalogue of variable stars". Astronomy Reports. GCVS 5.1 61 (1): 80. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ 5.0 5.1 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256. Bibcode: 2019AJ....158..138S.
- ↑ Fouesneau, M.; Andrae, R.; Dharmawardena, T.; Rybizki, J.; Bailer-Jones, C. A. L.; Demleitner, M. (2022). "Astrophysical parameters from Gaia DR2, 2MASS, and AllWISE". Astronomy and Astrophysics 662: A125. doi:10.1051/0004-6361/202141828. Bibcode: 2022A&A...662A.125F.
 |  |
