Astronomy:HD 95109
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Short description: Star in the constellation Carina
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Carina |
| Right ascension | 10h 57m 48.18690s[1] |
| Declination | −59° 43′ 55.8872″[1] |
| Apparent magnitude (V) | 5.72 - 6.90[2] |
| Characteristics | |
| Evolutionary stage | Yellow supergiant |
| Spectral type | F6-G7 Iab[2] |
| Variable type | δ Cep[2] |
| Astrometry | |
| Proper motion (μ) | RA: −5.963[3] mas/yr Dec.: +2.397[3] mas/yr |
| Parallax (π) | 0.553 ± 0.0226[3] mas |
| Distance | 6,187±218 ly (1898±67 pc) |
| Absolute magnitude (MV) | −5.27[4] |
| Details | |
| Mass | 7.5 - 11.7[5] M☉ |
| Radius | 187±5[6] R☉ |
| Luminosity | 26,642±1,584[6] L☉ |
| Surface gravity (log g) | 1.2[7] cgs |
| Temperature | 5,397[6] – 5,980[7] K |
| Metallicity | +0.01[8] |
| Age | 29[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 95109 (U Carinae) is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude is 6.86.
U Car is a δ Cepheid variable with a period of 38.7681 days. Isaac Roberts discovered that the star's brightness varies in 1891,[10] and it was one of the earliest Cepheids to be discovered. It has also one of the longest periods, and hence is one of the most luminous in the class.[11] There are still only a few Cepheids with longer periods, including RS Puppis, SV Vulpeculae, and the unusual S Vulpeculae.[2]
The brightness variation in U Car is caused by fundamental mode pulsations. The radius and temperature both vary, with the radius changing by 42 R☉ during each cycle.[12] The temperature variation causes the spectral type to vary between F6 and G7.
References
- ↑ 1.0 1.1 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode: 2009yCat....102025S.
- ↑ 3.0 3.1 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.
- ↑ Groenewegen, M. A. T. (2013). "Baade-Wesselink distances to Galactic and Magellanic Cloud Cepheids and the effect of metallicity". Astronomy & Astrophysics 550: A70. doi:10.1051/0004-6361/201220446. Bibcode: 2013A&A...550A..70G.
- ↑ Caputo, F.; Bono, G.; Fiorentino, G.; Marconi, M.; Musella, I. (2005). "Pulsation and Evolutionary Masses of Classical Cepheids. I. Milky Way Variables". The Astrophysical Journal 629 (2): 1021–1033. doi:10.1086/431641. Bibcode: 2005ApJ...629.1021C.
- ↑ 6.0 6.1 6.2 Gallenne, A.; Mérand, A.; Kervella, P.; Pietrzyński, G.; Gieren, W.; Hocdé, V.; Breuval, L.; Nardetto, N. et al. (May 25, 2021). "Extended envelopes around Galactic Cepheids. V. Multi-wavelength and time-dependent analysis of IR excess". Astronomy & Astrophysics 651: A113. doi:10.1051/0004-6361/202140350. ISSN 0004-6361. Bibcode: 2021A&A...651A.113G.
- ↑ 7.0 7.1 Romaniello, M.; Primas, F.; Mottini, M.; Pedicelli, S.; Lemasle, B.; Bono, G.; François, P.; Groenewegen, M. A. T. et al. (2008). "The influence of chemical composition on the properties of Cepheid stars. II. The iron content". Astronomy and Astrophysics 488 (2): 731. doi:10.1051/0004-6361:20065661. Bibcode: 2008A&A...488..731R.
- ↑ 8.0 8.1 Marsakov, V. A.; Koval', V. V.; Kovtyukh, V. V.; Mishenina, T. V. (2013). "Properties of the population of classical Cepheids in the Galaxy". Astronomy Letters 39 (12): 851. doi:10.1134/S1063773713120050. Bibcode: 2013AstL...39..851M.
- ↑ Laney, C. D.; Stobie, R. S. (April 1992). "JHKL Observations of Galactic Cepheids". Astronomy & Astrophysics Supplement Series 93: 93–120. Bibcode: 1992A&AS...93...93L. https://ui.adsabs.harvard.edu/abs/1992A&AS...93...93L. Retrieved 20 November 2021.
- ↑ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory 55: 1–94. Bibcode: 1907AnHar..55....1C. https://articles.adsabs.harvard.edu/pdf/1907AnHar..55....1C. Retrieved 8 January 2025.
- ↑ Shapley, H. (1918). "Studies based on the colors and magnitudes in stellar clusters. VIII. The luminosities and distances of 139 Cepheid variables". Astrophysical Journal 48: 279. doi:10.1086/142435. Bibcode: 1918ApJ....48..279S.
- ↑ Laney, C. D.; Stobie, R. S. (1995). "The radii of Galactic Cepheids". Monthly Notices of the Royal Astronomical Society 274 (2): 337. doi:10.1093/mnras/274.2.337. Bibcode: 1995MNRAS.274..337L.
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