HD 95109

Last updated
HD 95109
Carina constellation map.svg
Red circle.svg
Location of U Carinae (circled)
Observation data
Epoch J2000       Equinox J2000
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 mas/yr [3]
Dec.: +2.397 mas/yr [3]
Parallax (π)0.553±0.0226  mas [3]
Distance 6,187±218  ly
(1898±67  pc) [4]
Absolute magnitude  (MV)−5.27 [5]
Details
Mass 7.5 - 11.7 [6]   M☉
Radius 187±5 [4]   R☉
Luminosity 26,642±1,584 [4]   L☉
Surface gravity (log g)1.2 [7]   cgs
Temperature 5,397 [4]  –5,980 [7]   K
Metallicity +0.01 [8]
Age 29 [8]   Myr
Other designations
U  Car, CD −59°3448, HD  95109, HR  4276, HIP  52589
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.

A near-infrared (J band) light curve for U Carinae, adapted from Laney and Stobie (1992) UCarLightCurve.png
A near-infrared (J band) light curve for U Carinae, adapted from Laney and Stobie (1992)

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. 1 2 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. 1 2 3 4 Samus, N. N.; Durlevich, O. V.; 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. 1 2 3 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  4. 1 2 3 4 Gallenne, A.; Mérand, A.; Kervella, P.; Pietrzyński, G.; Gieren, W.; Hocdé, V.; Breuval, L.; Nardetto, N.; Lagadec, E. (May 25, 2021). "Extended envelopes around Galactic Cepheids. V. Multi-wavelength and time-dependent analysis of IR excess". Astronomy & Astrophysics. 651: A113. arXiv: 2105.12197 . Bibcode:2021A&A...651A.113G. doi:10.1051/0004-6361/202140350. ISSN   0004-6361.
  5. ↑ Groenewegen, M. A. T. (2013). "Baade-Wesselink distances to Galactic and Magellanic Cloud Cepheids and the effect of metallicity". Astronomy & Astrophysics. 550: A70. arXiv: 1212.5478 . Bibcode:2013A&A...550A..70G. doi:10.1051/0004-6361/201220446. S2CID   118665355.
  6. ↑ 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. arXiv: astro-ph/0505149 . Bibcode:2005ApJ...629.1021C. doi:10.1086/431641. S2CID   17359646.
  7. 1 2 Romaniello, M.; Primas, F.; Mottini, M.; Pedicelli, S.; Lemasle, B.; Bono, G.; François, P.; Groenewegen, M. A. T.; Laney, C. D. (2008). "The influence of chemical composition on the properties of Cepheid stars. II. The iron content". Astronomy and Astrophysics. 488 (2): 731. arXiv: 0807.1196 . Bibcode:2008A&A...488..731R. doi:10.1051/0004-6361:20065661. S2CID   16955805.
  8. 1 2 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. Bibcode:2013AstL...39..851M. doi:10.1134/S1063773713120050. S2CID   119788977.
  9. ↑ 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.
  10. ↑ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C.
  11. ↑ 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. Bibcode:1918ApJ....48..279S. doi:10.1086/142435.
  12. ↑ Laney, C. D.; Stobie, R. S. (1995). "The radii of Galactic Cepheids". Monthly Notices of the Royal Astronomical Society. 274 (2): 337. Bibcode:1995MNRAS.274..337L. doi: 10.1093/mnras/274.2.337 .
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