V810 Centauri

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V810 Cen A/B
Observation data
Epoch J2000      Equinox J2000
Constellation Centaurus
Right ascension 11h 43m 31.193s[1]
Declination –62° 29′ 21.82″[1]
Apparent magnitude (V) 5.021var[2]
Characteristics
Spectral type F8Ia / B0III[2]
U−B color index 1.762[2]
B−V color index 0.014[2]
Variable type Semi-regular
Astrometry
Radial velocity (Rv) 16.44[3] km/s
Proper motion (μ) RA: –5.74 ± 0.21[1] mas/yr
Dec.: 1.30 ± 0.17[1] mas/yr
Parallax (π) 0.46 ± 0.22[1] mas
Distance 3,300 - 3,500[2] pc
Absolute magnitude (MV) -8.4/-5.1[2]
Details
Mass 20/25[2] M
Radius 420/14[2] R
Luminosity 200,000/125,000[2] L
Surface gravity (log g) 0.7/3.5[2] cgs
Temperature 6,010/29,000[2] K
Age 6-10 million[citation needed] years
Other designations
HIP 57175, SAO 251555, CD-61° 3163, HR 4511, CPD-61° 2559, HD 101947.
Database references
SIMBAD data

V810 Centauri is a double star consisting of a yellow supergiant primary (V810 Cen A) and blue giant secondary (V810 Cen B). It is a small amplitude variable star, entirely due to the supergiant primary which is visually over three magnitudes brighter than the secondary.[4]

V810 Cen A shows semi-regular variations with several component periods. The dominant mode is around 156 days and corresponds to Cepheid fundamental mode radial pulsation. Without the other pulsation modes it would be considered a Classical Cepheid variable. Other pulsation modes have been detected at 89 to 234 days, with the strongest being a possible non-radial p-mode at 107 days and a possible non-radial g-mode at 185 days. [2]

The blue giant secondary has a similar mass and luminosity to the supergiant primary, but is visually much fainter. The primary is expected to have lost around 5 M since it was on the main sequence, and has expanded and cooled so it lies at the blue edge of the Cepheid instability strip. It is expected to get no cooler and may perform a blue loop while slowly increasing in luminosity.[2]

V810 Cen was once thought to be a member of the Stock 14 open cluster at 2.6 kpc,[5] but now appears to be more distant. The distance derived from spectrophotometric study is larger than the mean Hipparcos parallax value but within the margin of error.

References[edit]

  1. ^ a b c d e 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.  edit
  2. ^ a b c d e f g h i j k l m Kienzle, F.; Burki, G.; Burnet, M.; Meynet, G. (1998). "The pulsating yellow supergiant V810 Centauri". Astronomy and Astrophysics 337: 779. Bibcode:1998A&A...337..779K. 
  3. ^ Mermilliod, J. C.; Mayor, M.; Udry, S. (2008). "Red giants in open clusters. XIV. Mean radial velocities for 1309 stars and 166 open clusters". Astronomy and Astrophysics 485: 303. Bibcode:2008A&A...485..303M. doi:10.1051/0004-6361:200809664. 
  4. ^ Eichendorf, W.; Lub, J.; Pakull, M.; Heck, A.; Isserstedt, J.; Reipurth, B.; Van Genderen, A. M. (1981). "On the nature of the 125-day Cepheid V 810 CEN /equals HR 4511/ - IUE spectra". Astronomy and Astrophysics 93: L5. Bibcode:1981A&A....93L...5E. 
  5. ^ Turner, D. G. (1982). "New UBV photometry for the open cluster Stock 14 and its Cepheid-like variable V810 Centauri /= HR 4511/". Astronomical Society of the Pacific 94: 655. Bibcode:1982PASP...94..655T. doi:10.1086/131039. 

Coordinates: Sky map 14h 39m 36.4951s, −60° 50′ 02.308″