HD 74180

From Wikipedia, the free encyclopedia
This article is about b Velorum. For B Velorum, see HD 70930.
b Velorum
Vela constellation map.svg
Red circle.svg
Location of b Vel (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
Right ascension 08h 40m 37.57017s[1]
Declination −46° 38′ 55.4770″[1]
Apparent magnitude (V) 3.81[2]
Characteristics
Spectral type F0Ia[3]
U−B color index +0.34[2]
B−V color index +0.71[2]
Variable type suspected α Cyg[4]
Astrometry
Radial velocity (Rv)−25.3[5] km/s
Proper motion (μ) RA: −6.055[1] mas/yr
Dec.: 4.66[1] mas/yr
Parallax (π)0.68 ± 0.16[1] mas
Distance990[6] pc
Absolute magnitude (MV)−6.50[6]
Details
Mass12.63[6] M☉
Luminosity38,000[6] L☉
Surface gravity (log g)1.38[6] cgs
Temperature5,750[6] K
Metallicity [Fe/H]0.56[7] dex
Rotational velocity (v sin i)21.7[8] km/s
Other designations
b Velorum, HR 6513, HD 74180, CD−46°4438, FK5 1226, HIP 42570, SAO 220265
Database references
SIMBADdata

HD 74180 is a binary star in the constellation Vela. It is approximately 3,200 light years from Earth. The primary component is a yellow-white F-type supergiant with a mean apparent magnitude of +3.81, with a 10th magnitude companion 37.5 arcseconds distant.[citation needed]

b Velorum has been classified as a suspected α Cygni variable star which varies by only 0.06 magnitude. There are possible periods near 53, 80, and 160 days, but the variation is largely irregular.[4] It lies less than a degree from the small open cluster , but is not a member.[6]

Several studies have considered b Velorum to be a highly luminous supergiant or hypergiant with an early F spectral type, for example F2 Ia+,[4] F0 Ia,[9] and F4 I.[10] There were corresponding luminosity estimates of several hundred thousand L☉. A 2015 study used the Barbier-Chalonge-Divan (BCD) system to derive a luminosity of 38,000 L☉ and a cooler less luminous F8 Ib spectral type.[6]

References[]

  1. ^ a b c d e Van Leeuwen, Floor (2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ Houk, Nancy (1978). "Michigan catalogue of two-dimensional spectral types for the HD stars". Ann Arbor: Dept. Of Astronomy, University of Michigan. 2. Bibcode:1978MSS...C02....0H.
  4. ^ a b c Van Leeuwen, F.; Van Genderen, A. M.; Zegelaar, I. (1998). "Hipparcos photometry of 24 variable massive stars (α Cygni variables)". Astronomy and Astrophysics Supplement Series. 128: 117–129. Bibcode:1998A&AS..128..117V. doi:10.1051/aas:1998129.
  5. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
  6. ^ a b c d e f g h Aidelman, Y.; Cidale, L. S.; Zorec, J.; Panei, J. A. (2015). "Open clusters. II. Fundamental parameters of B stars in Collinder 223, Hogg 16, NGC 2645, NGC 3114, and NGC 6025". Astronomy & Astrophysics. 577: A45. Bibcode:2015A&A...577A..45A. doi:10.1051/0004-6361/201425085.
  7. ^ Luck, R. Earle (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal. 147 (6): 137. Bibcode:2014AJ....147..137L. doi:10.1088/0004-6256/147/6/137.
  8. ^ Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID 53666672
  9. ^ Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal. 38: 309. Bibcode:1978ApJS...38..309H. doi:10.1086/190559.
  10. ^ Mersch, G.; Heck, A. (1980). "Prediction of spectral classification from photometric observations - Application of the UVBY beta photometry and the MK spectra classification. II - General case". Astronomy and Astrophysics. 85: 93. Bibcode:1980A&A....85...93M.
Retrieved from ""