| 词条 | HD 74180 |
| 释义 |
| name=b Velorum }}{{Starbox image | image={{Location mark |image=Vela constellation map.svg |float=center |alt= |label= |position=right |width=280 |mark=Red circle.svg |mark_width=12 |mark_link=b Velorum |x=760|y=431 }} |caption=Location of b Vel (circled) }}{{Starbox observe | epoch=J2000 | ra={{RA|08|40|37.57017}}[1] | dec={{DEC|−46|38|55.4770}}[1] | appmag_v=3.81[2] | constell=Ara }}{{Starbox character | class=F8Ib[4] | r-i = | v-r = | b-v = +0.71[2] | u-b = +0.34[2] | variable=suspected α Cyg[3] }}{{Starbox astrometry | radial_v=−25.3[4] | prop_mo_ra=−6.055[1] | prop_mo_dec=4.66[1] | parallax=0.68 | p_error=0.16 | parallax_footnote=[1] | dist_pc=990[4] | absmag_v=−6.50[5] }}{{Starbox detail | mass=12.63[5] | radius= | luminosity=38,000[5] | temperature=5,750[5] | metal_fe=0.56[6] | gravity=1.38[5] | rotational_velocity=21.7[7] | age= }}{{Starbox catalog | names=b Velorum, HR 6513, HD 74180, CD−46°4438, FK5 1226, HIP 42570, SAO 220265 }}{{Starbox reference | Simbad=HD+158476 }}{{Starbox end}} 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. 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.[3] Several studies have considered b Velorum to be a highly luminous supergiant or hypergiant with an early F spectral type, for example F2 Ia+,[3] F0 Ia,[8] and F4 I.[9] There were corresponding luminosity estimates of {{solar luminosity|several hundred thousand|link=y}}. A 2015 study used the Barbier-Chalonge-Divan (BCD) system to derive a luminosity of {{solar luminosity|38,000}} and a cooler less luminous F8 Ib spectral type.[5] References1. ^1 2 3 4 {{cite journal|bibcode=2007A&A...474..653V|title=Validation of the new Hipparcos reduction|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653|author1=Van Leeuwen|first1=F.|year=2007|doi=10.1051/0004-6361:20078357|arxiv = 0708.1752 }} {{Stars of Vela}}2. ^1 2 {{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|author1=Ducati|first1=J. R.|year=2002}} 3. ^1 2 {{cite journal|doi=10.1051/aas:1998129 |title=Hipparcos photometry of 24 variable massive stars (α Cygni variables) |journal=Astronomy and Astrophysics Supplement Series |volume=128 |pages=117 |year=1998 |last1=Van Leeuwen |first1=F. |last2=Van Genderen |first2=A. M. |last3=Zegelaar |first3=I. |bibcode=1998A&AS..128..117V }} 4. ^{{cite journal|bibcode=1953GCRV..C......0W|title=General catalogue of stellar radial velocities|journal=Washington|author1=Wilson|first1=Ralph Elmer|year=1953}} 5. ^1 2 3 4 5 6 7 {{cite journal|bibcode=2015A&A...577A..45A|title=Open clusters. II. Fundamental parameters of B stars in Collinder 223, Hogg 16, NGC 2645, NGC 3114, and NGC 6025|journal=Astronomy & Astrophysics|volume=577|pages=A45|author1=Aidelman|first1=Y.|last2=Cidale|first2=L. S.|last3=Zorec|first3=J.|last4=Panei|first4=J. A.|year=2015|doi=10.1051/0004-6361/201425085}} 6. ^{{cite journal|bibcode= 2014AJ....147..137L|title= Parameters and Abundances in Luminous Stars|journal= The Astronomical Journal|volume= 147|issue= 6|pages= 137|author1= Luck|first1= R. Earle|year= 2014|doi= 10.1088/0004-6256/147/6/137}} 7. ^{{cite journal|bibcode= 2012A&A...542A.116A|title= New measurements of rotation and differential rotation in A-F stars: Are there two populations of differentially rotating stars?|journal= Astronomy & Astrophysics|volume= 542|pages= A116|author1= Ammler-von Eiff|first1= M.|last2= Reiners|first2= A.|year= 2012|doi= 10.1051/0004-6361/201118724|arxiv = 1204.2459 }} 8. ^{{cite journal|bibcode=1978ApJS...38..309H|title=Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way|journal=Astrophysical Journal|volume=38|pages=309|author1=Humphreys|first1=R. M.|year=1978|doi=10.1086/190559}} 9. ^{{cite journal|bibcode=1980A&A....85...93M|title=Prediction of spectral classification from photometric observations - Application of the UVBY beta photometry and the MK spectra classification. II - General case|journal=Astronomy and Astrophysics|volume=85|pages=93|author1=Mersch|first1=G.|last2=Heck|first2=A.|year=1980}} 9 : Bayer objects|Henry Draper Catalogue objects|Vela (constellation)|Binary stars|Alpha Cygni variables|F-type supergiants|Durchmusterung objects|Hipparcos objects|HR objects |
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