| 词条 | 7 Cancri |
| 释义 |
|constell= Cancer |epoch = J2000 |ra= {{RA|08|03|50.47704}}[1] |dec= {{DEC|+22|04|14.9019}}[1] |appmag_v = 6.84[3] }}{{Starbox character |type = Giant star |class = gK3[3] }}{{Starbox astrometry |radial_v = 2.20[5] |prop_mo_ra = {{val|-40.839}}[5] |prop_mo_dec = {{val|5.213}}[5] |parallax = 5.8359 |p_error = 0.0456 |parallax_footnote = [5] |absmag_v = +0.32[9] }}{{Starbox detail |mass = |temperature = 4,757[5] |luminosity = 65[5] |radius = 12[5] |age_myr = }}{{Starbox catalog |names={{odlist|B=|BD=+22°1845|FK5=|HD=66347|HIP=39447|HR=|SAO=79903}} }}{{Starbox reference |Simbad=7+Cancri }}{{Starbox end}} 7 Cancri (7 Cnc) is a giant star in the constellation Cancer. Its apparent magnitude is 6.84 and it is about {{val|559|ul=ly}} away. The annual parallax of 7 Cancri determined from the Hipparcos satellite mission is {{val|488|0.56|ul=mas}}, giving a distance of {{val|202|ul=pc}} with an 11.5% margin of error.[9] The more recent and more accurate Gaia Data Release 2 contains a parallax of {{val|5.8359|0.0456|u=mas}}, resulting in a closer distance of {{val|171|1|u=pc}}. Based on the Gaia distance, 7 Cancri has a bolometric luminosity 65 times that of the sun. Its temperature, based on its colour, is calculated to be {{val|5,757|fmt=commas|ul=K}} and the resulting radius is {{solar radius|12|link=y}}.[5] 7 Cancri is a cool giant star. It has evolved away from the main sequence after exhausting its core hydrogen and expanded so that it is larger and more luminous than the sun, although cooler. It is one of 220 Flamsteed stars that are too faint to have been included in the Bright Star Catalogue. References1. ^1 2 {{cite journal|bibcode=1986PASP...98..423E|title=Hyades and Sirius supercluster members brighter than magnitude (V) 7.1. II - Right ascension six to twelve hours|journal=Astronomical Society of the Pacific|volume=98|pages=423|author1=Eggen|first1=O. J.|year=1986|doi=10.1086/131772}} [1][2][3][4]2. ^1 2 {{cite journal|bibcode= 2007A&A...474..653V |title= Validation of the new Hipparcos reduction |journal= Astronomy and Astrophysics |volume= 474 |issue= 2 |pages= 653–664 |author1= Van Leeuwen |first1= F. |year= 2007 |doi= 10.1051/0004-6361:20078357 |arxiv = 0708.1752 }} 3. ^1 2 3 4 5 6 7 8 {{cite DR2|680043788548399360}} 4. ^1 2 {{cite journal | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | title=XHIP: An extended hipparcos compilation | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | last1=Anderson | first1=E. | last2=Francis | first2=Ch. }} Vizier catalog entry }}{{Stars of Cancer}} 6 : Cancer (constellation)|K-type giants|Flamsteed objects|Henry Draper Catalogue objects|Hipparcos objects|Durchmusterung objects |
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