參旗六

參旗六，即獵戶座π3（Pi3 Orionis、π3 Ori、π3 Orionis），是一顆位於獵戶座的恆星，西方傳統名稱是 Tabit，佛蘭斯蒂德命名法將該恆星命名為獵戶座1（1 Orionis）。它的視星等是肉眼可見的3.16。參旗六是獵戶座中代表獅皮（或盾牌）的恆星中最亮的。根據視差量測，它和地球的距離是26.32光年（8.07秒差距）。雖然在參旗六旁至今並未發現太陽系外行星，該恆星仍被部分天文學家[谁？]認為它周圍的特定位置允許體積和地球相當的行星存在。 參旗六是一顆光譜類型 F6 V 的主序星，自1943年起它的光譜就是該型恆星的標準光譜。它的質量是太陽的124%，半徑比太陽大32%，並且光度幾乎是太陽的3倍。它的外層氣體有效溫度是6,516 K，因此屬於黃白色的F-型主序星。參旗六很可能是單一恆星，天球上與它接近的另一顆恆星是光學雙星。 雖然參旗六的徑向速度會以73.26日的週期變化，引起變化的原因較可能是恆星本身的活動，而非距離它相當近的行星引起。目前並未偵測到參旗六周圍有次恆星伴星存在，而麦克唐纳天文台的一個團隊則認為在質量0.84到46.7倍木星質量，距離母恆星0.05到5.2天文單位的限制條件下會有一或多顆行星存在。此外，到目前為止即使有類似地球的行星存在，也並未觀測到其重力對母恆星運動造成擾動。 獵戶座π van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357.  Johnson, H. L.; Morgan, W. W., Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas, Astrophysical Journal, 1953, 117: 313–352, Bibcode:1953ApJ...117..313J, doi:10.1086/145697.  Kukarkin, B. V.; et al., Nachrichtenblatt der Vereinigung der Sternfreunde e.V. (Catalogue of suspected variable stars), Moscow: Academy of Sciences USSR Shternberg, 1981, Bibcode:1981NVS...C......0K.  引文使用过时参数coauthors (帮助) Evans, D. S., The Revision of the General Catalogue of Radial Velocities, Batten, Alan Henry; Heard, John Frederick (编), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, June 20–24, 1966, Bibcode:1967IAUS...30...57E.  Holmberg, J.; Nordström, B.; Andersen, J., The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics, Astronomy and Astrophysics, Supplement Series, July 2009, 501 (3): 941−947, Bibcode:2009A&A...501..941H, arXiv:0811.3982 , doi:10.1051/0004-6361/200811191.  Note: see VizieR catalogue V/130 （页面存档备份，存于互联网档案馆）. Takeda, G.; et al., Stellar parameters of nearby cool stars. II. Physical properties of ~1000 cool stars from the SPOCS catalog, Astrophysical Journal Supplement Series, 2007, 168: 297–318, Bibcode:2008yCat..21680297T  引文使用过时参数coauthors (帮助) Note: see VizieR catalogue J/ApJS/168/297 （页面存档备份，存于互联网档案馆）. Boyajian, Tabetha S.; et al, Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars, The Astrophysical Journal, February 2012, 746 (1): 101, Bibcode:2012ApJ...746..101B, arXiv:1112.3316 , doi:10.1088/0004-637X/746/1/101.  See Table 10. Kuroczkin, D.; Wiszniewski, A., The problem of iron abundance in the SMR stars., Acta Astronomica, 1997, 27: 145–150, Bibcode:1977AcA....27..145K.  Bernacca, P. L.; Perinotto, M., A catalogue of stellar rotational velocities, Contributi Osservatorio Astronomico di Padova in Asiago, 1970, 239 (1), Bibcode:1970CoAsi.239....1B.  1 Ori -- Variable Star, SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), [2011-01-07], （原始内容存档于2016-03-12）  Moore, Patrick; Rees, Robin, Patrick Moore's Data Book of Astronomy 2nd, Cambridge University Press: 460, 2011 [2012-10-15], ISBN 0521899354, （原始内容存档于2020-09-10）  Garrison, R. F., Anchor Points for the MK System of Spectral Classification, Bulletin of the American Astronomical Society, December 1993, 25: 1319 [2012-02-04], Bibcode:1993AAS...183.1710G, （原始内容存档于2019-06-25）  Eggleton, P. P.; Tokovinin, A. A., A catalogue of multiplicity among bright stellar systems, Monthly Notices of the Royal Astronomical Society, September 2008, 389 (2): 869–879, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878 , doi:10.1111/j.1365-2966.2008.13596.x.  Wittenmyer, Robert A.; et al., Detection Limits from the McDonald Observatory Planet Search Program, The Astronomical Journal, July 2006, 132 (1): 177–188, Bibcode:2006AJ....132..177W, arXiv:astro-ph/0604171 , doi:10.1086/504942.  引文使用过时参数coauthors (帮助) Pi3 Orionis 2?. SolStation. [2008-07-11]. （原始内容存档于2008-07-19）.