Star in the constellation Hercules
Xi Herculis is a solitary[ 11] Hercules . The star is visible to the naked eye with an apparent visual magnitude of 3.70.[ 2] parallax shift of 23.85 mas as seen from Earth, it is located 137 light years from the Sun .[ 1] extinction factor of 0.05 due to interstellar dust . It is a suspected member of the Sirius stream of co-moving stars.[ 12]
A light curve for Xi Herculis, plotted from Hipparcos data[ 13] This is an evolved G-type giant star with a stellar classification of G8 III.[ 3] red clump star, which means it is on the horizontal branch and generating energy through the thermonuclear fusion of hydrogen at its core. The star is emitting X-rays with a luminosity of × 1030 erg s−1 [ 9] [ 6] mass of the Sun but, at the age of two and a half billion years,[ 6] Sun's radius . The star is radiating 57 times the solar luminosity from its photosphere at an effective temperature of 5,032 K.[ 7]
Xi Herculis was discovered to be a variable star when the Hipparcos [ 14] semiregular variable star , oscillating in brightness by 3 hundredths of a magnitude, over a period of 120.8 days.[ 15]
Chinese name
In R.H.Allen's book Star Names: Their Lore and Meaning , this star, together with ν Her and 99 Her (b Herculis) represent the state of Zhongshan (or Chung Shan' "the Middle Mountain"),[ 16] ο Her .[ 17]
One third of a degree to the north-northwest of Xi Herculis is the location of a telescopic asterism in the shape of a teapot. This teapot (Markov 1) could be seen as a somewhat twisted small equivalent of the large and easy to recognize teapot asterism in the constellation Sagittarius .
References
^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties" . Astronomy and Astrophysics . 674 : A1. arXiv :2208.00211 Bibcode :2023A&A...674A...1G . doi :10.1051/0004-6361/202243940 S2CID 244398875 . Gaia DR3 record for this source at VizieR .^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data , SIMBAD , Bibcode :1986EgUBV........0M . ^ a b Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics , 11 (1): 29, Bibcode :1973ARA&A..11...29M , doi :10.1146/annurev.aa.11.090173.000333 . ^ a b Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal , 135 (1): 209– 231, Bibcode :2008AJ....135..209M , doi :10.1088/0004-6256/135/1/209 S2CID 121883397 . ^ Böhm-Vitense, Erika; et al. (December 2000), "Ultraviolet Emission Lines in BA and Non-BA Giants", The Astrophysical Journal , 545 (2): 992– 999, Bibcode :2000ApJ...545..992B , doi :10.1086/317850 ^ a b c d Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal , 150 (3): 23, arXiv :1507.01466 Bibcode :2015AJ....150...88L , doi :10.1088/0004-6256/150/3/88 , S2CID 118505114 , 88. ^ a b c d Baines, Ellyn K.; Thomas Armstrong, J.; Clark, James H.; Gorney, Jim; Hutter, Donald J.; Jorgensen, Anders M.; Kyte, Casey; Mozurkewich, David; Nisley, Ishara; Sanborn, Jason; Schmitt, Henrique R.; Van Belle, Gerard T. (2021). "Angular Diameters and Fundamental Parameters of Forty-four Stars from the Navy Precision Optical Interferometer" . The Astronomical Journal . 162 (5): 198. arXiv :2211.09030 Bibcode :2021AJ....162..198B . doi :10.3847/1538-3881/ac2431 ^ a b Prugniel, Ph.; et al. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics , 531 : A165, arXiv :1104.4952 Bibcode :2011A&A...531A.165P , doi :10.1051/0004-6361/201116769 , S2CID 54940439 . ^ a b Gondoin, P. (December 2005), "The relation between X-ray activity and rotation in intermediate-mass G giants", Astronomy and Astrophysics , 444 (2): 531– 538, Bibcode :2005A&A...444..531G , doi :10.1051/0004-6361:20053567 ^ "ksi Her" . SIMBAD Centre de données astronomiques de Strasbourg . Retrieved 2017-04-08 .{{cite web }}: CS1 maint: postscript (link )^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869– 879, arXiv :0806.2878 Bibcode :2008MNRAS.389..869E , doi :10.1111/j.1365-2966.2008.13596.x S2CID 14878976 . ^ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics , 430 (1): 165– 186, arXiv :astro-ph/0409579 Bibcode :2005A&A...430..165F , doi :10.1051/0004-6361:20041272 , S2CID 17804304 . ^ "/ftp/cats/more/HIP/cdroms/cats" . Centre de Données astronomiques de Strasbourg . Strasbourg astronomical Data Center. Retrieved 15 October 2022 .^ Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (January 1999). "The 74th Special Name-list of Variable Stars" (PDF) . Information Bulletin on Variable Stars . 4659 . Bibcode :1999IBVS.4659....1K . Retrieved 23 December 2024 . ^ "ksi Her" . The International Variable Star Index . AAVSO. Retrieved 3 December 2022 .^ Allen, R. H. (1963), Star Names, Their Lore and Meaning , retrieved 2017-04-11 . ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 6 日 Archived 2021-05-15 at the Wayback Machine
