69 Herculis
{{Short description|Star in the constellation Hercules}}
{{about-distinguish2|e Herculis|ε (epsilon) Herculis}}
{{Starbox begin}}
{{Starbox observe
| epoch = J2000
| constell = Hercules
| dec = {{DEC|+37|17|29.3995}}
| appmag_v = {{nowrap|4.63 (4.66 + 8.68)}}
}}
{{Starbox character
| type = main sequence
| u-b =
| variable =
}}
{{Starbox astrometry
| radial_v = {{Val|−9.90|1.78}}
| parallax = 18.59
| p_error = 0.33
}}
{{Starbox detail
| source =
| component1 = 69 Her A
}}
{{Starbox catalog
| names={{odlist | B=e Her | F=69 Her | BD=+37°2864 | HD=156729 | HIP=84606 | HR=6436 | SAO=65921 }}
}}
{{Starbox reference
| Simbad=69+Her
}}
{{Starbox end}}
69 Herculis is a binary star system in the northern constellation Hercules. It has the Bayer designation e Herculis, while 69 Herculis is the Flamsteed designation. This object is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 4.63. The distance to this system can be estimated from parallax measurements, which yields a range of 175 light years. It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.
The magnitude 4.66 primary, designated component A, is an A-type main-sequence star with a stellar classification of A2V. It is 155 million years old with 2.12 times the mass of the Sun. The star is spinning with a projected rotational velocity of 155 km/s, which is creating an equatorial bulge that is 5% larger than the star's polar radius. It is about 2.2 times the size of the Sun and is radiating 37 times the Sun's luminosity from its photosphere at an effective temperature of 9,141 K.
The secondary, component B, is magnitude 8.68 star with an angular separation of {{Val|0.840|ul=arcsecond}} from the primary, as of 2008. X-ray emission has been detected from this system. As A-type stars are not expected to be X-ray sources, this emission is most likely coming from the companion.
References
{{reflist|refs=
{{cite simbad | title=69 Her | access-date=2019-06-15 }}
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| arxiv=1208.3048 | s2cid=59451347 | postscript=. }}
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| arxiv=0708.1752 | bibcode=2007A&A...474..653V
| doi=10.1051/0004-6361:20078357 | s2cid=18759600 }}
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| bibcode=2012AstL...38..331A | arxiv=1108.4971
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| bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}
| title=Automated spectroscopic abundances of A and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE
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| journal=The Astrophysical Journal
| volume=804 | issue=2 | pages=146 | year=2015
| bibcode=2015ApJ...804..146D | arxiv=1501.03154
| doi=10.1088/0004-637X/804/2/146 | s2cid=33401607 | postscript=. }}
| last1=van Belle | first1=Gerard T.
| title=Interferometric observations of rapidly rotating stars
| journal=The Astronomy and Astrophysics Review
| volume=20 | issue=1 | page=51 | date=March 2012
| doi=10.1007/s00159-012-0051-2 | bibcode=2012A&ARv..20...51V
| arxiv=1204.2572 | s2cid=119273474
| postscript=. }}
| title=X-ray emission from A-type stars
| last1=Schröder | first1=C. | last2=Schmitt | first2=J. H. M. M.
| journal=Astronomy and Astrophysics | postscript=.
| volume=475 | issue=2 | date=November 2007 | pages=677−684
| doi=10.1051/0004-6361:20077429 | bibcode=2007A&A...475..677S | doi-access=free }}
| display-authors=1 | last1=Pasinetti Fracassini | first1=L. E.
| last2=Pastori | first2=L. | last3=Covino | first3=S. | last4=Pozzi | first4=A.
| title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)
| edition=Third | journal=Astronomy and Astrophysics
| volume=367 | issue=2 | pages=521–524 | date=February 2001
| doi=10.1051/0004-6361:20000451 | postscript=.
| bibcode=2001A&A...367..521P | arxiv=astro-ph/0012289 | s2cid=425754 }}
| last1=Cowley | first1=A. | last2=Cowley | first2=C.
| last3=Jaschek | first3=M. | last4=Jaschek | first4=C.
| title=A study of the bright A stars. I. A catalogue of spectral classifications
| display-authors=1 | journal=Astronomical Journal
| volume=74 | pages=375–406 | date=April 1969
| doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}
}}
{{Stars of Hercules}}
{{DEFAULTSORT:69 Herculis}}
Category:A-type main-sequence stars
Category:Hercules (constellation)