From Wikipedia, the free encyclopedia
Single star in the constellation Ophiuchus
Phi Ophiuchi , a name
Latinized from φ Ophiuchi, is a single
[9]
star in the
equatorial
constellation of
Ophiuchus .
[8] It has a yellow hue and is faintly visible to the naked eye with an
apparent visual magnitude of 4.27.
[2] The star is located at a distance of approximately 244
light-years from the
Sun based on
parallax ,
[1] but it is drifting closer with a
radial velocity of −33.5 km/s.
[4]
The
stellar classification of Phi Opiuchi is G8+IIIa,
[3] an
evolved
giant star that has exhausted the supply of hydrogen at its
core . In 2000, D. R. Alves identified it as a
red clump giant on the
horizontal branch that is generating energy by core
helium fusion .
[10] However, S. Reffert and associates in 2015 instead placed it on the
red-giant branch .
[6] A 2018 study by S. Stock and associates used
Bayesian estimates to arrive at a 94% chance the star is on the horizontal branch.
[11]
The star is around 360
[12]
million years old with an estimated 3.16 times the
mass of the Sun and 13.4 times the
Sun's radius . It is radiating 112 times the
luminosity of the Sun from its enlarged
photosphere at an
effective temperature of 5,131 K.
[6]
It has two visual companions, component B, at magnitude 12.9 and separation 41.3", and component C, at magnitude 10.8 and separation 119.8".
[13]
References
^
a
b
c
d
e
f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics . 474 (2): 653–664.
arXiv :
0708.1752 .
Bibcode :
2007A&A...474..653V .
doi :
10.1051/0004-6361:20078357 .
S2CID
18759600 .
Vizier catalog entry
^
a
b
c
d Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues . 2237 .
Bibcode :
2002yCat.2237....0D .
^
a
b Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series . 71 : 245.
Bibcode :
1989ApJS...71..245K .
doi :
10.1086/191373 .
^
a
b Massarotti, Alessandro; et al. (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 .
^ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters . 38 (5): 331.
arXiv :
1108.4971 .
Bibcode :
2012AstL...38..331A .
doi :
10.1134/S1063773712050015 .
S2CID
119257644 .
Vizier catalog entry
^
a
b
c Reffert, Sabine; et al. (2015). "Precise radial velocities of giant stars". Astronomy & Astrophysics . 574 : A116.
arXiv :
1412.4634 .
Bibcode :
2015A&A...574A.116R .
doi :
10.1051/0004-6361/201322360 .
hdl :
10722/215277 .
S2CID
59334290 .
Vizier catalog entry
^ De Medeiros, J. R.; et al. (2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics . 561 : A126.
arXiv :
1312.3474 .
Bibcode :
2014A&A...561A.126D .
doi :
10.1051/0004-6361/201220762 .
S2CID
54046583 .
Vizier catalog entry
^
a
b
"phi Oph" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 2021-01-24 .
^ 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 .
^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal , 539 (2): 732–741,
arXiv :
astro-ph/0003329 ,
Bibcode :
2000ApJ...539..732A ,
doi :
10.1086/309278 ,
S2CID
16673121
^ Stock, Stephan; et al. (August 2018), "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search", Astronomy & Astrophysics , 616 : 15,
arXiv :
1805.04094 ,
Bibcode :
2018A&A...616A..33S ,
doi :
10.1051/0004-6361/201833111 ,
S2CID
119361866 , A33
^ Luck, R. Earle (2015). "Abundances in the Local Region. I. G and K Giants". Astronomical Journal . 150 (3). 88.
arXiv :
1507.01466 .
Bibcode :
2015AJ....150...88L .
doi :
10.1088/0004-6256/150/3/88 .
S2CID
118505114 .
^ Mason, Brian D.; et al. (2001).
"The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog" . The Astronomical Journal . 122 (6): 3466.
Bibcode :
2001AJ....122.3466M .
doi :
10.1086/323920 .
Vizier catalog entry