Binary star in the constellation Ursa Major
Phi Ursae Majoris
Location of φ Ursae Majoris (circled)
Observation data
Epoch
J2000.0
Equinox
J2000.0
Constellation
Ursa Major
Right ascension
09h 52m 06.35437s
[1]
Declination
+54° 03′ 51.5962″
[1]
Apparent magnitude (V)
+4.60
[2] (5.28 + 5.39)
[3]
Characteristics
Spectral type
A3 IV + A3 IV
[4]
U−B
color index
+0.08
[2]
B−V
color index
+0.03
[2]
Astrometry
Radial velocity (Rv ) −14.7± 0.3
[5] km/s
Proper motion (μ)
RA: −6.00
[1]
mas /
yr
Dec.: +19.16
[1]
mas /
yr
Parallax (π) 6.41 ± 0.59
mas
[1]
Distance 510 ± 50
ly (160 ± 10
pc )
Absolute magnitude (MV ) −1.39
[6]
Orbit
[7]
Period (P) 104.6
yr
Semi-major axis (a) 0.329″
Eccentricity (e) 0.436
Inclination (i) 19.4°
Longitude of the node (Ω) 132.5°
Periastron
epoch (T) 1987.52
Argument of periastron (ω) (secondary)33.3°
Details A
Mass 3.5± 0.2
[8]
M ☉
Luminosity 347
[8]
L ☉
Surface gravity (log g ) 3.69± 0.16
[9]
cgs
Temperature 8,769± 150
[9]
K
Metallicity [Fe/H] −0.23± 0.08
[9]
dex
Rotational velocity (v sin i ) 28
[8] km/s
Other designations
φ UMi ,
30 Ursae Majoris ,
BD +54°1331 ,
GC 13559,
HD 85235,
HIP 48402,
HR 3894,
SAO 27408,
PPM 32355,
CCDM J09521+5404AB ,
WDS J09521+5404AB
[10]
Database references
SIMBAD
data
Phi Ursae Majoris , Latinized from φ Ursae Majoris , is
binary star
[11] system in the
northern
constellation of
Ursa Major . It is white-hued and is visible to the naked eye with a combined
apparent visual magnitude of +4.60;
[2] the primary is magnitude 5.28 while the secondary is magnitude 5.39.
[11] The system is located at a distance of approximately 510
light-years (160
parsecs ) from the
Sun based on
parallax ,
[1] but is drifting closer with a
radial velocity of −14.7 km/s.
[5] It should make its closest approach at a distance of around 370 light-years in about 4.7 million years.
[6]
As of 2017, the components had an
angular separation of 0.50
″ along a
position angle of 304°.
[3] They are orbiting each other with a
period of 105.4 years and
eccentricity of 0.44.
[7] Both of components are
A-type
subgiant stars
[12] with a
stellar classification of A3 IV.
[4]
Phi Ursae Majoris is moving through the galaxy at a speed of 21.6 km/s relative to the Sun. Its projected galactic orbit carries it between 24,000 and 46,000 light-years from the center of the galaxy.
[6]
Naming
With
τ ,
h ,
υ ,
θ ,
e , and
f , it composed the Arabic
asterism Sarīr Banāt al-Na'sh , the Throne of the daughters of Na'sh , and Al-H aud , the Pond.
[13] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars , Al-H aud were the title for seven stars:
f as Alhaud I ,
τ as Alhaud II ,
e as Alhaud III ,
h as Alhaud IV ,
θ as Alhaud V ,
υ as Alhaud VI and this star (φ) as Alhaud VII .
[14]
In
Chinese , 文昌 (Wén Chāng ), meaning
Administrative Center , refers to an asterism consisting of φ Ursae Majoris,
υ Ursae Majoris ,
θ Ursae Majoris ,
15 Ursae Majoris and
18 Ursae Majoris . Consequently, the
Chinese name for φ Ursae Majoris itself is known as 文昌三 (Wén Chāng sān , English: the Third Star of Administrative Center ).
[15]
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 .
^
a
b
c
d Johnson, H. L. (1966), "UBVRIJKL Photometry of the Bright Stars", Communications of the Lunar and Planetary Laboratory , 4 : 99,
Bibcode :
1966CoLPL...4...99J .
^
a
b Mason, B. D.; et al. (2014),
"The Washington Visual Double Star Catalog" , The Astronomical Journal , 122 (6): 3466,
Bibcode :
2001AJ....122.3466M ,
doi :
10.1086/323920 , retrieved 2015-07-22
^
a
b Edwards, T. W. (April 1976), "MK classification for visual binary components", Astronomical Journal , 81 : 245–249,
Bibcode :
1976AJ.....81..245E ,
doi :
10.1086/111879 .
^
a
b Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters , 32 (11): 759–771,
arXiv :
1606.08053 ,
Bibcode :
2006AstL...32..759G ,
doi :
10.1134/S1063773706110065 ,
S2CID
119231169 .
^
a
b
c 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 .
^
a
b Hartkopf, W. I.; et al. (June 30, 2006),
Sixth Catalog of Orbits of Visual Binary Stars , United States Naval Observatory, retrieved 2017-06-02 .
^
a
b
c Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics , 537 : A120,
arXiv :
1201.2052 ,
Bibcode :
2012A&A...537A.120Z ,
doi :
10.1051/0004-6361/201117691 ,
S2CID
55586789 .
^
a
b
c Prugniel, P.; et al. (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 .
^
"phi UMa" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 18 February 2017 .
^
a
b 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 .
^ Kaler, James B. (April 23, 2010),
"PHI UMA (Phi Ursae Majoris)" , STARS , retrieved 2019-10-12 .
^
Allen, Richard Hinckley (1899), Star-Names and Their Meanings , New York: G. E. Stechert, p. 442
^ Rhoads, Jack W. (November 15, 1971),
Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF) , Jet Propulsion Laboratory, California Institute of Technology.
^ (in Chinese)
AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 16 日