From Wikipedia, the free encyclopedia
Star in the constellation Ursa Major
Psi Ursae Majoris
Location of ψ Ursae Majoris (circled)
Observation data
Epoch
J2000.0
Equinox
J2000.0 (
ICRS )
Constellation
Ursa Major
Right ascension
11h 09m 39.8083s
[1]
Declination
+44° 29′ 54.5559″
[1]
Apparent magnitude (V)
+3.01
[2]
Characteristics
Evolutionary stage
Giant star
Spectral type
K1 III
[3]
U−B
color index
+1.12
[2]
B−V
color index
+1.14
[2]
Astrometry
Radial velocity (Rv ) –3.39
[4] km/s
Proper motion (μ)
RA: –62.02
mas /
yr
[1]
Dec.: –27.78
mas /
yr
[1]
Parallax (π) 23.2272 ± 0.2513
mas
[1]
Distance 140 ± 2
ly (43.1 ± 0.5
pc )
[1]
Absolute magnitude (MV ) −0.27
[5]
Details
Mass 3.96
[6]
M ☉
Radius 20.79
[6]
R ☉
Luminosity 148 ± 12
[7]
L ☉
Surface gravity (log g ) 2.4
[6]
cgs
Temperature 4,540
[6]
K
Metallicity [Fe/H]–0.072
[6]
dex
Rotational velocity (v sin i ) 5.5
[8] km/s
Other designations ψ Ursae Majoris, ψ UMa, Psi UMa, 52 Ursae Majoris,
BD +45 1897,
FK5 420,
GC 15340,
HD 96833,
HIP 54539,
HR 4335,
PPM 52277,
SAO 43629.
[9]
Database references
SIMBAD
data
Psi Ursae Majoris (Psi UMa , ψ Ursae Majoris , ψ UMa ) is a
star in the northern
circumpolar constellation of
Ursa Major . It has an
apparent visual magnitude of +3.01,
[2] making it a third magnitude star and one of the brighter members of the constellation.
Parallax measurements place it at a distance of 140
light-years (43
parsecs ) from Earth.
[1] This is sufficiently close that the magnitude of the star is only reduced by 0.05 due to
extinction .
[4] In
Chinese astronomy , Psi Ursae Majoris is called Tien Tsan or Ta Tsun , "Extremely Honorable".
[10] The name was possibly derived from the word 太尊,
Pinyin : Tàizūn, meaning Royals , because this star stands alone as the only member of the Royals asterism within the
Purple Forbidden enclosure (see
Chinese constellation ).
The
spectrum of this star matches a
stellar classification of K1 III,
[3] with the
luminosity class of 'III' indicating this is an
evolved
giant star that has exhausted the supply of hydrogen at its core. As a consequence, it has expanded to around 21 times the radius of the Sun.
[6] It is radiating roughly 148
[7] times the luminosity of the Sun from its enlarged
outer envelope at an
effective temperature of 4,540 K.
[6] At this heat, the star glows with the orange hue of a
K-type star .
[11]
Psi Ursae Majoris is a member of the
thin disk population of the
Milky Way . It is following an orbit through the galaxy with a low
eccentricity of 0.02 that will carry it between 26.5–27.8
kly (8.1–8.5
kpc ) from the
Galactic Center . The low inclination of its orbit means the star will only stray 130 ly (40 pc) from the
galactic plane .
[12]
References
^
a
b
c
d
e
f 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 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.",
Monthly Notices of the Royal Astronomical Society , 172 (3): 667–679,
Bibcode :
1975MNRAS.172..667J ,
doi :
10.1093/mnras/172.3.667
^
a
b Frasca, A.; et al. (December 2009), "REM near-IR and optical photometric monitoring of pre-main sequence stars in Orion. Rotation periods and starspot parameters", Astronomy and Astrophysics , 508 (3): 1313–1330,
arXiv :
0911.0760 ,
Bibcode :
2009A&A...508.1313F ,
doi :
10.1051/0004-6361/200913327 ,
S2CID
118361131
^
a
b 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 : 165–186,
arXiv :
astro-ph/0409579 ,
Bibcode :
2005A&A...430..165F ,
doi :
10.1051/0004-6361:20041272 ,
S2CID
17804304
^ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics , 430 : 303–311,
arXiv :
astro-ph/0409683 ,
Bibcode :
2005A&A...430..303C ,
doi :
10.1051/0004-6361:20041440 ,
S2CID
12136256 .
^
a
b
c
d
e
f
g Gray, David F.; Kaur, Taranpreet (2019-09-01).
"A Recipe for Finding Stellar Radii, Temperatures, Surface Gravities, Metallicities, and Masses Using Spectral Lines" . The Astrophysical Journal . 882 (2): 148.
Bibcode :
2019ApJ...882..148G .
doi :
10.3847/1538-4357/ab2fce .
ISSN
0004-637X .
^
a
b Piau, L.; et al. (February 2011), "Surface convection and red-giant radius measurements", Astronomy and Astrophysics , 526 : A100,
arXiv :
1010.3649 ,
Bibcode :
2011A&A...526A.100P ,
doi :
10.1051/0004-6361/201014442 ,
S2CID
118533297
^ 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 .
^
"psi UMa -- Star" , SIMBAD , Centre de Données astronomiques de Strasbourg, retrieved 2012-01-16
^ Allen, Richard Hinckley (1963),
Star Names — Their Lore and Meaning: Ursa Major (Dover ed.),
University of Chicago
^
"The Colour of Stars" , Australia Telescope, Outreach and Education , Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from
the original on March 18, 2012, retrieved 2012-01-16
^ Soubiran, C.; et al. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics , 480 (1): 91–101,
arXiv :
0712.1370 ,
Bibcode :
2008A&A...480...91S ,
doi :
10.1051/0004-6361:20078788 ,
S2CID
16602121