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Star system in the constellation Cancer
Gamma Cancri
Location of γ Cancri (circled)
Observation data
Epoch
J2000.0
Equinox
J2000.0 (
ICRS )
Constellation
Cancer
Right ascension
08h 43m 17.14820s
[1]
Declination
+21° 28′ 06.6008″
[1]
Apparent magnitude (V)
4.673
[2]
Characteristics
Spectral type
A1IV
[3]
U−B
color index
+0.03
[4]
B−V
color index
+0.010
[2]
Astrometry
Radial velocity (Rv ) 28.7
[5] km/s
Proper motion (μ)
RA: −103.51
[1]
mas /
yr
Dec.: −39.48
[1]
mas /
yr
Parallax (π) 18.00 ± 0.21
mas
[1]
Distance 181 ± 2
ly (55.6 ± 0.6
pc )
Absolute magnitude (MV ) +1.1
[6]
Details
Mass 2.18
[7]
M ☉
Radius 2.5
[8]
R ☉
Luminosity 36
[9]
L ☉
Surface gravity (log g ) 4.17
[7]
cgs
Temperature 9,108
[9]
K
Rotational velocity (v sin i ) 86± 6
[10] km/s
Age 171
[7]
Myr
Other designations Asellus Borealis,
γ Cnc, Gamma Cnc ,
43 Cnc ,
BD +21° 1895 ,
FK5 1228,
GC 11982,
HD 74198,
HIP 42806,
HR 3449,
SAO 80378,
CCDM 08433+2128
[11]
Database references
SIMBAD
data
Gamma Cancri , or γ Cancri , is a
star in the northern
constellation of
Cancer . It is formally named Asellus Borealis , the traditional name of the system.
[12] Based on
parallax measurements, it is located at a distance of approximately 181
light years from the
Sun . The star is drifting further away with a
radial velocity of 29 km/s.
[5] In 1910 this star was reported to be a
spectroscopic binary by
O. J. Lee ,
[13] but is now considered a single star.
[14]
[15] Since it is near the
ecliptic , it can be
occulted by the
Moon
[16] and, very rarely, by
planets .
Nomenclature
γ Cancri (
Latinised to Gamma Cancri ) is the star's
Bayer designation . It bore the traditional name Asellus Borealis (
Latin for "northern
donkey ").
[17] In 2016, the
International Astronomical Union organized a
Working Group on Star Names (WGSN)
[18] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire
multiple systems .
[19] It approved the name Asellus Borealis for the star on 6 November 2016 and it is now so included in the List of IAU-approved Star Names.
[12] Together with
Delta Cancri , it formed the Aselli , flanking
Praesepe .
[20]
In
Chinese astronomy ,
Ghost (
Chinese : 鬼宿 ;
pinyin : Guǐ Xiù ) refers to an
asterism consisting of
Theta Cancri ,
Eta Cancri , Gamma Cancri and Delta Cancri.
[21] Gamma Cancri itself is known as the third star of Ghost (
Chinese : 鬼宿三 ;
pinyin : Guǐ Xiù sān ).
[22]
Properties
Gamma Cancri presents as a white
A-type
subgiant with an
apparent magnitude of +4.67.
[3] The star is an estimated 171
[7] million years old and is spinning with a
projected rotational velocity of 86 km/s.
[10] It has 2.18
[7] times the
mass of the Sun and shines with a
luminosity approximately 36 times greater at an
effective temperature of 9108 K.
[9]
It has been included as a member of the
Hyades Stream based on its distance, space motion, and likely age.
[23]
References
^
a
b
c
d
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18759600 .
^
a
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arXiv :
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^
a
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"The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars" . Astrophysical Journal Supplement . 95 : 135.
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Bibcode :
1986EgUBV........0M .
^
a
b Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication .
Bibcode :
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^ Eggen, O. J.; Iben, Icko Jr. (1988).
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^
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e David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal . 804 (2): 146.
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Vizier catalog entry
^ Pasinetti Fracassini, L. E.; et al. (2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics". Astronomy & Astrophysics . 367 (2): 521–24.
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^
a
b
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^
a
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^
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^
a
b
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^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems".
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^ De Rosa, R. J.; et al. (July 2011). "The Volume-limited A-Star (VAST) survey - I. Companions and the unexpected X-ray detection of B6-A7 stars". Monthly Notices of the Royal Astronomical Society . 415 (1): 854–866.
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^
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^
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^ Richard H. Allen (28 February 2013).
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^
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