Double star in the northern constellation Boötes
δ Boötis
Location of δ Boötis (circled)
Observation data
Epoch J2000
Equinox J2000
Constellation
Boötes
BD+33 2561
Right ascension
15h 15m 30.16295s
[1]
Declination
+33° 18′ 53.3926″
[1]
Apparent magnitude (V)
3.482
[2]
BD+33 2562
Right ascension
15h 15m 38.34898s
[3]
Declination
+33° 19′ 15.3187″
[3]
Apparent magnitude (V)
7.81
[4]
Characteristics
BD+33 2561
Spectral type
G8 III
[5]
U−B
color index
+0.656
[2] /
B−V
color index
+0.951
[2] /
BD+33 2562
Spectral type
G0 V
[4]
U−B
color index
+0.02
[4]
B−V
color index
+0.59
[4]
Astrometry BD+33 2561
Radial velocity (Rv ) −12.29± 0.16
[6] km/s
Proper motion (μ)
RA: +84.74
[1]
mas /
yr
Dec.: –111.58
[1]
mas /
yr
Parallax (π) 26.78 ± 0.16
mas
[1]
Distance 121.8 ± 0.7
ly (37.3 ± 0.2
pc )
Absolute magnitude (MV ) +0.700
[7] BD+33 2562
Radial velocity (Rv ) −11.83± 0.18
[3] km/s
Proper motion (μ)
RA: +82.776
[3]
mas /
yr
Dec.: –110.040
[3]
mas /
yr
Parallax (π) 27.0648 ± 0.0307
mas
[3]
Distance 120.5 ± 0.1
ly (36.95 ± 0.04
pc )
Details BD+33 2561
Radius 10.5± 0.2
[8]
R ☉
Luminosity 53.7
[7]
L ☉
Surface gravity (log g ) 2.56
[9]
cgs
Temperature 4,847
[9]
K
Metallicity [Fe/H]–0.44
[9]
dex
Rotational velocity (v sin i ) 3.6
[10] km/s BD+33 2562
Mass 0.98
[11]
M ☉
Radius 0.91± 0.02
[3]
R ☉ Luminosity 0.87
[11]
L ☉
Temperature 5,812± 67
[11]
K
Age 3.09
[11]
Gyr
Other designations A :
δ Boo ,
49 Boötis ,
BD +33 2561 ,
FK5 563,
HD 135722,
HIP 74666,
HR 5681,
SAO 64589
[12] B :
BD +33 2562 ,
HIP 74674,
SAO 64591
[13]
Database references
SIMBAD
data
SIMBAD
data
Delta Boötis ,
Latinized from δ Boötis, is a
double star in the northern
constellation of
Boötes , forming the easternmost member of the constellation's kite-shaped
asterism of brighter stars.
[14] Based upon
parallax measurements, it is located at a distance of approximately 121.8
light-years (37.3
parsecs ) from the
Earth .
[1] This star is sometimes called Princeps ,
[15] meaning prince or prime in
Latin . The origin of this name is unclear, although it usually appears in an
astrological context.
[16]
[17] The
apparent visual magnitude of this star is 3.5,
[2] making it visible to the naked eye
even during a Full Moon . The magnitude 7.81
[4] companion can be viewed in binoculars or a small telescope.
[14]
In
Chinese , 七公 (Qī Gōng ), meaning
Seven Excellencies , refers to an asterism consisting of δ Boötis,
42 Herculis ,
τ Herculis ,
φ Herculis ,
χ Herculis ,
ν1 Boötis and
μ1 Boötis .
[18] Consequently, the
Chinese name for δ Boötis itself is 七公七 (Qī Gōng qī , English: the Seventh Star of Seven Excellencies .)
[19]
Properties
δ Boötis in optical light
This system consists of a pair of stars located in physical proximity to each other and sharing a similar motion through space, suggesting that they may form a
binary star system. Based upon their angular separation and their distance, they have a
projected separation of 3,800
Astronomical Units (AU). If they are gravitationally bound to each other, the
orbital period of the system would be at least 120,000 years.
[20]
The brighter member of the pair has a
stellar classification of G8 III,
[5] indicating that it has exhausted the supply of hydrogen at its core and
evolved into a
giant star . It now has a radius more than ten times the radius of the Sun.
[8] Compared to the
Sun , this star appears deficient in elements other than hydrogen and helium—what astronomers term the star's
metallicity . The outer envelope of this star has an
effective temperature of 4,847 K,
[9] which is what gives it the characteristic yellow hue of a
G-type star .
[21]
The secondary component has a stellar classification of G0 V,
[4] which suggests it is a
main sequence star that may be similar in physical properties to the Sun. The apparent visual magnitude of this star is 7.81,
[4] making it much less luminous than the primary component.
[22]
References
^
a
b
c
d
e
f van Leeuwen, F. (November 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 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
c
d
e
f
g
Brown, A. G. A. ; et al. (Gaia collaboration) (August 2018).
"Gaia Data Release 2: Summary of the contents and survey properties" .
Astronomy & Astrophysics . 616 . A1.
arXiv :
1804.09365 .
Bibcode :
2018A&A...616A...1G .
doi :
10.1051/0004-6361/201833051 .
Gaia DR2 record for this source at
VizieR .
^
a
b
c
d
e
f
g Tolbert, Charles Ray (May 1964), "A UBV Study of 94 Wide Visual Binaries", Astrophysical Journal , 139 : 1105,
Bibcode :
1964ApJ...139.1105T ,
doi :
10.1086/147852
^
a
b Tsvetkov, A. S.; Popov, A. V.; Smirnov, A. A. (January 2008), "Inaccuracies in the spectral classification of stars from the Tycho-2 Spectral Type Catalogue", Astronomy Letters , 34 (1): 17–27,
Bibcode :
2008AstL...34...17T ,
doi :
10.1134/S1063773708010039 ,
S2CID
119468042
^ 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 .
^
a
b Böhm-Vitense, Erika; et al. (December 2000), "Ultraviolet Emission Lines in BA and Non-BA Giants", The Astrophysical Journal , 545 (2): 992–999,
Bibcode :
2000ApJ...545..992B ,
doi :
10.1086/317850 .
^
a
b Nordgren, Tyler E.; et al. (December 1999),
"Stellar Angular Diameters of Late-Type Giants and Supergiants Measured with the Navy Prototype Optical Interferometer" , The Astronomical Journal , 118 (6): 3032–3038,
Bibcode :
1999AJ....118.3032N ,
doi :
10.1086/301114 {{
citation }}
: CS1 maint: multiple names: authors list (
link )
^
a
b
c
d 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
^ 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
^
a
b
c
d 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 .
^
a
b
"del Boo" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 2021-06-14 .
^
"BD+33 2562" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 2021-06-14 .
^
a
b English, Neil (May 14, 2014),
Grab 'n' Go Astronomy , Springer New York, p. 214,
Bibcode :
2014gnga.book.....E ,
ISBN
9781493908264 .
^
"princeps" .
Oxford English Dictionary (Online ed.).
Oxford University Press . (Subscription or
participating institution membership required.)
^ Robson, Vivian E. (2005),
The Fixed Stars and Constellations in Astrology , Astrology Center of America, p. 112,
ISBN
1-933303-13-1
^
"Princeps – Constellations of Words" . Retrieved 2022-10-28 .
^ (in Chinese) 中國星座神話 , written by 陳久金. Published by 台灣書房出版有限公司, 2005,
ISBN
978-986-7332-25-7 .
^ (in Chinese)
AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 26 日
^ Kaler, James B.,
"DELTA BOO (Delta Bootis)" , Stars ,
University of Illinois , retrieved 2012-01-05
^
"The Colour of Stars" , Australia Telescope, Outreach and Education ,
Commonwealth Scientific and Industrial Research Organisation , December 21, 2004, archived from
the original on 2012-03-18, retrieved 2012-01-16
^ The actual brightness ratio is given by 2.512Δm , where Δm is the difference in magnitude. For this pair, Δm = –4.33, so the ratio is 2.512−4.33 = 0.019. Hence the secondary component is 1.9% as bright as the primary.
External links