Sigma Boötis

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σ Boötis
Observation data Epoch J2000 Equinox J2000
Constellation	Boötes
Right ascension	14^h 34^m 40.8171^s
Declination	+29° 44′ 42.468″
Apparent magnitude (V)	4.46
Characteristics
Spectral type	F2V
U−B color index	-0.08
B−V color index	0.36
R−I color index	0.19
Variable type	Variable star
Astrometry

Radial velocity (R_v)	0.2 km/s
Proper motion (μ)	RA: 188.32 mas/yr Dec.: 132.72 mas/yr
Parallax (π)	64.66 ± 0.72 mas
Distance	50.4 ± 0.6 ly (15.5 ± 0.2 pc)
Absolute magnitude (M_V)	4.82

Details

Radius	1.431 ± 0.023^[1] R_☉
Luminosity	3.461 ± 0.042^[1] L_☉
Temperature	6,594 ± 55^[1] K
Age	1.7^[2] Gyr

Other designations
28 Boötis, HR 5447, HD 128167, Gl 557, BD+30°2536, FK5 1380, HIP 71284, SAO 83416, GC 19659, CCDM 14347+2945.
Database references
SIMBAD	data
Data sources:
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.)
Database references
SIMBAD	data

Sigma Boötis (σ Boo, σ Boötis) is a star in the constellation Boötes.

Sigma Boötis is a yellow-white F-type main sequence dwarf with an apparent magnitude of +4.47. It is approximately 50.4 light years from Earth.

In Chinese, 梗河 (Gěng Hé), meaning Celestial Lance, refers to an asterism consisting of σ Boötis, ε Boötis and ρ Boötis.^[3] Consequently, σ Boötis itself is known as 梗河二 (Gěng Hé èr, English: the Second Star of Celestial Lance.)^[4]

Located to the southeast of Rho Boötis, the fusing dwarf Sigma may at first appear as a naked-eye double, but the angular proximity with Rho is merely line-of-sight. Like many of its spectral class, Sigma is apparently a variable of the Delta Scuti variety, which vary subtly with multiple periods of hours.

References

↑ 1.0 1.1 1.2 Boyajian, Tabetha S. et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101 . See Table 10.
↑ Decin, G. et al. (November 2003), "Age Dependence of the Vega Phenomenon: Observations", The Astrophysical Journal 598 (1): 636–644, arXiv:astro-ph/0308294, Bibcode:2003ApJ...598..636D, doi:10.1086/378800
↑ (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.
↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 29 日

External links

← Star systems within 50–55 light-years →

Star systems (including brown dwarf systems) within 50–55 light-years from Earth.

A V (White)	Castor (51.6 ± 1.0 ly; 6 stars)

F
(Yellow-white)

IV	Delta Aquilae «Denebokab» (50.1 ± 0.6 ly; 3 stars) I Carinae (52.9 ± 0.4 ly; 1 star) Beta Cassiopeiae «Caph» (54.5 ± 0.5 ly; 2 stars)

V	Phi² Ceti (50.4 ± 0.8 ly; 1 star) Sigma Boötis «Hemelein Secunda» (50.4 ± 0.6 ly; 2 stars) 99 Herculis (50.5 ± 0.6 ly; 3 stars) Tau Boötis (50.9 ± 0.6 ly; 2 stars, 1 planet: b) Chi Herculis (51.7 ± 0.4 ly; 1 star) Xi Pegasi (53.0 ± 0.7 ly; 2 stars) 10 Ursae Majoris (53.0 ± 0.9 ly; 2 stars) Alpha Circini (53.5 ± 0.5 ly; 2 stars)

G V
(Yellow)

51 Pegasi (50.1 ± 0.6 ly; 1 star, 1 planet: b «Bellerophon»)
GJ 3233 (50.2+6.0
−4.9 ly; 1 star)
Gliese 758 (50.5 ± 0.5 ly; 1 star, 1 brown dwarf: B)
HD 38858 (50.8 ± 0.9 ly; 1 star, 1 planet: b)
HR 8323 (51.0 ± 0.6 ly; 1 star)
104 Tauri (51.8 ± 0.8 ly; 2 stars)
Gliese 777 (51.8 ± 0.5 ly; 3 stars, 2 planets: c
b)
GJ 3781 (52.3 ± 1.2 ly; 2 stars)
HR 3138 (52.8 ± 0.4 ly; 3 stars)
9 Puppis (53.4 ± 0.8 ly; 2 stars)
Psi⁵ Aurigae (53.9 ± 0.6 ly; 1 star)
HD 53705/53706/53680 (53.9 ± 0.9 ly; 4 stars)
HR 5273 (54.1 ± 0.7 ly; 2 stars)
HR 2225 (54.5 ± 0.7 ly; 1 star)
39 Tauri (54.6 ± 0.8 ly; 2 stars)
Gliese 295 (54.8 ± 0.7 ly; 1 star)
HR 2721 (55.0 ± 0.6 ly; 1 star)

K V
(Orange)

HR 159 (50.2 ± 0.8 ly; 2 stars)
Gliese 156 (50.3 ± 0.9 ly; 1 star)
Gliese 862 (50.4 ± 0.8 ly; 1 star)
Gliese 227 (50.4 ± 0.7 ly; 1 star)
HD 135599 (50.8 ± 0.8 ly; 1 star)
Gliese 778 (50.8 ± 0.7 ly; 1 star)
GJ 1175 (50.9 ± 0.6 ly; 1 star)
Gliese 782 (51.1 ± 1.2 ly; 1 star)
Gliese 397 (51.1 ± 1.0 ly; 1 star)
HD 113538 (51.2 ± 1.1 ly; 1 star, 2 planets: b
c)
HD 139763 (51.3 ± 1.1 ly; 1 star)
Gliese 157 (51.4 ± 1.7 ly; 3 stars)
Gliese 619 (51.9 ± 0.7 ly; 1 star)
Gliese 112.1 (51.9 ± 1.3 ly; 1 star)
Gliese 156.2 (52.1 ± 0.7 ly; 1 star)
Gliese 462 (52.2 ± 1.1 ly; 1 star)
Gliese 3 (52.2 ± 0.7 ly; 1 star)
Gliese 32 (52.3 ± 1.4 ly; 2 stars)
Gliese 472 (52.8 ± 0.5 ly; 1 star)
Gliese 824 (52.8 ± 0.9 ly; 1 star)
Gliese 152 (52.9 ± 0.6 ly; 1 star)
Gliese 143 (53.4 ± 1.3 ly; 1 star)
GJ 1177 (53.4 ± 2.7 ly; 2 stars)
Gliese 826.1 (53.4 ± 1.2 ly; 1 star)
Gliese 247 (53.5 ± 1.2 ly; 1 star)
BY Draconis (53.6 ± 0.6 ly; 1 star)
Gliese 531 (53.6 ± 0.8 ly; 1 star)
Gliese 322 (53.8 ± 1.3 ly; 1 star)
Gliese 553 (53.9 ± 1.4 ly; 1 star)
HD 128311 (54.0 ± 0.9 ly; 1 star, 2 planets: b
c)
Gliese 795 (54.5 ± 2.0 ly; 2 stars)
A 2329 (54.6 ± 1.1 ly; 2 stars)
GJ 1181 (54.8 ± 2.5 ly; 2 stars)
Gliese 786 (54.8 ± 0.7 ly; 1 star)
HD 7924 (54.9 ± 0.5 ly; 1 star, 1 planet: b)
Gliese 895.4 (55.0 ± 0.6 ly; 1 star)
Gliese 200 (55.0 ± 1.6 ly; 2 stars)

M V (Red dwarf)	GJ 3685/3686 (50.7+11.8 −8.0 ly; 2 stars) GJ 1062 (52.3 ± 2.9 ly; 1 star) HD 179930 (52.5 ± 1.7 ly; 2 stars) GJ 1264 (52.6 ± 2.1 ly; 1 star) Gliese 676 (53.7 ± 1.5 ly; 2 stars, 4 planets: Ad Ae Ab Ac) GJ 1049 (53.9 ± 1.2 ly; 1 star)

White
dwarf

DA	BPM 37093 (53.5+9.7 −7.1 ly; 1 star)

Brown
dwarf

WISE 0614+3912 (~50.2 ly; 1 brown dwarf)
WISE 1617+1807 (~50.2 ly; 1 brown dwarf)
WISE 1627+3255 (~50.2 ly; 1 brown dwarf)
WISE 0542-1628 (~50.6 ly; 1 brown dwarf)
WISE 1124-0421 (~50.6 ly; 1 brown dwarf)
WISE 2015+6646 (~50.6 ly; 1 brown dwarf)
WISE 1519+7009 (~50.9 ly; 1 brown dwarf)
WISE 0325-3854 (~51.2 ly; 1 brown dwarf)
WISE 2342+0856 (~51.2 ly; 1 brown dwarf)
WISE 0614+0951 (~51.5 ly; 1 brown dwarf)
WISE 0750+2725 (~51.5 ly; 1 brown dwarf)
WISE 0906+4735 (~51.5 ly; 1 brown dwarf)
WISE 1906+4508 (~51.5 ly; 1 brown dwarf)
WISE 1457+5815 (~52.2 ly; 1 brown dwarf)
WISE 2319-1844 (~52.2 ly; 1 brown dwarf)
WISE 1622-0959 (52.2 ± 6.5 ly; 1 brown dwarf)
WISE 1042-3842 (~53.2 ly; 1 brown dwarf)
WISE 2237-0614 (~53.5 ly; 1 brown dwarf)
WISE 0241-3653 (~53.8 ly; 1 brown dwarf)
WISE 0656+4205 (~54.1 ly; 1 brown dwarf)
WISE 2348-1028 (~54.1 ly; 1 brown dwarf)
WISE 1804+3117 (54.4+12.2
−8.4 ly; 1 brown dwarf)
WISE 0148+7202 (54.4+19.8
−11.4 ly; 1 brown dwarf)
WISE 0333-5856 (~54.8 ly; 1 brown dwarf)
WISE 2357+1227 (~54.8 ly; 1 brown dwarf)

In left column are stellar classes of primary members of star systems. Bold are systems containing at least one component with absolute magnitude of +8.5 or brighter. Italic are systems without known trigonometric parallax.

v t e Stars of Boötes

Bayer	α (Arcturus) β (Nekkar) γ (Seginus) δ ε (Izar) ζ η (Muphrid) θ (Asellus Primus) ι (Asellus Secundus) κ (Asellus Tertius) λ μ (Alkalurops) ν¹ ν² ξ ο π ρ σ τ υ φ (Ceginus) χ ψ ω

Flamsteed	1 2 3 6 (e) 7 9 10 11 12 (d) 13 14 15 18 20 22 (f) 24 (g) 26 31 32 33 34 38 (h, Merga) 39 40 44 (i) 45 (c) 46 (b) 47 (k) 50 101 Vir

Variable	R S V RS RV RX SS ST SW TU TY TZ UU UY UZ VW XY YZ ZZ AC AD AR BP BX BY CH CI CK CN CP CR DE EF EK GU HN HP

HR	5123 5129 5137 5138 5156 5164 5220 5243 5254 5262 5270 5273 5274 5310 5335 5333 5346 5347 5360 5361 (A) 5363 5372 5373 5374 5385 5387 5388 5394 5402 5416 5422 5423 5433 5445 5448 5454 5462 5464 5467 5472 5473 5483 5493 5507 5510 5524 5529 5532 5537 5541 5550 5567 5569 5574 5575 5581 5592 5609 5630 5633 5635 5639 5640 5648 5673 5674 5677 5715 5716 5726 5741 5752 5830 5835

HD	119784 122443 124678 125076 126307 129357 131496 132406 132563 135944 136418

Gliese	GJ 526 Gliese 569

Other	CFBDSIR 1458+10 G 166-45 GD 165 HAT-P-4 LHS 2924 LkCa 19 2MASS 1503+2525 PSR J1518+4904 SDSS J1416+1348 Sigma 1785 TVLM513-46546 WASP-14

List

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