Sigma Boötis

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σ Boötis
Bootes IAU.svg
Red circle.svg
Location of σ Boötes (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Boötes
Right ascension 14h 34m 40.81718s [1]
Declination +29° 44′ 42.4637″ [1]
Apparent magnitude  (V)4.46 [2]
Characteristics
Spectral type F4VkF2mF1 [3]
U−B color index −0.084 [2]
B−V color index +0.366 [2]
Variable type Suspected [4]
Astrometry
Radial velocity (Rv)+0.37±0.09 [5]  km/s
Proper motion (μ)RA: +188.762 [1]   mas/yr
Dec.: +131.222 [1]   mas/yr
Parallax (π)63.8633 ± 0.2303  mas [1]
Distance 51.1 ± 0.2  ly
(15.66 ± 0.06  pc)
Absolute magnitude  (MV)3.52 [6]
Details
Mass 1.48 M☉ [7]
1.18 [8]   M☉
Radius 1.431±0.023 [9]   R☉
Luminosity 3.461±0.042 [9]   L☉
Surface gravity (log g)4.30 [6]   cgs
Temperature 6,594±55 [9]   K
Metallicity [Fe/H]−0.24 [10]   dex
Rotational velocity (v sin i)7.32 [11]  km/s
Age 1.7 Gyr [12]
2.42 Gyr [8]
3.1 [13]   Gyr
Other designations
σ Boo, 28 Boötis, BD+30°2536, GC  19659, GJ  557, HD  128167, HIP  71284, HR  5447, SAO  83416, CCDM 14347+2945 [14]
Database references
SIMBAD data

Sigma Boötis, its name Latinized from σ Boötis, is a single [15] [16] star in the northern constellation of Boötes. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude of 4.46. [2] Located to the southeast of Rho Boötis, the dwarf Sigma may at first appear as a naked-eye double, but the angular proximity with Rho is merely line-of-sight. Sigma Boötis is located at a distance of 51.1  light years from the Sun based on parallax. [1] The star has a relatively high proper motion and is traversing the sky at the rate of 0.230″  yr−1. [17]

Contents

The stellar classification of Sigma Boötis is F4VkF2mF1. [3] This notation is used for so-called "metal-weak" stars, Am stars with absorption lines of some metals weaker than expected in comparison with other spectral features. The 'F4V', indicating an F-type main-sequence star, is derived from the hydrogen spectral lines and the shape of the metallic lines, the 'kF2' meaning it has the Calcium K line strength of an F2 star and 'mF1' showing it has the metallic line strength of an F1 star. [18] It is around twice as luminous as a comparable zero age main sequence star, which may indicate it is near the end of its main sequence lifetime. [13]

Sigma Boötis is a solar-type star but is larger and more massive than the Sun. It has an estimated age of around two [12] to three [13] billion years and is spinning with a projected rotational velocity of 7 km/s. [11] There is some evidence of variation in radial velocity as well as rotational modulation of active latitudes. [13] Even though the outer convective zone of the star only occupies a few percent of the stellar radius, a surface magnetic field has been detected with a strength of 1.4±0.4  Gauss . [19] The star is radiating 3.5 [9] times the luminosity of the Sun from its photosphere at an effective temperature of 6,594 K. [9] It appears to be a source for X-ray emission. [20]

Infrared surveys with the Spitzer and Herschel space telescopes failed to detect an infrared excess around this star at wavelengths up to 160 μm. However, the HOSTS Survey with the Large Binocular Telescope reported a detection of an excess in the far infrared, indicating the presence of exozodiacal dust near the habitable zone of the star. [21]

Nomenclature

Sigma Boötis is known by several different names, including σ Boo, 28 Boötis, BD+30°2536, GC 19659, GJ 557, HD 128167, HIP 71284, HR 5447, SAO 83416, and CCDM 14347+2945. [14]

Chinese name

In Chinese, 梗河 (Gěng Hé), meaning Celestial Lance , refers to an asterism consisting of σ Boötis, ε Boötis and ρ Boötis. [22] Consequently, the Chinese name for σ Boötis itself is 梗河二 (Gěng Hé èr, English: the Second Star of Celestial Lance.) [23]

Related Research Articles

<span class="mw-page-title-main">Tau Boötis</span> Star in the constellation of Boötes

Tau Boötis, Latinised from τ Boötis, is an F-type main-sequence star approximately 51 light-years away in the constellation of Boötes. It is a binary star system, with the secondary star being a red dwarf. In 1999, an extrasolar planet was detected orbiting the primary star.

<span class="mw-page-title-main">Sigma Draconis</span> Star in the constellation Draco

Sigma Draconis is a single star in the northern constellation of Draco. It has the proper name Alsafi, while Sigma Draconis, which is latinised from σ Draconis and abbreviated Sig Dra or σ Dra, is the Bayer designation. It has an apparent visual magnitude of 4.7, which is bright enough to be faintly visible to the naked eye. Based on parallax measurements, this star is located at a distance of 18.8 light years from the Sun. It is receding from the Sun with a radial velocity of 26.6 km/s.

Xi Boötis, Latinised from ξ Boötis, is a binary star system located at a distance of 22 light-years away from Earth. It is the nearest visible star in the constellation Boötes. The brighter, primary component of the pair has a visual magnitude of 4.70, making it visible to the naked eye.

Sigma Serpentis, Latinized from σ Serpentis, is a star in the equatorial constellation Serpens. It is faintly visible to the naked eye with an apparent visual magnitude of +4.82. Based upon an annual parallax shift of 36.67 mas as seen from Earth, it is located 89 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −49 km/s.

<span class="mw-page-title-main">Rho Virginis</span> Variable A-type main sequence star in the constellation Virgo

Rho Virginis is the Bayer designation for a star in the constellation Virgo. It has an apparent visual magnitude of +4.9, making it a challenge to view with the naked eye from an urban area. The distance to this star has been measured directly using the parallax method, which places it 118.3 light-years away with a margin of error of about a light year.

<span class="mw-page-title-main">Sigma Andromedae</span> Star in the constellation Andromeda

Sigma Andromedae, Latinized from σ Andromedae, is the Bayer designation for a single star in the northern constellation of Andromeda. It has an apparent visual magnitude of +4.5, which is bright enough to be seen with the naked eye from most locations. Parallax measurements made during the Gaia mission place it at a distance of about 140 light-years. The magnitude of the star is diminished by 0.08 from extinction caused by intervening gas and dust. It is drifting closer to the Sun with a radial velocity of –8 km/s.

Nu<sup>1</sup> Boötis Orange-hued star in the constellation Boötes

Nu1 Boötis (ν1 Boötis) is an orange-hued star in the northern constellation of Boötes. It has an apparent visual magnitude of +5.02, which indicates the star is faintly visible to the naked eye. Based upon an annual parallax shift of 3.35 mas as seen from Earth, it is located roughly 970 light years distant from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction of 0.13 due to interstellar dust.

<span class="mw-page-title-main">Upsilon Boötis</span> Star in the constellation Boötes

Upsilon Boötis is a single, orange-hued star in the northern constellation of Boötes. It is a fourth magnitude star that is visible to the naked eye. Based upon an annual parallax shift of 12.38 mas as seen from the Earth, it is located about 263 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −6 km/s.

Chi Boötis, Latinised as χ Boötis, is a single, white-hued star in the northern constellation Boötes, near the eastern constellation border with Corona Borealis. It is faintly visible to the naked eye with an apparent visual magnitude of +5.3. Based upon an annual parallax shift of 13.0 mas as seen from the Earth, it is located about 251 light-years from the Sun. The star is moving closer to the Sun with a radial velocity of −16 km/s.

22 Boötis is a single star in the northern constellation of Boötes, located 319 light years away from the Sun. It has the Bayer designation f Boötis; 22 Boötis is the Flamsteed designation. This object is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.40. It is moving closer to the Earth with a heliocentric radial velocity of −27 km/s.

<span class="mw-page-title-main">44 Boötis</span> Triple star system in the constellation Boötes

44 Boötis or i Boötis is a triple star system in the constellation Boötes. It is approximately 41.6 light years from Earth.

<span class="mw-page-title-main">Sigma Orionis</span> Five-star system in the constellation Orion

Sigma Orionis or Sigma Ori is a multiple star system in the constellation Orion, consisting of the brightest members of a young open cluster. It is found at the eastern end of the belt, south west of Alnitak and west of the Horsehead Nebula which it partially illuminates. The combined brightness of the component stars is magnitude 3.80.

Lambda Geminorum, Latinized from λ Geminorum, is a candidate multiple star system in the constellation Gemini. It is visible to the naked eye at night with a combined apparent visual magnitude of 3.57. The distance to this system is 101 light years based on parallax, and it is drifting closer with a radial velocity of –7.4 km/s. It is a member of what is suspected to be a trailing tidal tail of the Hyades Stream.

<span class="mw-page-title-main">Iota Piscium</span> F-type main sequence star in the constellation Pisces

Iota Piscium is a single, F-type main-sequence star located 45 light years from Earth, in the constellation Pisces. Its spectral type is F7V, which means that it is somewhat larger and brighter than the Sun, but still within the range considered to have the potential for Earth-like planets. It has a surface temperature of about 6,000 to 7,500 K. Iota Piscium is suspected to be a variable star, and was once thought to have one or two stellar companions, but both are line-of-sight coincidences. It displays a far-infrared excess at a wavelength of 70μm, suggesting it is being orbited by a cold debris disk.

HD 5789 and HD 5788 is a pair of stars comprising a binary star system in the northern constellation of Andromeda. Located approximately 151 parsecs (490 ly) away, the primary is a hot, massive blue star with an apparent magnitude of 6.06 while the secondary is slightly smaller and cooler, with an apparent magnitude of 6.76. Both stars are main-sequence stars, meaning that they are currently fusing hydrogen into helium in their cores. As of 2016, the pair had an angular separation of 7.90″ along a position angle of 195°. While both have a similar proper motion and parallax, there's still no proof that the pair is gravitationally bound.

HD 225218 is a quadruple star system in the northern constellation of Andromeda. The primary component, HD 225218 A, is a giant star with a stellar classification of B9III, an apparent magnitude of 6.16, and is a candidate Lambda Boötis star. It has a fainter, magnitude 9.65 companion, HD 225218 B, at an angular separation of 5.2″ along a position angle of 171°. The primary itself has been identified as a binary star system through interferometry, with the two components separated by 0.165″. The pair, HD 225218 Aa and Ab, orbit each other with a period of about 70 years and an eccentricity of 0.515. Component B is likewise a spectroscopic binary.

HD 130917 is a single star in the northern constellation of Boötes. It is an A-type main sequence star with a stellar classification of A4V. At an apparent magnitude of 5.80, it is visible to the naked eye.

16 Camelopardalis is a single star in the northern circumpolar constellation Camelopardalis, located 348 light years away from the Sun as determined from parallax measurements. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 5.28. This object is moving further from the Earth with a heliocentric radial velocity of around 12 km/s.

Sigma Ceti is the Bayer designation for a star in the equatorial constellation of Cetus. With an apparent visual magnitude of 4.78, it can be seen with the naked eye on a dark night. Based upon an annual parallax shift of 37.46 mas, it lies at an estimated distance of 87.1 light years from the Sun. It is a probable astrometric binary star system.

σ Pegasi, Latinised as Sigma Pegasi, is a binary star system in the northern constellation of Pegasus. With a combined apparent visual magnitude of 5.16, it is faintly visible to the naked eye. Based upon an annual parallax shift of 36.66 mas as seen from Earth, the system is located 89 light years distant from the Sun. It has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.524 arcseconds per year.

References

  1. 1 2 3 4 5 6 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.
  2. 1 2 3 4 Elliott, J. E. (October 1974), "Study of delta Scuti variables" (PDF), Astronomical Journal, 79: 1082–1090, Bibcode:1974AJ.....79.1082E, doi:10.1086/111657, hdl: 2152/34447 .
  3. 1 2 Gray, R. O.; et al. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148–2158, Bibcode:2001AJ....121.2148G, doi: 10.1086/319956 .
  4. ↑ Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID   125853869.
  5. ↑ Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv: astro-ph/0112477 , Bibcode:2002ApJS..141..503N, doi:10.1086/340570, S2CID   51814894.
  6. 1 2 Paunzen, E.; et al. (July 2014), "Investigating the possible connection between λ Bootis stars and intermediate Population II type stars", Astronomy & Astrophysics, 567: 8, arXiv: 1406.3936 , Bibcode:2014A&A...567A..67P, doi:10.1051/0004-6361/201423817, S2CID   56332289, A67.
  7. ↑ 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, arXiv: 1501.03154 , Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID   33401607.
  8. 1 2 Luck, R. Earle (March 2018), "Abundances in the Local Region. III. Southern F, G, and K Dwarfs", The Astronomical Journal, 155 (3): 31, Bibcode:2018AJ....155..111L, doi: 10.3847/1538-3881/aaa9b5 , S2CID   125765376, 111.
  9. 1 2 3 4 5 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, S2CID   18993744.. See Table 10.
  10. ↑ Bensby, T.; et al. (2014), "Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood", Astronomy & Astrophysics, 562 (A71): 28, arXiv: 1309.2631 , Bibcode:2014A&A...562A..71B, doi:10.1051/0004-6361/201322631, S2CID   118786105.
  11. 1 2 Martínez-Arnáiz, R.; et al. (September 2010), "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter", Astronomy and Astrophysics, 520: A79, arXiv: 1002.4391 , Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725, S2CID   43455849.
  12. 1 2 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, S2CID   16751327.
  13. 1 2 3 4 Rachford, Brian L.; Foight, Dillon R. (June 2009), "Chromospheric Variability in Early F-Type Stars", The Astrophysical Journal, 698 (1): 786–802, arXiv: 0904.1620 , Bibcode:2009ApJ...698..786R, doi:10.1088/0004-637X/698/1/786, S2CID   693296.
  14. 1 2 "sig Boo", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2021-01-26.
  15. ↑ 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.
  16. ↑ Rodriguez, David R; et al. (2015), "Stellar multiplicity and debris discs: An unbiased sample", Monthly Notices of the Royal Astronomical Society, 449 (3): 3160, arXiv: 1503.01320 , Bibcode:2015MNRAS.449.3160R, doi: 10.1093/mnras/stv483 , S2CID   119237891.
  17. ↑ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv: astro-ph/0412070 , Bibcode:2005AJ....129.1483L, doi:10.1086/427854, S2CID   2603568.
  18. ↑ Gray, Richard O.; Corbally, Christopher (2009), Stellar Spectral Classification, Princeton University Press, Bibcode:2009ssc..book.....G.
  19. ↑ Seach, J. M.; et al. (June 2020), "A magnetic snapshot survey of F-type stars", Monthly Notices of the Royal Astronomical Society, 494 (4): 5682–5703, Bibcode:2020MNRAS.494.5682S, doi: 10.1093/mnras/staa1107 .
  20. ↑ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv: 0910.3229 , Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138, S2CID   119267456.
  21. ↑ Ertel, S.; et al. (May 2018), "The HOSTS Survey—Exozodiacal Dust Measurements for 30 Stars", The Astronomical Journal, 155 (5): 19, arXiv: 1803.11265 , Bibcode:2018AJ....155..194E, doi: 10.3847/1538-3881/aab717 , S2CID   52227431, 194.
  22. ↑ (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.
  23. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 29 日
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