Delta Sagittae

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δ Sagittae
Sagitta constellation map.svg
Red circle.svg
Location of δ Sagittae (circled)
Observation data
Epoch J2000        Equinox J2000
Constellation Sagitta
Right ascension 19h 47m 23.26653s [1]
Declination +18° 32 03.5203 [1]
Apparent magnitude  (V)+3.82 [2] (3.91 [3] / 6.64) [4]
Characteristics
Spectral type M2II + B9.5V [4]
U−B color index +0.98 [5]
B−V color index +1.40 [5]
Variable type LB? [6]
Astrometry
Radial velocity (Rv)2.5 ± 0.9 [7]  km/s
Proper motion (μ)RA: -6.514 [1]   mas/yr
Dec.: 0.849 [1]   mas/yr
Parallax (π)5.9674 ± 0.2597  mas [8]
Distance 550 ± 20  ly
(168 ± 7  pc)
Absolute magnitude  (MV)−2.58 [9]
Orbit [4]
Period (P)10.15 [10] yr
Semi-major axis (a)0.051″
Eccentricity (e)0.453 [10]
Inclination (i)140.0°
Longitude of the node (Ω)170.2°
Periastron epoch (T)1979.93
Argument of periastron (ω)
(secondary)
257.7°
Details
δ Sge A
Mass 4.073 [10]   M
Radius 223 267 [10]   R
Surface gravity (log g)0.74 ± 0.10 [11]   cgs
Temperature 3,660±170 [12]   K
δ Sge B
Mass 3.611 [10]   M
Radius 3.3 4.7 [10]   R
Luminosity63 [4]   L
Temperature 10000 [4]   K
Other designations
δ  Sagittae, 7  Sagittae, BD+18 4240, CCDM  J19474+1832AB, FK5  743, GC  27391, HD  187076, HIP  97365, HR  7536, IDS  19429+1817 AB, PPM  136976, SAO  105259, WDS  J19474+1832AB
Database references
SIMBAD data

Delta Sagittae (Delta Sge, δ Sagittae, δ Sge) is a binary star in the constellation of Sagitta, with an apparent magnitude of +3.68. The primary component is a red M-type bright giant, and the secondary is a B-type main-sequence star. [2] It is approximately 430 light years from Earth, based on its Gaia Data Release 2 parallax. [1]

A visual band light curve for Delta Sagittae, plotted from data published by Tabur et al. (2009) DeltaSgeLightCurve.png
A visual band light curve for Delta Sagittae, plotted from data published by Tabur et al. (2009)

Delta Sagittae is a spectroscopic binary with a composite spectrum, meaning that light from both stars can be detected. It has an orbital period of about 10 years and an eccentricity of about 0.44. [4] It is also a variable star, with its brightness changing between a maximum of magnitude 3.75 and a minimum of 3.83 in an unpredictable way. [6]

Delta Sagittae is moving through the Galaxy at a speed of 9.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,800 and 35,300 light years from the center of the Galaxy. [14] [ better source needed ]

Naming

In Chinese, 左旗 (Zuǒ Qí), meaning Left Flag , refers to an asterism consisting of δ Sagittae, α Sagittae, β Sagittae, ζ Sagittae, γ Sagittae, 13 Sagittae, 11 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, the Chinese name for δ Sagittae itself is 左旗三 (Zuǒ Qí sān, English: the Third Star of Left Flag.) [15]

Related Research Articles

<span class="mw-page-title-main">Sagitta</span> Constellation in the northern celestial hemisphere

Sagitta is a dim but distinctive constellation in the northern sky. Its name is Latin for 'arrow', not to be confused with the significantly larger constellation Sagittarius 'the archer'. It was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical Union. Although it dates to antiquity, Sagitta has no star brighter than 3rd magnitude and has the third-smallest area of any constellation.

<span class="mw-page-title-main">W Sagittarii</span> Star in the constellation Sagittarius

W Sagittarii is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star.

<span class="mw-page-title-main">Chi Aquarii</span> Star in the constellation Aquarius

Chi Aquarii, Latinized from χ Aquarii, is the Bayer designation of a star in the equatorial constellation of Aquarius. The distance to this star, based upon parallax measurements with a 7% margin of error, is roughly 610 light-years. It is visible to the naked eye with an apparent visual magnitude of about 5.

<span class="mw-page-title-main">28 Andromedae</span> Star in the constellation Andromeda

28 Andromedae is a Delta Scuti variable star in the constellation Andromeda. 28 Andromedae is the Flamsteed designation. It also bears the variable star name GN Andromedae. Its apparent magnitude is 5.214, varying by less than 0.1 magnitudes.

<span class="mw-page-title-main">9 Aurigae</span> Multiple star system in the constellation Auriga

9 Aurigae is a star system in Auriga (constellation). It has an apparent magnitude of about 5, making it visible to the naked eye in many suburban skies. Parallax estimates made by the Hipparcos spacecraft put it at about 86 light-years from the solar system, although individual Gaia Data Release 3 parallaxes place all three components at 88 light years.

<span class="mw-page-title-main">Kappa Boötis</span> Double star in the constellation of Boötes

Kappa Boötis is a double star in the constellation Boötes. It has the traditional name Asellus Tertius and the Flamsteed designation 17 Boötis. The components are separated by an angular distance of 13.5 arcsec, viewable in a small telescope. Kappa Boötis is approximately 155 light years from Earth.

<span class="mw-page-title-main">Iota Canis Majoris</span> Variable star in the constellation Canis Major

Iota Canis Majoris, Latinized from ι Canis Majoris, is a solitary variable supergiant star in the southern constellation of Canis Major. It is visible to the naked eye with an apparent visual magnitude that varies between +4.36 and +4.40. The distance to this star is approximately 2,500 light years based on spectroscopic measurements. It is drifting further away with a radial velocity of +42 km/s.

<span class="mw-page-title-main">Alpha Sagittae</span> Star in the constellation Sagitta

Alpha Sagittae, formally named Sham, is a single star in the northern constellation of Sagitta. Alpha Sagittae is the Bayer designation, which is latinized from α Sagittae and abbreviated Alpha Sge or α Sge. It is visible to the naked eye as a yellow-hued star with an apparent visual magnitude of +4.38. Despite the name, this is not the brightest star in the constellation – that distinction belongs to Gamma Sagittae. Based upon parallax measurements, Alpha Sagittae is approximately 382 light-years from the Sun. It is moving further away from the Earth with a heliocentric radial velocity of 1.7 km/s.

HD 36678 is single star in the northern constellation of Auriga. This star is dimly visible to the naked eye with an apparent visual magnitude of 5.83. It is located at a distance of approximately 840 light years from the Sun based on parallax.

<span class="mw-page-title-main">Delta Delphini</span> Star in the constellation Delphinus

Delta Delphini, Latinized from δ Delphini, is a binary star in the northern constellation of Delphinus. It is visible to the naked eye with an apparent visual magnitude of 4.43. Based upon an annual parallax shift of 14.61 mas as seen from the Earth, the system is located about 223 light years from the Sun.

<span class="mw-page-title-main">Gamma Sagittae</span> Red giant star in the constellation Sagitta

Gamma Sagittae, Latinized from γ Sagittae, is the brightest star in northern constellation of Sagitta. A single star, it is visible to the naked eye with an apparent visual magnitude of +3.47. Based upon an annual parallax shift of 12.62 mas as seen from Earth, it is located about 288 light-years from the Sun. It is moving closer to the Sun with a radial velocity of −34 km/s.

<span class="mw-page-title-main">Epsilon Sagittae</span> Star in the constellation Sagitta

Epsilon Sagittae (ε Sagittae) is a solitary, yellow-hued star in the northern constellation of Sagitta. With an apparent visual magnitude of +5.64 to +5.67, it is faintly visible to the naked eye on a dark night. It is a variable star with a small amplitude of 0.03 magnitudes. Based upon an annual parallax shift of 5.60 mas as seen from Earth, it is located roughly 580 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.1 due to interstellar dust.

<span class="mw-page-title-main">Delta Coronae Borealis</span> Yellow giant star in the constellation Corona Borealis

Delta Coronae Borealis, Latinized from δ Coronae Borealis, is a variable star in the constellation Corona Borealis. Its apparent magnitude varies regularly between apparent magnitude 4.57 and 4.69, and it is around 170 light-years distant.

106 Herculis is a variable star in the northern constellation Hercules. It is visible to the naked eye as a faint, red-hued point of light with a baseline apparent visual magnitude of 4.96. Based on its parallax, it is estimated to lie 383 light-years away from the Sun. The star is moving closer to the Earth with a heliocentric radial velocity of -35 km/s.

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

Sigma Ophiuchi, Latinized from σ Ophiuchi, is a single, orange-hued star in the equatorial constellation Ophiuchus. Its apparent visual magnitude is 4.31, which is bright enough to be faintly visible to the naked eye. The annual parallax shift of 3.62 mas as seen from Earth provides a distance estimate of roughly 900 light years. It is moving closer to the Sun with a radial velocity of −28 km/s.

<span class="mw-page-title-main">QZ Puppis</span> Star in the constellation Puppis

QZ Puppis is a class B2.5V star in the constellation Puppis. Its apparent magnitude is 4.5 and it is approximately 650 light years away based on parallax.

Psi<sup>2</sup> Orionis Spectroscopic binary system in the constellation of Orion

Psi2 Orionis a binary star system in the equatorial constellation of Orion. It has an apparent visual magnitude of 4.6, indicating that it is visible to the naked eye. Based upon an annual parallax shift of 2.87 mass, it is roughly 1,100 light years distant from the Sun.

<span class="mw-page-title-main">V Sagittae</span> Variable star in the constellation Sagitta

V Sagittae or V Sge is a cataclysmic variable in the constellation Sagitta. The system is composed of a main sequence star of about 3.3 solar masses and a white dwarf of about 0.9 solar masses; the fact that the white dwarf is less massive than its companion is highly unusual for a cataclysmic variable, and V Sge is the only super soft X-ray source nonmagnetic cataclysmic variable found so far.

<span class="mw-page-title-main">HD 150193</span> Young binary star system in the constellation Ophiuchus

HD 150193 is a binary star system in the constellation of Ophiuchus. The primary star was identified as a Herbig Ae/Be star with a strong solar wind, losing approximately a tenth of solar mass per million years. It does host a very small debris disk, likely due to disk truncation by the nearby stellar companion. The disk is inclined 38±9° to the plane of sky. It appears to be highly evolved and asymmetric, with indications of flattening and grains growth.

<span class="mw-page-title-main">11 Sagittae</span> Star in the constellation Sagitta

11 Sagittae is a blue in the constellation Sagitta with a spectral type of B9III.

References

  1. 1 2 3 4 5 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 "* del Sge". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 23 February 2017.
  3. Calculated from subtracting magnitudes.
  4. 1 2 3 4 5 6 Eaton, Joel A.; Hartkopf, William I.; McAlister, Harold A.; Mason, Brian D. (1995). "Winds and accretion in delta Sagittae". Astronomical Journal. 109 (4): 1856–1866. Bibcode:1995AJ....109.1856E. doi:10.1086/117412.
  5. 1 2 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  6. 1 2 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
  7. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Bibcode:1953GCRV..C......0W.
  8. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  9. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644.
  10. 1 2 3 4 5 6 Eggleton, Peter P.; Yakut, Kadri (2017). "Models for 60 double-lined binaries containing giants". Monthly Notices of the Royal Astronomical Society. 468 (3): 3533–3556. arXiv: 1611.05041 . doi: 10.1093/mnras/stx598 .
  11. Schröder, K.-P.; Cuntz, M. (2007). "A critical test of empirical mass loss formulas applied to individual giants and supergiants". Astronomy and Astrophysics. 465 (2): 593–601. arXiv: astro-ph/0702172 . Bibcode:2007A&A...465..593S. doi:10.1051/0004-6361:20066633. S2CID   55901104.
  12. Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv: 1905.03744 . Bibcode:2019AJ....158...20M. doi: 10.3847/1538-3881/ab1cbd . S2CID   148571616.
  13. Tabur, V.; Bedding, T. R.; Kiss, L. L.; Moon, T. T.; Szeidl, B.; Kjeldsen, H. (December 2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945–1961. arXiv: 0908.3228 . Bibcode:2009MNRAS.400.1945T. doi: 10.1111/j.1365-2966.2009.15588.x . S2CID   15358380.
  14. "Delta Sagittae (HIP 97365)". Archived from the original on 2013-01-02. Retrieved 2012-09-17.
  15. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日