Sagitta

Not to be confused with the southern constellation of Sagittarius. For other uses, see Sagitta (disambiguation).

Sagitta
Constellation
Sagitta
List of stars in Sagitta
AbbreviationSge[1]
GenitiveSagittae[1]
Pronunciation/səˈdʒɪtə/ or /səˈɡɪtə/ Sagítta,[2]
genitive /səˈdʒɪtiː/
Symbolismthe Arrow[3]
Right ascension18h 57m 21.3919s – 20h 20m 44.8677s[4]
Declination16.0790844° to 21.6436558°[4]
Area79.9[5] sq. deg. (86th)
Main stars4
Bayer/Flamsteed
stars		19
Stars with planets2
Stars brighter than 3.00m0
Stars within 10.00 pc (32.62 ly)2 (GJ 745A/B)
Brightest starγ Sge (3.51m)
Messier objects1
Bordering
constellations		Vulpecula
Hercules
Aquila
Delphinus
Visible at latitudes between +90° and −70°.
Best visible at 21:00 (9 p.m.) during the month of August.

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.

Gamma Sagittae is the constellation's brightest star, with an apparent magnitude of 3.47. It is an aging red giant star 90% as massive as the Sun that has cooled and expanded to a radius 54 times greater than it. Delta, Epsilon, Zeta, and Theta Sagittae are each multiple stars whose components can be seen in small telescopes. V Sagittae is a cataclysmic variable—a binary star system composed of a white dwarf accreting mass of a donor star that is expected to go nova and briefly become the most luminous star in the Milky Way and one of the brightest stars in our sky around the year 2083. Two star systems in Sagitta are known to have Jupiter-like planets, while a third—15 Sagittae—has a brown dwarf companion.

History

Drawing of a dolphin, eagle, archer, and arrow overlaid on a medieval star chart
Sagitta can be seen above Aquila in this plate from Urania's Mirror (1825).

The ancient Greeks called Sagitta Oistos 'the arrow',[3] and it was one of the 48 constellations described by Ptolemy.[6] It was regarded as the weapon that Hercules used to kill the eagle (Aquila) of Jove that perpetually gnawed Prometheus' liver.[7] Sagitta is located beyond the north border of Aquila, the Eagle. An amateur naturalist, polymath Richard Hinckley Allen proposed that the constellation could represent the arrow shot by Hercules towards the adjacent Stymphalian birds (which feature in Hercules' sixth labour) who had claws, beaks, and wings of iron, and who lived on human flesh in the marshes of Arcadia—denoted in the sky by the constellations Aquila the Eagle, Cygnus 'the Swan', and Lyra 'the Vulture'—and still lying between them, whence the title Herculea.[8] Greek scholar Eratosthenes claimed it as the arrow with which Apollo exterminated the Cyclopes.[7] The Romans named it Sagitta.[9] In Arabic, it became al-sahm 'arrow', though this name became Sham and was transferred to Alpha Sagittae only. The Greek name has also been mistranslated as [ὁ istos] Error: {{Lang}}: Non-latn text (pos 1)/Latn script subtag mismatch (help) 'the loom' and thus in Arabic al-nawl. It was also called al-'anaza 'pike/javelin'.[3]

Characteristics

The four brightest stars make up an arrow-shaped asterism located due north of the bright star Altair.[10] Covering 79.9 square degrees and hence 0.194% of the sky, Sagitta ranks 86th of the 88 modern constellations by area. Only Equuleus and Crux are smaller.[5] Sagitta is most readily observed from the late spring to early autumn to northern hemisphere observers, with midnight culmination occurring on 17 July.[11] Its position in the Northern Celestial Hemisphere means that the whole constellation is visible to observers north of 69°S.[5][a] Sagitta is bordered by Vulpecula to the north, Hercules to the west, Aquila to the south, and Delphinus to the east. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "Sge"; American astronomer Henry Norris Russell, who devised the code, had to resort to using the genitive form of the name to come up with a letter to include ('e') that was not in the name of the constellation Sagittarius.[1] The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of twelve segments (illustrated in infobox). In the equatorial coordinate system, the right ascension coordinates of these borders lie between 18h 57.2m and 20h 20.5m , while the declination coordinates are between 16.08° and 21.64°.[4]

Notable features

Stars

See also: List of stars in Sagitta

Celestial cartographer Johann Bayer gave Bayer designations to eight stars, labelling them Alpha to Theta. English astronomer John Flamsteed added the letters x, mistaken as Chi (χ), y and z to 13, 14, and 15 Sagittae in his Catalogus Britannicus. All three were dropped by later astronomers John Bevis and Francis Baily.[12]

Bright stars

Ptolemy saw the constellation's brightest star Gamma Sagittae as marking the arrow's head,[6] while Bayer saw Gamma, Eta, and Theta as depicting the arrow's shaft.[12] Gamma Sagittae is a red giant of spectral type M0 III,[13] and magnitude 3.47. It lies at a distance of 258±4 light-years from Earth.[14] With around 90% of the Sun's mass,[15][16] it has a radius 54 times that of the Sun and is 575 times as bright. It is most likely on the red-giant branch of its evolutionary lifespan, having exhausted its core hydrogen and now burning it in a surrounding shell.[15]

Delta Sagittae is the second-brightest star in the constellation and is a binary. Delta and Zeta depicted the spike according to Bayer.[17] The Delta Sagittae system is composed of a red supergiant of spectral type M2 II[18] that has 3.9 times the Sun's mass and 152 times its radius and a blue-white B9.5V[18] main sequence star that is 2.9 times as massive as the Sun. The two orbit each other every ten years.[18] Zeta Sagittae is a triple star system,[19] approximately 326 light-years from Earth. The primary and secondary are A-type stars.[20][21]

In his Uranometria, Bayer depicted Alpha, Beta, and Epsilon Sagittae as the fins of the arrow.[17] Also known as Sham, Alpha is a yellow bright giant star of spectral class G1 II with an apparent magnitude of 4.38, which lies at a distance of 382±8 light-years from Earth.[22] Four times as massive as the Sun, it has swollen and brightened to 21 times the Sun's radius and 340 times its luminosity.[23][24] Also of magnitude 4.38, Beta is a G-type giant located 420±10 light-years distant from Earth.[25] Estimated to be around 129 million years old, it is 4.33 times as massive as the Sun,[26] and has expanded to roughly 27 times its radius.[23] Epsilon Sagittae is a double star whose component stars can be seen in a small telescope.[27] With an apparent magnitude of 5.77,[28] the main star is a 331-million-year-old yellow giant of spectral type G8 III around 3.09 times as massive as the Sun,[29] that has swollen to 18.37+0.65
−0.88 its radius.[30] It is 580±10 light-years distant.[30] The visual companion of magnitude 8.35 is 87.4 arcseconds distant,[28] but is an unrelated blue supergiant around 7,000 light-years distant from Earth.[31]

Eta Sagittae is an orange giant of spectral class K2 III[32] with a magnitude of 5.09.[33] Located 155.9±0.9 light-years from Earth, it has a 61.1% chance of being a member of the Hyades–Pleiades stream of stars that share a common motion through space.[34] Theta Sagittae is a double star system, with components 12 arcseconds apart visible in a small telescope.[27] At magnitude 6.5, the brighter is a yellow-white main sequence star of spectral type F3 V,[35] located 146.1±0.2 light-years from Earth.[36] The 8.8-magnitude fainter companion is a main sequence star of spectral type G5 V. A 7.4-magnitude orange giant of spectral type K2 III is also visible 91″ from the binary pair,[35] located 842±9 light-years away.[37]

Variable stars

James Webb Space Telescope image of WR 124 in Sagitta. NIRCam and MIRI composite

Variable stars are popular targets for amateur astronomers, their observations providing valuable contributions to understanding star behaviour.[38] R Sagittae is a member of the rare RV Tauri variable class of star. It ranges in magnitude from 8.2 to 10.4.[39] It is around 8,100 light-years distant.[40] It has a radius 61.2+12.4
−9.9 times that of the Sun, and is 2,329+744
−638 as luminous, yet most likely is less massive than the Sun. An aging star, it has moved on from the asymptotic giant branch of stellar evolution and is on its way to becoming a planetary nebula.[41] FG Sagittae is a "born again" star, a highly luminous star around 4,000 light-years distant from Earth.[42] It reignited fusion of a helium shell shortly before becoming a white dwarf, and has expanded first to a blue supergiant and then to a K-class supergiant in less than 100 years.[43] It is surrounded by a faint (visual magnitude 23) planetary nebula, Henize 1–5, that formed when FG Sagittae first left the asymptotic giant branch.[44]

S Sagittae is a classical Cepheid that varies from magnitude 5.24 to 6.04 every 8.38 days. It is a yellow-white supergiant that pulsates between spectral types F6 Ib and G5 Ib.[45] Around 6 or 7 times as massive and 3,500 times as luminous as the Sun,[46] it is located around 5,100 light-years from Earth.[47] HD 183143 is a remote highly luminous star around 7,900 light-years away,[48] that has been classified as a blue hypergiant.[49] Infrared bands of ionised buckminsterfullerene molecules have also been found in its spectrum.[50] WR 124 is a Wolf–Rayet star moving at great speed surrounded by a nebula of ejected gas.[51]

U Sagittae is an eclipsing binary that varies between magnitudes 6.6 and 9.2 over 3.4 days, making it a suitable target for enthusiasts with small telescopes.[10] There are two component stars—a blue-white star of spectral type B8 V and an ageing star that has cooled and expanded into a yellow subgiant of spectral type G4 III-IV. They orbit each other close enough that the cooler subgiant has filled its Roche lobe and is passing material to the hotter star, and hence it is a semidetached binary system.[52] The system is 900±10 light-years distant.[53] Near U Sagittae is X Sagittae, a semiregular variable ranging between magnitudes 7.9 and 8.4 over 196 days.[10] A carbon star, X Sagittae has a surface temperature of 2,576 K.[54]

Located near 18 Sagittae is V Sagittae, the prototype of the V Sagittae variables, cataclysmic variables that are also super soft X-ray sources.[39] It is expected to become a luminous red nova when the two stars merge around the year 2083, and briefly become the most luminous star in the Milky Way and one of the brightest stars in Earth's sky.[55][56] WZ Sagittae is another cataclysmic variable, composed of a white dwarf that has about 85% the mass of the Sun, and low-mass star companion that has been calculated to be a brown dwarf of spectral class L2 that is only 8% as massive as the Sun.[57] Normally a faint object dimmer than magnitude 15, it flared up in 1913, 1946 and 1978 to be visible in binoculars.[10] The black widow pulsar (B1957+20) is the second millisecond pulsar ever discovered.[58] It is a massive neutron star that is ablating its brown dwarf-sized companion which causes the pulsar's radio signals to attenuate as they pass through the outflowing material.[59]

Stars with exoplanets

Several hundred stars of different brightnesses and colours scattered on a black background
Messier 71 globular cluster

HD 231701 is a yellow-white main sequence star hotter and larger than the Sun, with a Jupiter-like planet that was discovered in 2007 by the radial velocity technique. The planet orbits at a distance of 0.57 AU from the star with a period of 141.6 days.[60] It has a mass of at least 1.13 Jupiter masses.[61]

HAT-P-34 is a star 1.392±0.047 times as massive as the Sun with 1.535+0.135
−0.102 times its radius and 3.63+0.75
−0.51 times its luminosity. With an apparent magnitude of 10.4,[62] it is 819±9 light-years distant.[63] A planet 3.328±0.211 times as massive as Jupiter was discovered transiting it in 2012. With a period of 5.45 days and a distance of 0.06 AU from its star, it has an estimated surface temperature of 1,520±60 K.[62]

15 Sagittae is a solar analog—a star similar to the Sun, with 1.08±0.04 times its mass, 1.115±0.021 times its radius and 1.338±0.03 times its luminosity. It has an apparent magnitude of 5.80.[64] It has an L4 brown dwarf substellar companion that is around the same size as Jupiter but 69 times as massive with a surface temperature of between 1,510 and 1,850 K, taking around 73.3 years to complete an orbit around the star.[65] The system is estimated to be 2.5±1.8 billion years old.[65]

Deep-sky objects

The band of the Milky Way and the Great Rift within it pass though Sagitta, with Alpha, Beta and Epsilon Sagittae marking the Rift's border.[66] Located between Beta and Gamma Sagittae is Messier 71,[10] a very loose globular cluster mistaken for some time for a dense open cluster.[67] At a distance of about 13,000 light-years from Earth,[68] it was first discovered by the French astronomer Philippe Loys de Chéseaux in the year 1745 or 1746.[67] The loose globular cluster has a mass of around 53,000 M☉ and a luminosity of approximately 19,000 L☉.[69]

There are two notable planetary nebulae in Sagitta: NGC 6886 is composed of a hot central post-AGB star that has 55% of the Sun's mass yet 2,700±850 times its luminosity, with a surface temperature of 142,000 K, and surrounding nebula estimated to have been expanding for between 1,280 and 1,600 years,[70] The nebula was discovered by Ralph Copeland in 1884.[71] The Necklace Nebula—originally a close binary, one component of which swallowed the other as it expanded to become a giant star. The smaller star remained in orbit inside the larger, whose rotation speed increased greatly, resulting in it flinging its outer layers off into space, forming a ring with knots of bright gas formed from clumps of stellar material.[72] It was discovered in 2005 and is around 2 light-years wide.[73][72] It has a size of 0.35′.[74] Both nebulae are around 15,000 light-years from Earth.[70][72]

See also

Notes

  1. ^ While parts of the constellation technically rise above the horizon to observers between the 69°S and 73°S, stars within a few degrees of the horizon are to all intents and purposes unobservable.[5]

References

  1. ^ a b c Russell, Henry Norris (1922). "The New International Symbols for the Constellations". Popular Astronomy. 30: 469. Bibcode:1922PA.....30..469R.
  2. ^ "Sagitta". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 2021-04-15.
  3. ^ a b c Kunitzsch, Paul (2002). "Albumasariana" (PDF). Annali dell'Università degli studi di Napoli "L'Orientale". 62. Rivista del Dipartimento di Studi Asiatici e del Dipartimento di Studi e Ricerche su Africa e Paesi Arabi: 4. ISSN 0393-3180.
  4. ^ a b c "Sagitta, Constellation Boundary". International Astronomical Union. Retrieved 20 October 2020.
  5. ^ a b c d Ridpath, Ian. "Constellations: Lacerta–Vulpecula". Star Tales. Retrieved 22 May 2015.
  6. ^ a b Ridpath, Ian. "Sagitta". Star Tales. Retrieved 22 May 2015.
  7. ^ a b Hyginus. "Astronomica". Theoi Project. Translated by Mary Grant. Retrieved 31 January 2020.
  8. ^ Allen, Richard Hinckley (1963) [1899]. Star-Names and Their Meanings. New York: Dover Publications. pp. 349–351. ISBN 978-0-486-21079-7.
  9. ^ Bagnall, Philip M. (2012). The Star Atlas Companion: What You Need to Know about the Constellations. New York: Springer. pp. 386–389. ISBN 978-1-4614-0830-7. OCLC 794225463.
  10. ^ a b c d e Moore, Patrick (2005). The Observer's Year: 366 Nights in the Universe. New York: Springer Science & Business Media. p. 10. ISBN 978-1-85233-884-8.
  11. ^ Thompson, Robert Bruce; Barbara Fritchman (2007). Illustrated Guide to Astronomical Wonders: From Novice to Master Observer. Sebastopol, California: O'Reilly Media, Inc. p. 392. ISBN 978-0-596-52685-6.
  12. ^ a b Wagman, Morton (2003). Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others. Blacksburg, Virginia: The McDonald & Woodward Publishing Company. pp. 266–267, 515. ISBN 978-0-939923-78-6.
  13. ^ Strassmeier, K. G.; Ilyin, I.; Weber, M. (2018). "PEPSI deep spectra. II. Gaia benchmark stars and other M-K standards". Astronomy and Astrophysics. 612: A45. arXiv:1712.06967. Bibcode:2018A&A...612A..45S. doi:10.1051/0004-6361/201731633. S2CID 119244142.
  14. ^ van Leeuwen, F. (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.
  15. ^ a b Stock, Stephan; Reffert, Sabine; Quirrenbach, Andreas; Hauschildt, P. (2018). "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search". Astronomy and Astrophysics. 616: A33. arXiv:1805.04094. Bibcode:2018A&A...616A..33S. doi:10.1051/0004-6361/201833111. S2CID 119361866.
  16. ^ Neilson, Hilding R.; Lester, John B. (2008). "Determining parameters of cool giant stars by modeling spectrophotometric and interferometric observations using the SAtlas program". Astronomy and Astrophysics. 490 (2): 807–10. arXiv:0809.1875. Bibcode:2008A&A...490..807N. doi:10.1051/0004-6361:200810627. S2CID 1586125.
  17. ^ a b Wagman 2003, p. 515.
  18. ^ a b c 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.
  19. ^ 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.
  20. ^ Christy, James W.; Walker, R. L. Jr. (October 1969), "MK Classification of 142 Visual Binaries", Publications of the Astronomical Society of the Pacific, 81 (482): 643, Bibcode:1969PASP...81..643C, doi:10.1086/128831.
  21. ^ Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
  22. ^ 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.
  23. ^ a b Van Belle, G. T.; Creech-Eakman, M. J.; Hart, A. (2009). "Supergiant temperatures and linear radii from near-infrared interferometry". Monthly Notices of the Royal Astronomical Society. 394 (4): 1925. arXiv:0811.4239. Bibcode:2009MNRAS.394.1925V. doi:10.1111/j.1365-2966.2008.14146.x. S2CID 118372600.
  24. ^ Kaler, James B. "Sham". Stars. University of Illinois. Retrieved 22 May 2015.
  25. ^ 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.
  26. ^ Liu, Y. J.; et al. (2014). "The Lithium Abundances of a Large Sample of Red Giants". The Astrophysical Journal. 785 (2): 12. arXiv:1404.1687. Bibcode:2014ApJ...785...94L. doi:10.1088/0004-637X/785/2/94. S2CID 119226316. 94.
  27. ^ a b Consolmagno, Guy (2019) [1989]. Turn Left at Orion: Hundreds of Night Sky Objects to See in a Home Telescope – and How to Find Them. Cambridge, United Kingdom: Cambridge University Press. p. 138. ISBN 978-1-108-45756-9.
  28. ^ a b Mason, B. D.; Wycoff, G. L.; Hartkopf, W. I.; Douglass, G. G.; Worley, C. E. (2014). "The Washington Visual Double Star Catalog". Nature. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  29. ^ Takeda, Yoichi; Tajitsu, Akito (2014). "Spectroscopic study on the beryllium abundances of red giant stars". Publications of the Astronomical Society of Japan. 66 (5): 91. arXiv:1406.7066. Bibcode:2014PASJ...66...91T. doi:10.1093/pasj/psu066. S2CID 119283677.
  30. ^ a b 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.
  31. ^ 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.
  32. ^ Roman, Nancy G. (July 1952), "The Spectra of the Bright Stars of Types F5-K5", Astrophysical Journal, 116: 122, Bibcode:1952ApJ...116..122R, doi:10.1086/145598.
  33. ^ Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133 (4): 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475.
  34. ^ Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165–186. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
  35. ^ a b Abt, Helmut A. (1985). "Visual multiples. VIII. 1000 MK types". The Astrophysical Journal Supplement Series. 59: 95–112. Bibcode:1985ApJS...59...95A. doi:10.1086/191064.
  36. ^ 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.
  37. ^ 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.
  38. ^ Tooke, Owen (24 August 2017). "Variables: What Are They and Why Observe Them?". AAVSO. Retrieved 14 October 2020.
  39. ^ a b Levy, David H. (1998). Observing Variable Stars: A Guide for the Beginner. Cambridge, United Kingdom: Cambridge University Press. pp. 152–153. ISBN 978-0-521-62755-9.
  40. ^ 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.
  41. ^ Bódi, A.; Kiss, L. L. (2019). "Physical Properties of Galactic RV Tauri Stars from Gaia DR2 Data". The Astrophysical Journal. 872 (1): 60. arXiv:1901.01409. Bibcode:2019ApJ...872...60B. doi:10.3847/1538-4357/aafc24. S2CID 119099605.
  42. ^ 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.
  43. ^ Jurcsik, Johanna; Montesinos, Benjamín. (1999). "The remarkable evolution of the post-AGB star FG Sge" (PDF). New Astronomy Reviews. 43 (6): 415. Bibcode:1999NewAR..43..415J. doi:10.1016/S1387-6473(99)00098-6.
  44. ^ Rosenbush, A. É.; Efimov, Yu. S. (2015). "Photometry, Spectrometry, and Polarimetry of FG Sge in the Active State". Astrophysics. 58 (1): 46. Bibcode:2015Ap.....58...46R. doi:10.1007/s10511-015-9365-x. S2CID 121128187.
  45. ^ Watson, Christopher (4 January 2010). "S Sagittae". AAVSO. Retrieved 22 May 2015.
  46. ^ Kaler, James B. (4 October 2013). "S Sagittae". Stars. University of Illinois. Retrieved 22 May 2015.
  47. ^ 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.
  48. ^ 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.
  49. ^ Chentsov, E. L. (2004). "HD 183143: A Hypergiant". Astronomy Letters. 30 (5): 325–331. Bibcode:2004AstL...30..325C. doi:10.1134/1.1738155. S2CID 121435951.
  50. ^ Walker, G. A. H.; Bohlender, D. A.; Maier, J. P.; Campbell, E. K. (2015). "Identification of More Interstellar C60+ Bands". The Astrophysical Journal Letters. 812 (1): L8. arXiv:1509.06818. Bibcode:2015ApJ...812L...8W. doi:10.1088/2041-8205/812/1/L8. S2CID 118598331.
  51. ^ Crowther, Paul A.; Pasquali, A.; De Marco, Orsola; Schmutz, W.; Hillier, D. J.; De Koter, A. (1999). "Wolf–Rayet nebulae as tracers of stellar ionizing fluxes. I. M1-67". Astronomy and Astrophysics. 350: 1007. arXiv:astro-ph/9908200. Bibcode:1999A&A...350.1007C.
  52. ^ Malkov, Oleg Yu (2020). "Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes". Monthly Notices of the Royal Astronomical Society. 491 (4): 5489–5497. Bibcode:2020MNRAS.491.5489M. doi:10.1093/mnras/stz3363.
  53. ^ 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.
  54. ^ Taranova, O.G.; Shenavrin, V. I. (2004). "JHKLM Photometry for Carbon Stars". Astronomy Letters. 30 (8): 605–622. Bibcode:2004AstL...30..549T. doi:10.1134/1.1784497. S2CID 119984131.
  55. ^ Lavalle, Mimi (7 January 2020). "Binary star V Sagittae to explode as very bright nova by century's end". phys.org. Retrieved 9 January 2020.
  56. ^ "There will be a new brightest star in the sky, when it explodes in about 60 years". CNN. 8 Jan 2020. Archived from the original on 13 January 2020. Retrieved 9 January 2020.
  57. ^ Steeghs, Danny; Howell, Steve B.; Knigge, Christian; Gänsicke, Boris T.; Sion, Edward M.; Welsh, William F. (September 2007). "Dynamical Constraints on the Component Masses of the Cataclysmic Variable WZ Sagittae". The Astrophysical Journal. 667 (1): 442–447. arXiv:0706.0987. Bibcode:2007ApJ...667..442S. doi:10.1086/520702. S2CID 209833493.
  58. ^ Fruchter, A. S.; Stinebring, D. R.; Taylor, J. H. (1988). "A millisecond pulsar in an eclipsing binary". Nature. 333 (6170): 237–239. Bibcode:1988Natur.333..237F. doi:10.1038/333237a0. S2CID 4337525.
  59. ^ "B1957+20: A Cocoon Found Inside the Black Widow's Web". Chandra. Retrieved 23 October 2020.
  60. ^ Fischer, Debra A.; Vogt, Steven S.; Marcy, Geoffrey W.; Butler, R. Paul; Sato, Bun'ei; Henry, Gregory W.; Robinson, Sarah; Laughlin, Gregory; Ida, Shigeru (2007). "Five Intermediate-Period Planets from the N2K Sample". The Astrophysical Journal. 669 (2): 1336–1344. arXiv:0704.1191. Bibcode:2007ApJ...669.1336F. doi:10.1086/521869. S2CID 7774321.
  61. ^ Ment, Kristo; et al. (2018). "Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810". The Astronomical Journal. 156 (5). 213. arXiv:1809.01228. Bibcode:2018AJ....156..213M. doi:10.3847/1538-3881/aae1f5. S2CID 119243619.
  62. ^ a b Bakos, G. Á.; Hartman, J. D.; Torres, G.; Béky, B.; Latham, D. W.; Buchhave, L. A.; Csubry, Z.; Kovács, Géza; Bieryla, A.; Quinn, S.; Szklenár, T.; Esquerdo, G. A.; Shporer, A.; Noyes, R. W.; Fischer, D. A.; Johnson, J. A.; Howard, A. W.; Marcy, G. W.; Sato, B.; Penev, K.; Everett, M.; Sasselov, D. D.; Fűrész, G.; Stefanik, R. P.; Lázár, J.; Papp, I.; Sári, P. (2012). "HAT-P-34b – HAT-P-37b: Four Transiting Planets More Massive Than Jupiter Orbiting Moderately Bright Stars". The Astronomical Journal. 144 (1): 19–32. arXiv:1201.0659. Bibcode:2012AJ....144...19B. doi:10.1088/0004-6256/144/1/19. S2CID 119291677.
  63. ^ 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.
  64. ^ 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.
  65. ^ a b Crepp, Justin R.; Johnson, John Asher; Fischer, Debra A.; Howard, Andrew W.; Marcy, Geoffrey W.; Wright, Jason T.; Isaacson, Howard; Boyajian, Tabetha; von Braun, Kaspar; Hillenbrand, Lynne A.; Hinkley, Sasha; Carpenter, John M.; Brewer, John M. (2012). "The Dynamical Mass and Three-Dimensional Orbit of HR7672B: A Benchmark Brown Dwarf with High Eccentricity". The Astrophysical Journal. 751 (2): 14. arXiv:1112.1725. Bibcode:2012ApJ...751...97C. doi:10.1088/0004-637X/751/2/97. S2CID 16113054. 97.
  66. ^ Crossen, Craig; Rhemann, Gerald (2012) [2004]. Sky Vistas: Astronomy for Binoculars and Richest-Field Telescopes. New York: Springer. p. 150. ISBN 978-3-709-10626-6.
  67. ^ a b Thompson, Robert Bruce; Thompson, Barbara Fritchman (2007). Illustrated Guide to Astronomical Wonders: From Novice to Master Observer. North Sebastopol, California: O'Reilly Media. p. 394. ISBN 978-0-596-52685-6.
  68. ^ Inglis, Mike (2017). Astronomy of the Milky Way: The Observer's Guide to the Northern Sky. New York: Springer. pp. 83–89. ISBN 978-3-319-49082-3.
  69. ^ Dalgleish, H.; Kamann, S.; Usher, C.; Baumgardt, H.; Bastian, N.; Veitch-Michaelis, J.; Bellini, A.; Martocchia, S.; Da Costa, G. S.; Mackey, D.; Bellstedt, S.; Pastorello, N.; Cerulo, P. (March 2020). "The WAGGS project-III. Discrepant mass-to-light ratios of Galactic globular clusters at high metallicity". Monthly Notices of the Royal Astronomical Society. 492 (3): 3859–3871. arXiv:2001.01810. Bibcode:2020MNRAS.492.3859D. doi:10.1093/mnras/staa091.
  70. ^ a b Schönberner, D.; Balick, B.; Jacob, R. (2018). "Expansion patterns and parallaxes for planetary nebulae". Astronomy & Astrophysics. 609: A126. Bibcode:2018A&A...609A.126S. doi:10.1051/0004-6361/201731788.
  71. ^ Seligman, Courtney. "NGC Objects: NGC 6850 - 6899". Retrieved 22 August 2015.
  72. ^ a b c Weaver, Donna; Villard, Ray (11 August 2011). "Hubble Offers a Dazzling 'Necklace'" (Press release). NASA. Space Telescope Science Institute. Retrieved 20 October 2020.
  73. ^ Hubble Offers a Dazzling View of the 'Necklace' Nebula, news release STScI-2011-24 dated August 11, 2011, from Space Telescope Science Institute
  74. ^ Sabin, L.; et al. (October 2014). "First release of the IPHAS catalogue of new extended planetary nebulae". Monthly Notices of the Royal Astronomical Society. 443 (4): 3388–3401. arXiv:1407.0109. Bibcode:2014MNRAS.443.3388S. doi:10.1093/mnras/stu1404.
Wikimedia Commons has media related to Sagitta.

Read other articles:

Epiphyllum

Epiphyllum Epiphyllum chrysocardium Klasifikasi ilmiah Domain: Eukaryota Kerajaan: Plantae Divisi: Magnoliophyta Kelas: Magnoliopsida Ordo: Caryophyllales Famili: Cactaceae Subfamili: Cactoideae Tribus: Hylocereeae Genus: EpiphyllumHaw. Spesies tipe Epiphyllum phyllanthus Spesies Lihat teks Sinonim[1] Phyllocereus Miq. Marniera Backeb. Phyllocactus Link Epiphyllum (/ˌɛpɪˈfɪləm/;[2] berasal dari bahasa yunani yang berarti di atas daun) adalah genus tumbuhan epifit dalam ...

 

 

Johnstown (Pennsylvania)

Questa voce sull'argomento centri abitati della Pennsylvania è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Johnstowncity(EN) Johnstown, Pennsylvania Johnstown – VedutaLa stazione centrale LocalizzazioneStato Stati Uniti Stato federato Pennsylvania ConteaCambria AmministrazioneSindacoTom Trigona TerritorioCoordinate40°19′22.08″N 78°55′14.88″W / 40.3228°N 78.9208°...

 

 

الدوري اللبناني الدرجة الثانية 2006–07

الدوري اللبناني الدرجة الثانية السلسلة الدوري اللبناني الدرجة الثانية  الموسم 2006–07 البلد لبنان  الفائز شباب الساحل صاعدون الراسينغ بيروت الدوري اللبناني الممتاز هابطون الراسينغ بيروت Al-Tadamon Nabatieh الدوري اللبناني الدرجة الثانية 2005–06 الدوري اللبناني - الدرجة الثاني�...

Blackacre

In law, name for a fictitious estate Property law Part of the common law series Types Personal property Community property Real property Unowned property Acquisition Gift Adverse possession Deed Conquest Discovery Accession Lost, mislaid, and abandoned property Treasure trove Bailment License Alienation Estates in land Allodial title Fee simple Fee tail Life estate Defeasible estate Future interest remainder Concurrent estate Leasehold estate Condominiums Real estate Land tenure Conveyancing ...

 

 

Korintus

KorintusΚόρινθοςKórinthos Kuil Apollo di Korintus Kuno Lambang Korintus Letak Koordinat 37°56′N 22°56′E / 37.933°N 22.933°E / 37.933; 22.933Koordinat: 37°56′N 22°56′E / 37.933°N 22.933°E / 37.933; 22.933 Zona waktu: EET/EEST (UTC+2/3) Ketinggian (min-max): 0 - 10 m (0 - 33 ft) Pemerintah Negara: Yunani Periferal: Peloponnesus Prefektur: Korinthia Statistik penduduk (pada 2001[1]...

 

 

Dolenice

Cet article est une ébauche concernant une localité tchèque. Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants. Dolenice   Administration Pays Tchéquie Région Moravie-du-Sud District Znojmo Région historique Moravie Maire Viktor Antl Code postal 671 78 Démographie Population 140 hab. (2020) Densité 31 hab./km2 Géographie Coordonnées 48° 54′ 31″ nord, 16° 21′ ...

Protection dorsale

Pour les articles homonymes, voir dorsale. Dorsale homologuée EN 1621-2 de niveau 2. Une protection dorsale ou dorsale est une coque protégeant le dos et la colonne vertébrale en cas de choc, la colonne pouvant souffrir de séquelles irrémédiables en cas d'accident. La dorsale peut être utilisée dans les sports risqués, en amateur ou en compétition, par exemple elle est obligatoire en compétition motocycliste sur circuit. Elle se compose de mousse durcie ou plastique et peut être ...

 

 

Ahmad Muhdlor Ali

Ahmad Muhdlor AliPotret resmi Ahmad Muhdlor Ali sebagai Bupati Sidoarjo Bupati Sidoarjo ke-12PetahanaMulai menjabat 26 Februari 2021 (2021-02-26)PresidenJoko WidodoGubernurKhofifah Indar ParawansaAdhy Karyono (Pj.)WakilSubandiPendahuluSaiful Ilah Hudiyono (Penjabat)PenggantiPetahana Informasi pribadiLahir11 Februari 1991 (umur 33)Tulangan, SidoarjoPartai politikIndependenAlma materUniversitas AirlanggaPekerjaanPolitikusAkademikusDikenal karenaSekretaris GP Ansor SidoarjoSunt...

 

 

British Sugar

British food company British Sugar plcFormerlyBritish Sugar Corporation Limited (1936–1982)[1]Company typeSubsidiaryIndustrySugar beet processingPredecessorAnglo-Scottish Beet Sugar Corporation Founded1936HeadquartersPeterborough, England, United KingdomNumber of locations5Area servedUnited KingdomKey peopleKeith Packer (managing director)ProductsSugarBioethanolAnimal feedTopsoilSoil conditionersRevenue £714.1 million (2021)[2]Operating income £59.8 million (2021)[...

Constantine V

Byzantine Emperor from 741 to 775 This article is about the emperor. For the religious figure, see Constantine V of Constantinople. Constantine VEmperor of the RomansSolidus of Constantine V.Byzantine emperorReign18 June 741 – 14 September 775Coronation31 March 720[1]PredecessorLeo III the IsaurianSuccessorLeo IV the KhazarRival emperorsArtabasdos (741–43)Nikephoros (741–43)BornJuly 718[2]Constantinople(now Istanbul, Turkey)Died14 September 775 (aged 57)WivesTzitzak (Ire...

 

 

Ethiopia–Italy relations

Bilateral relationsEthiopian-Italian relations Ethiopia Italy Ethiopia–Italy relations are the current and historical relations between Ethiopia and Italy. History Modern Italian colonial ambitions into Ethiopia began in the 1880s.[1] This was eventually followed by the Italo-Ethiopian War of 1887–1889, in which Italy occupied the Ethiopian territory in present-day Eritrea, founding the colony of Italian Eritrea. Years later, the disputed Treaty of Wuchale led to the First Italo-E...

 

 

Египтопитек

† Египтопитек Реконструкция внешнего вида египтопитека Научная классификация Домен:ЭукариотыЦарство:ЖивотныеПодцарство:ЭуметазоиБез ранга:Двусторонне-симметричныеБез ранга:ВторичноротыеТип:ХордовыеПодтип:ПозвоночныеИнфратип:ЧелюстноротыеНадкласс:Четвероно...

Two and a Half Men

Two and a Half MenPembuatChuck LorreLee AronsohnPengembangWarner Brothers TelevisionPemeranCharlie SheenJon CryerAngus T. JonesMarin HinkleHolland TaylorMelanie LynskeyConchata FerrellRyan StilesApril BowlbyPenggubah lagu temaChuck LorreNegara asalAmerika SerikatJmlh. musim12Jmlh. episode262ProduksiLokasi produksiMalibu, California, USAPengaturan kameraMulti-cameraDurasi22 menitRilis asliJaringanCBSFormat gambar480i (SDTV),1080i (HDTV)Rilis22 September 2003 –19 Februari 2015 Two and a...

 

 

Joiselle

JoisellecomuneJoiselle – Veduta LocalizzazioneStato Francia RegioneGrand Est Dipartimento Marna ArrondissementÉpernay CantoneSézanne-Brie et Champagne TerritorioCoordinate48°46′N 3°31′E / 48.766667°N 3.516667°E48.766667; 3.516667 (Joiselle)Coordinate: 48°46′N 3°31′E / 48.766667°N 3.516667°E48.766667; 3.516667 (Joiselle) Superficie10 km² Abitanti89[1] (2009) Densità8,9 ab./km² Altre informazioniCod. postale51310 ...

 

 

2020年夏季奧林匹克運動會波蘭代表團

2020年夏季奥林匹克运动会波兰代表團波兰国旗IOC編碼POLNOC波蘭奧林匹克委員會網站olimpijski.pl（英文）（波兰文）2020年夏季奥林匹克运动会（東京）2021年7月23日至8月8日（受2019冠状病毒病疫情影响推迟，但仍保留原定名称）運動員206參賽項目24个大项旗手开幕式：帕维尔·科热尼奥夫斯基（游泳）和马娅·沃什乔夫斯卡（自行车）[1]闭幕式：卡罗利娜·纳亚（皮划艇）&#...

الخطوط الجوية الإسكندنافية الرحلة 347

الخطوط الجوية الإسكندنافية الرحلة 347 ملخص الحادث التاريخ 3 نوفمبر 1994 نوع الحادث اختطاف الموقع مطار أوسلو-غاردرموين ، أوسلو، النرويج الركاب 122 الطاقم 6 الجرحى 0 الوفيات 0 الناجون 128 (جميعهم) النوع ماكدونل دوغلاس إم دي-80 المالك الخطوط الجوية الإسكندنافية بداية الرحلة مطار بارد...

 

 

كاترين الإسكندرانية

كاترين الإسكندرانية معلومات شخصية الميلاد 287الإسكندرية الوفاة 305الإسكندرية سبب الوفاة قطع الرأس  مواطنة روما القديمة  الحياة العملية المهنة مبشرة  تعديل مصدري - تعديل   كاترينا الإسكندرانية، لوحة لكارلو كريفيلي كاترينا الإسكندرانية (باليونانية: ἡ Ἁγία Αἰκατε...

 

 

Cyclura cychlura inornata

Subspecies of lizard Cyclura cychlura inornata Cyclura cychlura inornata Conservation status Critically Endangered  (IUCN 3.1) [1] Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Reptilia Order: Squamata Suborder: Iguania Family: Iguanidae Genus: Cyclura Species: C. cychlura Subspecies: C. c. inornata Trinomial name Cyclura cychlura inornata(Barbour & Noble, 1916)[1][2] Synonyms[1] Cyclura inornata B...

Tokachi District, Hokkaido

District in Hokkaidō, Japan The area of Tokachi District in Tokachi SubprefectureThis article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Tokachi District, Hokkaido – news · newspapers · books · scholar · JSTOR (October 2023) (Learn how and when to remove this message) Tokachi District (十勝郡, Tokachi-gun) is a ...

 

 

National Historic Landmark

Designation by the US government Independence National Historical Park in Philadelphia, one of the nation's most visited National Historic Landmark Districts Navajo Nation Council Chamber, the seat of government for Navajo Nation in Window Rock, Arizona A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Only some 2,500, or roughly three percent, of ove...