Winnecke 4
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_(noao-m40).jpg){kind=link}
Winnecke 4 (also known as Messier 40 or WNC 4) is an optical double star consisting of two unrelated stars in a northerly zone of the sky, Ursa Major.
The pair were discovered by Charles Messier in 1764 while he was searching for a nebula that had been reported in the area by Johannes Hevelius. Not seeing any nebulae, Messier catalogued this apparent pair instead. In reality, Hevelius (who had made naked eye observations of the sky) had spotted 74 and 75 Ursae Majoris, an unrelated pair of 5th-6th magnitude stars separated by 22 arcminutes, a degree to the East of Winnecke 4, and whose faintness and close separation makes them potentially appear as a single nebulous star to the unaided eye. It is unclear why Messier determined this would correspond to a pair of 9-10th magnitude stars, as Winnecke 4 is far fainter than the naked eye can see even in ideal conditions, although he may have been attempting to catalog it for the sake of pointing out Hevelius's error.[11] The pair were rediscovered by Friedrich August Theodor Winnecke in 1863, and included in the Winnecke Catalogue of Double Stars as number 4. Burnham calls M40 "one of the few real mistakes in the Messier catalog," faulting Messier for including it when all he saw was a double star, not a nebula of any sort.[12]
In 1991 the separation between the components was measured at 51.7′′, an increase since 1764. Data gathered by astronomers Brian Skiff (2001) and Richard L. Nugent (2002) strongly suggested the subject was merely an optical double star rather than a physically connected (binary) system.[6] The A star that seems the brighter is over twice as far as B.[13] Parallax measurements from the Gaia satellite show the two stars, HD 238107 and HD 238108, are at distances of 311 ± 1 parsec (1,013 ± 4 light-years) and 144.2 ± 0.3 parsecs (470 ± 1 light-year) respectively. HD 238108 is itself a genuine binary star, with an 18th magnitude white dwarf companion 5 arcseconds away and a parallax distance of 146.8 ± 2.3 parsecs (479 ± 8 light-years).[citation needed ]
See also
[edit ]References
[edit ]- ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034 . Constellation record for this object at VizieR.
- ^ a b c Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211 . Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940 . S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
- ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211 . Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940 . S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ Ness, M.; Hogg, David W.; Rix, H.-W.; Martig, M.; Pinsonneault, Marc H.; Ho, A. Y. Q. (2016). "Spectroscopic Determination of Masses (And Implied Ages) for Red Giants". The Astrophysical Journal. 823 (2): 114. arXiv:1511.08204 . Bibcode:2016ApJ...823..114N. doi:10.3847/0004-637X/823/2/114 .
- ^ a b c d e Nugent, Richard L (2002). "The Nature of the Double Star M40". Journal of the Royal Astronomical Society of Canada. 96: 63. Bibcode:2002JRASC..96...63N.
- ^ a b c d e f g Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevič, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; de Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv:1904.11302 . Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765 . ISSN 0004-6361.
- ^ 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.
- ^ a b Sit, Tawny; Ness, M. K. (2020). "The Age Distribution of Stars in the Milky Way Bulge". The Astrophysical Journal. 900 (1): 4. arXiv:2006.01158 . Bibcode:2020ApJ...900....4S. doi:10.3847/1538-4357/ab9ff6 . S2CID 219179385.
- ^ a b Stassun, Keivan G.; et al. (2019年10月01日). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694 . Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467 . hdl:1721.1/124721 . ISSN 0004-6256. S2CID 166227927.
- ^ King, Bob (21 May 2025). "The Twisted Path to Unconfounding "Double Star" Messier 40". Sky & Telescope. Retrieved 2 April 2026.
- ^ Robert Burnham (1978). Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System. Courier Corporation. p. 1982. ISBN 978-0-486-23673-5.
- ^ Merrifield, M. R; Gray, M. E; Haran, B (2017). "Gaia Shows that Messier 40 is Definitely Not a Binary Star". The Observatory. 137: 23. arXiv:1612.00834 . Bibcode:2017Obs...137...23M.
External links
[edit ]- Wikimedia Commons logo Media related to Messier 40 at Wikimedia Commons
- SEDS: Messier Object 40
- Messier 40 CCD LRGB image with 2 hrs total exposure
- Sir Patrick Moore; Mike Merrifield; Pete Lawrence. "M40 – Optical Double Star". Deep Sky Videos. Brady Haran.
- Winnecke 4 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
