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39 Cygni — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/39_Cygni
License (as archived): CC-BY-SA-4.0
Archived: 2026-11-06T14:58:19.685Z
SHA-256 of the archived text: 8ea7af5c677a2dc56985b301d1a1839c3e3afe76901ce2f773d6f3d2fff1c08f
Stable URL of this page: https://metraipolis.com/documento/dc_e2f24aba4fef

How to cite

39 Cygni — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/39_Cygni (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_e2f24aba4fef (Metraipolis archive dc_e2f24aba4fef, sha256 8ea7af5c677a2dc56985b301d1a1839c3e3afe76901ce2f773d6f3d2fff1c08f)

BibTeX

@misc{dce2f24aba4fef,
  title = {39 Cygni — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/39_Cygni},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_e2f24aba4fef; sha256 8ea7af5c677a2dc56985b301d1a1839c3e3afe76901ce2f773d6f3d2fff1c08f},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/39_Cygni. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

39 Cygni is a binary star system near the southern border of the northern constellation of Cygnus, approximately 270 light years away from Earth. It is visible to the naked eye as an orange-hued star with an apparent visual magnitude of 4.43. The system is moving closer to the Sun with a heliocentric radial velocity of −15 km/s. This is a single-lined spectroscopic binary with an orbital period of about 85.67 years (31,292 d) and an eccentricity of 0.5. The projected semi-major axis of the primary star's orbit is 1,207 ± 46 Gm (8.07 ± 0.31 AU), providing a lower bound on the separation of the stars. The system is around four billion years old. The visible component is an evolved K-type giant star with a stellar classification of K2.5 III Fe−0.5; the suffix notation indicates a mild underabundance of iron in the spectrum. It is probably on the horizontal branch, fusing helium in its core, but may be on the red giant branch fusing hydrogen in a shell around an insert helium core. It has 1.9 times the mass of the Sun and has expanded to 25 times the Sun's radius. The star is radiating 186 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,284 K. The unseen secondary component is most probably a main sequence star with a type between F and mid-K, although it may be a white dwarf instead. Its mass is at least 0.7–1.0 times the mass of the Sun. It was once designated h Cygni by John Flamsteed and was included in his Atlas Coelestis, but the designation is now dropped.

Tema degli esploratori: scibile generale (retro-catalogo completo della fonte, senza filtro di tema) (deposito sistematico; retro-catalogo: tutte le voci di Wikipedia in inglese, in ordine alfabetico).
Fonte: Wikipedia in inglese, voce «39 Cygni» — https://en.wikipedia.org/wiki/39_Cygni
Wikidata Q4636117: «stella nella costellazione del Cigno» (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q4636117
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/39_Cygni?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1370771568, consultata il 2026-11-06T14:40:32.015Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: f24f902604dcec914d91fa71c63b0ea8cc9db3933eea45095faa728a55783fd7