Orion variable

Orion variable

An Orion variable is a variable star which exhibits irregular and eruptive variations in its luminosity and is typically associated with diffuse nebulae. It is thought that these are young stars which will later become regular, non-variable stars on the zero-age main sequence. Brightness fluctuations can be as much as several magnitudes.

T Tauri stars are Orion variables exhibiting characteristic fluorescent violet emission lines from singly ionized Iron (FeII) in their star spectra, and also emission from Lithium, a metal that usually is destroyed by the nuclear fusion in the stars.

FU Orionis stars or simply "Fuors", are Orion variables that rise 5-6 magnitudes sink up to one magnitude and stay there for many decades. The prototype is FU Orionis, and other specimens are V1057 Cygni and V1515 Cygni.

Of this diverse class of stars, some Orion variables may exhibit a small amplitude (up to 1 magnitude) periodic variation, some are characterized by abrupt fadings, and some show spectral characteristics indicating mass downfall upon the star (YY Orionis stars). Many of these characteristics may occur in any one Orion variable.

References

Samus N.N., Durlevich O.V., et al. Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.)

External links


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Orión (constelación) — Para otros usos del término, véase Orión (desambiguación). Orion Nombre Latino Orion Abr …   Wikipedia Español

  • Orion (constellation) — For other uses, see Orion (disambiguation). Orion Constellation List of stars in Orion Abbreviation Ori Genitive Orionis …   Wikipedia

  • Variable star — A star is classified as variable if its apparent brightness as seen from Earth changes over time, whether the changes are due to variations in the star s actual luminosity, or to variations in the amount of the star s light that is blocked from… …   Wikipedia

  • Orion (constellation) — Pour les articles homonymes, voir Orion. Orion Vue de la constellation Désignation …   Wikipédia en Français

  • Orion — /euh ruy euhn/, n., gen. Orionis /awr ee oh nis, or , euh ruy euh nis/ for 2. 1. Class. Myth. a giant hunter who pursued the Pleiades, was eventually slain by Artemis, and was then placed in the sky as a constellation. 2. Astron. the Hunter, a… …   Universalium

  • Constellation d'Orion — Orion (constellation) Pour les articles homonymes, voir Orion. Orion …   Wikipédia en Français

  • Constellation d’Orion — Orion (constellation) Pour les articles homonymes, voir Orion. Orion …   Wikipédia en Français

  • Estrella variable — La estrella supergigante roja, Betelgeuse, vista desde una distancia de 8 unidades astronómicas Las estrellas variables son estrellas que experimentan una variación en su brillo en el transcurso del tiempo. Algunas son muy conocidas y son el… …   Wikipedia Español

  • Master of Orion II: Battle at Antares — Master of Orion II Battle at Antares Éditeur MicroProse, Infogrames (PC) Macsoft (Mac) Développeur Simtex Date de sortie 31 octobre 1996 (États Unis) décembre 1996 (France) Version …   Wikipédia en Français

  • Master of Orion II — Master of Orion II: Battle at Antares Master of Orion II Battle at Antares Éditeur MicroProse, Infogrames (PC) Macsoft (Mac) Développeur Simtex Date de sortie 31 octobre 1996 (États Unis) décembre 1996 (France) V …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”