Glossary term: Estrella binaria
Description: Una estrella binaria es un sistema formado por dos estrellas que orbitan alrededor de su centro de masa común debido a que están unidas por la fuerza de la gravedad. Sus órbitas siguen las leyes de Kepler y tienen forma elíptica (parecida a un círculo aplanado) o circular.
Más de la mitad de todas las estrellas de la Vía Láctea se encuentran en sistemas binarios o forman parte de sistemas con más de una estrella compañera (conocidos como sistemas estelares múltiples de orden superior). Debido a sus enormes distancias de la Tierra, la mayoría de las estrellas binarias y los sistemas estelares múltiples de orden superior se ven para el observador como una sola estrella.
Las estrellas binarias pueden clasificarse en varias categorías según el método de observación mediante el cual se descubrió que eran estrellas binarias. Pueden pertenecer simultáneamente a más de una categoría:
Las binarias visuales pueden observarse como dos estrellas separadas muy próximas entre sí en el cielo. No todas las estrellas que parecen estar cerca en el cielo (estrellas dobles) son binarias unidas por la gravedad; algunas pueden estar cerca en el cielo por casualidad, pero no estar unidas por la gravedad. Las estrellas dobles que no son binarias unidas por la gravedad pueden estar separadas por cientos de años luz de distancia.
Las binarias espectroscópicas se detectan gracias al desplazamiento Doppler de las líneas del espectro de las estrellas, ya que estas orbitan alrededor de su centro de masa común.
Las binarias eclipsantes pueden detectarse cuando una de las estrellas del sistema pasa entre su compañera y el observador, bloqueando parte de la luz de la estrella compañera y haciendo que la luz combinada del sistema parezca brevemente más tenue.
Las binarias astrométricas son sistemas en los que solo se observa una imagen estelar —ya sea porque una de las estrellas es demasiado tenue para ser observada o porque las imágenes de las dos estrellas se superponen—, pero en los que el movimiento orbital de las estrellas del sistema binario hace que el punto más brillante de la imagen estelar muestre un cambio periódico de posición en el cielo.
Related Terms:
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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher The translation of this term and its definition is still awaiting approval
The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".
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In Other Languages
- Árabe: النجم المزدوج
- Alemán: Doppelsternsystem
- Inglés: Binary Star
- Francés: Étoile binaire
- Italiano: Stella binaria
- Japonés: 連星 (external link)
- Maratí: तारा युगल
- Chino simplificado: 双星
- Chino tradicional: 雙星
Related Media
A binary brown dwarf system revealed
Caption: This image presents a nearby system of brown dwarfs, objects that fall between planets and stars in mass and do not sustain long-term nuclear fusion in their cores. Located about 6.5 light-years from Earth, this system (known as Luhman 16) is the third closest system to the Solar System after the Alpha Centauri system and Barnard's Star. It was initially observed as what seemed to be a single faint source of infrared light. Brown dwarfs are often difficult to study because of their low brightness, especially in visible light. However they shine brighter in infrared light due to their cooler effective temperatures.
The comparison highlights the importance of observational resolution. The image at the center, taken by NASA’s Wide-field Infrared Survey Explorer (WISE), shows the system as a single blurred object due to its lower resolution (WISE has a resolution of roughly 6 arcseconds). A highlighted zoomed-in view from the Gemini South Observatory in Chile reveals that this “single” source is actually a binary system of two brown dwarfs. The improved angular resolution (roughly 0.6 arcseconds) allows astronomers to separate the two objects clearly, demonstrating how higher-resolution observations uncover hidden structures in the universe. While the Gemini telescope is situated on the Earth and thus is affected by the blurring effects of the Earth's atmosphere, it has a substantially larger mirror than the WISE telescope (8m wide vs. 40cm wide) meaning it can achieve much higher resolutions.
Credit: NASA/JPL/Gemini Observatory/AURA/NSF
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License: PD Public Domain icons
Related Diagrams
Carina Constellation Map
Caption: The constellation Carina along with its bright stars and surrounding constellations. Carina is surrounded by (going clockwise from the top): Vela, Puppis, Pictor, Volans, Chamaeleon, Musca and Centaurus. Carina is notable for Canopus, the second brightest star in the night sky and for the famous variable star Eta Carinae. This latter object is a binary star system of two young very massive stars. Its brightness has varied greatly over the past few centuries. At one point it outshone Canopus before dimming by a factor of four thousand to become invisible to the naked eye. In recent years it has brightened enough to again be visible without the aid of a telescope.
Carina is a southern constellation and thus the whole constellation is visible at some point in the year to the entire southern hemisphere. The whole constellation is also visible from equatorial regions of the northern hemisphere with parts of the constellation visible from northern temperate regions.
The open clusters NGC 2516, NGC 3532 and IC 2602 lie in Carina. These are marked here by yellow circles. The Carina Nebula, also known as NGC 3372, lies in the constellation. This large nebula contains many massive young stars, including Eta Carinae.
This diagram maps an area around the south celestial pole. Here lines of constant right ascension converge. The right ascension values of these lines are marked on the x-axis above and below the diagram. Some of the lines of constant declination are marked on the y-axis. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. Carina was previously part of the larger Argo Navis constellation along with Vela and Puppis. As the letter designations for stars were created before this division took place, Greek letter designations are now divided between the three constellations with Carina having stars designated alpha and beta but no gamma or delta. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope
License: CC-BY-4.0 Creative Commons Reconocimiento 4.0 Internacional (CC BY 4.0) icons
