Le système binaire R Aquarii observé en 2012 par le VLT
Cette image révèle un système d'étoiles binaires dramatique nommé R Aquarii, situé à 700 années-lumière de la Terre, comme l'a observé en 2012 le Very Large Telescope (VLT) de l'ESO.
R Aquarii est une étoile binaire symbiotique, composée de deux étoiles entourées d'un vaste nuage de gaz dynamique (une nébuleuse). De tels systèmes contiennent deux étoiles dans une relation inégale et complexe. R Aquarii est composé d’une naine blanche et d’une géante rouge. La géante rouge perd de la matière vers la naine blanche et éjecte parfois de la matière en jets, boucles et traînées étranges, formant ainsi les formes curieuses que l'on voit sur ces images.
Il se passe beaucoup de choses entre ces deux acteurs de ce ballet cosmique. La géante rouge est une étoile variable et varie en luminosité d’un facteur 750 tous les ans et trois semaines. La faible nébuleuse est nommée Cederblad 211 et résulterait d’une violente nova il y a 250 ans. On peut également voir une forme en S étroite et verticale, avec de la matière surchauffée se déplaçant vers l’extérieur à des vitesses extraordinaires allant de 600 à 850 km/s.
R Aquarii a également été observée il y a 15 ans - et plusieurs fois dans l'intervalle - pour suivre son évolution. Le système est très dynamique et complexe, s’est étendu et a considérablement évolué au cours des dernières années (une image de 1997 est visible ici, et une comparaison entre les deux est disponible ici).
Crédit:ESO
À propos de l'image
| Identification: | potw1850a |
| Langage: | fr-ch |
| Type: | Observation |
| Date de publication: | 10 décembre 2018 06:00 |
| Taille: | 1873 x 1166 px |
À propos de l'objet
| Nom: | R Aquarii |
| Type: | Milky Way : Star : Grouping : Binary |
| Distance: | 1000 années lumière |
| Constellation: | Aquarius |
Fonds d'écran
Coordinates
| Position (RA): | 23 43 49.60 |
| Position (Dec): | -15° 17' 11.67" |
| Field of view: | 5.99 x 3.73 arcminutes |
| Orientation: | North is 0.1° left of vertical |
Couleurs & filtres
| Domaine | Longueur d'onde | Télescope |
|---|---|---|
| Visible O III | 500 nm | Very Large Telescope FORS2 |
| Visible O II | 372 nm | Very Large Telescope FORS2 |
| Visible H-alpha | 656 nm | Very Large Telescope FORS2 |
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