Des étoiles qui ressemblent à des comètes
Cette spectaculaire image de la semaine a été produite à partir des données recueillies par le télescope ALMA (Atacama Large Millimeter/submillimeter Array) dans le désert d’Atacama au Chili, associées aux données du télescope spatial Hubble de NASA/ESA . Elle montre un groupe d'étoiles appelé Westerlund 1, l'un des groupes d'étoiles les plus massifs et les plus jeunes de la Voie Lactée.
Un détail passionnant: cette image montre également les «queues» de matériaux ressemblant à des comètes s’éloignant de certaines des étoiles géantes de Westerlund 1. Ces queues se forment dans les vents épais et impitoyables qui proviennent des résidents stellaires de l’amas et qui transportent de la matière vers l’extérieur. Ce phénomène est similaire à la façon dont les comètes obtiennent leurs célèbres queues. Les queues de comètes du système solaire sont crées à partir du noyau de leur comète mère par un vent de particules émanant du Soleil. Par conséquent, les queues de comètes sont toujours dans la direction opposée à notre Soleil. De même, les queues des énormes étoiles rouges montrées dans cette image s’éloignent du noyau de l’amas, probablement à cause des vents puissants de l’amas générés par les centaines d’étoiles chaudes et massives situées dans le centre de Westerlund 1.
Ces structures massives couvrent de grandes distances et indiquent l'effet dramatique que l'environnement peut avoir sur la formation et l'évolution des étoiles. Ces queues ressemblant à des comètes ont été détectées lors d’une étude ALMA de Westerlund 1 qui visait à explorer les étoiles constitutives du groupe et à déterminer comment et à quelle vitesse elles perdent leur masse. Le groupe est connu pour héberger une grande quantité d'étoiles massives, dont beaucoup d'un type rare et intrigant, ce qui le rend très intéressant et utile pour les astronomes souhaitant comprendre la myriade d'étoiles de notre galaxie.
Crédit:ESO/D. Fenech et al.; ALMA (ESO/NAOJ/NRAO)
Acknowledgments: Mahdi Zamani
À propos de l'image
| Identification: | potw1849a |
| Langage: | fr-ch |
| Type: | Observation |
| Date de publication: | 3 décembre 2018 06:00 |
| Taille: | 1838 x 1929 px |
À propos de l'objet
| Nom: | Westerlund 1 |
| Type: | Milky Way : Star : Grouping : Cluster : Open |
| Constellation: | Ara |
Fonds d'écran
Coordinates
| Position (RA): | 16 47 3.98 |
| Position (Dec): | -45° 50' 52.97" |
| Field of view: | 2.76 x 2.90 arcminutes |
| Orientation: | North is 44.2° right of vertical |
Couleurs & filtres
| Domaine | Longueur d'onde | Télescope |
|---|---|---|
| Visible R | 625 nm | Very Large Telescope OmegaCAM |
| Visible G | 480 nm | VLT Survey Telescope OmegaCAM |
| Visible H-alpha | 659 nm | Very Large Telescope OmegaCAM |
| Visible H-alpha | 659 nm | Very Large Telescope OmegaCAM |
| Visible I | 770 nm | Very Large Telescope OmegaCAM |
| Infrarouge J | 1.25 μm | Hubble Space Telescope WFC3 |
| Infrarouge J | 1.25 μm | Hubble Space Telescope WFC3 |
| Infrarouge H | 1.6 μm | Hubble Space Telescope WFC3 |
| Infrarouge Water-CH4 | 1.39 μm | Hubble Space Telescope WFC3 |
| Infrarouge Water-CH4 | 1.39 μm | Hubble Space Telescope WFC3 |
| Millimétrique 100 GHz | 3.0 mm | Atacama Large Millimeter/submillimeter Array Band 3 |
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