Nuovi osservazioni nei dischi di detriti
Impiegando 39 delle 66 antenne dell’Atacama Large Millimeter/submillimeter Array (ALMA), situato a 5000 metri di altitudine sull’altipiano di Chajnantor nelle Ande cilene, gli astronomi sono stati capaci di rilevare monossido di carbonio (CO) nel disco di detriti attorno a una stella di tipo F. Malgrado il monossido di carbonio sia la secondo molecola più comune nel mezzo interstellare dopo l’idrogeno molecolare, è la prima volta che il CO è stato rilevato attorno ad una stella di questo tipo. Questa stella, chiamata HD 181327, è un membro dell’associazione Beta Pictoris, situata a 170 anni-luce dalla Terra.
Fino ad adesso, la presenza di CO è stata rilevata solo attorno a poche stelle di tipo A, sostanzialmente più massicce e luminose di HD 181327. Impiegando la stupenda risoluzione spaziale e la sensibilità offerta dall’osservatorio ALMA, gli astronomi sono ora capaci di riprendere questo stupendo anello di fumo e di mappare la densità del CO all’interno del disco.
Lo studio di dischi di detriti è una delle possibilità di descrivere i sistemi planetari e il risultato della formazione di pianeti. Si è scoperto che il gas CO si trova alla stessa posizione dei grani di polvere nel disco di detriti e che è stato prodotto recentemente. Collisioni distruttive di planetesimi di ghiaccio nel disco sono possibili sorgenti per il rifornimento continuo di CO. Collisioni in dischi di detriti richiedono tipicamente che i corpi di ghiaccio siano perturbati gravitazionalmente da corpi più grossi per poter raggiungere velocità di collisione sufficienti. Inoltre la composizione del CO dei planetesimi di ghiaccio nel disco è consistente con le comete nel nostro sistema solare. Questa seconda possibilità per spiegare l’origine del gas CO suggerisce che le comete di ghiaccio siano comuni attorno a stelle simili al nostro Sole, il che ha forti implicazioni per la sostenibilità della vita negli exopianeti terrestri.
I risultati sono stati pubblicati nel giornale Monthly Notices of the Royal Astronomical Society con il titolo “Exocometary gas in the HD 181327 debris ring” da S. Marino et al.
Link
pubblicazione scientifica da Marino et al.
Crediti:
ESO/Marino et al.
A proposito dell'immagine
| Identificazione: | potw1621a |
| Lingua: | it |
| Tipo: | Osservazione |
| Data di pubblicazione: | Lunedì 23 Maggio 2016 06:00 |
| Dimensione: | 2000 x 2000 px |
A proposito delll'oggetto
| Nome: | HD 181327 |
| Tipo: | Milky Way : Star : Circumstellar Material : Disk : Debris |
| Distanza: | 170 Anni luce |
| Constellation: | Telescopium |
Formati delle immagini
Coordinate
| Position (RA): | 19 22 58.99 |
| Position (Dec): | -54° 32' 18.21" |
| Field of view: | 0.13 x 0.13 arcminutes |
| Orientazione: | Il Nord è a -0.0° a sinistra della verticale |
Colori e filtri
| Banda | Telescopio |
|---|---|
| Millimetrico 220 GHz | Atacama Large Millimeter/submillimeter Array |
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