ALMA spots huge planets forming around young stars
A team of astronomers has made use ofthe Atacama Large Millimeter/submillimeter Array (ALMA) to observe four distant stars, finding the best evidence yet of massive planetsforming in the surrounding disk of dust and gas. The observations,which wouldn't have been possible without the instrument, have helpedscientists to confirm an existing theory on planet formation.
While planets are born around almostevery star, we still don't fully understand the processes by whichthey form. The European Southern Observatory's (ESO) ALMA telescopeoffers unparalleled sensitivity and image sharpness, allowingastronomers to peer at the disks of material that swirl arounddistant young stars, picking out clues about planet birth thatsignificant advance our understanding.
One particular mystery surrounds aparticular class of disk, known as transitional disk. There's anotable lack of dust in the central region of these structures, whichscientists theorize could be due to the effect of stellar winds andhigh levels of radiation, or the fingerprints of massive youngplanets moving through the material.
The ESO team used ALMA to map thedistribution of dust and gas within four transitional disks, findingsthat while there is a significant drop in dust levels in the observedgaps, plenty of gas is present. That said, a gap in the gasdistribution does also exist – some three times smaller than thedust gap.
While previous observations have leftastronomers with no clear indication of which of the two theories iscorrect, the new data clearly points to the presence of huge planetswith masses several times that of Jupiter, sweeping through thematerial, creating vast channels in the disks.
Impressively, the observations weremade before ALMA was fully operational, and make use of just onetenth of the installation's power. Further observations will now bemade to confirm that the finding in a larger sample of transitionaldisks. Looking even further forward, future instruments will surpasseven ALMA's impressive abilities, boasting the capabilities to delveeven deeper into the make-up of such distant objects.
"Direct planetarydetection is just within reach of current instruments, and the nextgeneration telescope currently under construction, such as theEuropean Extremely Large Telescope, will be able to go much further," says team lead Nienke van der Marel of the Leiden Observatory in the Netherlands. "ALMA is pointing out where they will need to look."
The findings of the research werepublished in the journal Astronomy & Astrophysics.
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