Astronomers found a water snowline in a protoplanetary disk around a young star called V883 Orionis located 1,350 light years from Earth in the Orion Nebula Cluster. Normally, a water snowline cannot form near a star but a rapid increase in the brightness of V883 Orionis pushed the snowline farther out to an area with low temperatures and pressure conducive to the snowline’s formation.
As stated by the study published in the journal Nature, the young star is only 30 percent more massive than the sun but is already 400 times brighter and hotter. V883 Orionis’ recent outburst pushed the water snowline 40 astronomical units (AU) or 6 billion kilometers away from it, almost equivalent to Pluto’s distance orbit, allowing water to condense into a layer of ice on dust grains and other particles.
Normally, water molecules within 450 million kilometers or three AU around a star cannot freeze due to heat. The observations were made possible with the Atacama Large Millimeter/submillimeter Array (ALMA).
“The ALMA observations came as a surprise to us,” adds the study’s lead author Lucas Cieza, an astronomer at Diego Portales University in Santiago, Chile. “Our observations were designed to image disk fragmentation, which is one of the proposed mechanisms for the formation of giant planets. We saw none of that, as the disk is probably too warm to fragment despite its very large mass. Instead, we found what looks like a ring at 40 AU. This illustrates well the transformational power of ALMA, which delivers exciting results even if they are not the ones we were looking for.”
The findings also support the theory that water ice plays an important role in planet formation. According to the study’s co-author Zhaohuan Zhu, an astronomer at Princeton University in New Jersey, water ice regulates the accumulation of dust grains into larger particles, consequently forming smaller, rocky planets, like our planet and Mars. The ice outside the water snowline also helps create snowballs and cometary bodies that give way to giant gaseous planets like Jupiter.