Astronomers discover dust-rings and possible indication of ringed planet existence
Exciting discovery: Our neighboring star Proxima Centauri could have more than just one planet. This is indicated by data from the ALMA Observatory in Chile. Thus, beyond the planet Proxima Centauri b, there are probably not just three rings of dust and asteroids. A compact source of heat could also indicate the existence of a ringed planet the size of Saturn.
Our neighboring star Proxima Centauri has multiple dust rings - and maybe even a second planet. © ESO/ M. Kornmesser
The Red Dwarf Proxima Centauri is only about four light-years away from us - it is our next stellar neighbor. All the more exciting was the discovery of a potential twin earth around this nearby star in 2016. Because of the relatively short distance to this system, this Earth-like and possibly even life-friendly planet could be the first exoplanet Earth's space explorers visit in the distant future.
Heat radiation of several dust rings
But as it turns out, Proxima Centauri has more to offer than just one planet. When astronomers observed the red dwarf with the ALMA observatory in Chile, they registered an excess of heat radiation that can not come from the star itself. Instead, the features of this thermal emission suggest that they emanate from extensive dust rings in the orbit of the dwarf star.
The exciting thing is that :
the structure and dynamics of such dust belts can provide important information about the formation and development of exoplanet systems, explain Guillem Anglada of the Astrophysical Institute of Andalusia in Granada and his colleagues.
Because these belts typically collect dust and asteroids left over from planetary formation. Even collisions of planets can produce such rings.
Three rings ...
This rough draft, not to scale, shows the location of the dust rings and the possible second planet around Proxima Centauri. © after Anglada et al.
According to the ALMA data, there is a dust ring several million kilometers wide at about one to four astronomical units from Proxima Centauri. The astronomers estimate the temperature of the dust in this ring to be minus 230 degrees, which is about the same as in the Kuiper belt of our solar system. The dust in this ring could have a total mass of about one hundredth of the Earth's mass.
A second, even colder dust ring could surround the dwarf star in about 30 astronomical units distance.
This ring could cover a third of the Earth's mass - that is much more than the Kuiper Belt, reports Guillem Anglada of the Astrophysical Institute of Andalusia in Granada. There is no equivalent in the solar system.
A third, much warmer dust ring could exist just outside the orbit of Proxima Centauri b.
... and another planet?
Even more exciting, however, is another source of thermal radiation in the Proxima system: Around 1.6 astronomical units away from the star, the researchers detected another surplus of heat radiation.
This source is very exciting, they emphasize.
Because it is a rather compact object, not over the entire star orbit distributed belt.
According to the astronomers, it can not be ruled out that this could be the signature of a second, as yet undiscovered planet around Proxima Centauri.
If this scenario is correct, then it could be a planet of the mass of Saturn, report Anglada and his colleagues. The source of thermal radiation would then be a dust ring surrounding this gas giant.
This result would be the first indication after the discovery of the Earth-like planet Proxima b, that there is not just a single planet around the solar star, but a whole planetary system, notes Anglada.
Whether these planets exist and where they are hiding must now be explored further.
Source: Cornell University Library arXiv