UK astronomers contribute to the discovery of a new potential planetary system

3 November 2017

Proxima Centauri

Artist’s impression of the dust belts around Proxima Centauri.
(Credit: ESO)

Dust detected around the closest star to the solar system, Proxima Centauri, may indicate the presence of an elaborate planetary system.

An international team, that included astronomers from Queen Mary University London and the University of Manchester, used the ALMA Observatory in Chile to make these new observations.

Their findings revealed the glow coming from cold dust in a region that is between one to four times as far from Proxima Centauri as the Earth is from the Sun.

The data also hint at the presence of an even cooler outer dust belt and may indicate the presence of an elaborate planetary system. These structures are similar to the much larger belts in the Solar System and are also expected to be made from particles of rock and ice that failed to form planets.

Proxima Centauri is the closest star to the Sun. It is a faint red dwarf lying just four light-years away in the southern constellation of Centaurus (The Centaur). It is orbited by the Earth-sized temperate world Proxima b, discovered in 2016 and the closest planet to the Solar System. But there is more to this system than just a single planet. The new ALMA observations reveal emission from clouds of cold cosmic dust surrounding the star.

Co-author of the study Dr Guillem-Anglada-Escudé, from QMUL, said: “The cold dust detected by ALMA is really important because it shows the new level of detail that we can reach in understanding planetary systems when focusing on these very nearby stars with new generation observatories.

These observations show that Proxima Centauri seems to hold a rich planetary system with an interesting dynamical history rather than just Proxima b, which we discovered last year.”

Dust belts are the remains of material that did not form into larger bodies such as planets. The particles of rock and ice in these belts vary in size from the tiniest dust grain, smaller than a millimetre across, up to asteroid-like bodies many kilometres in diameter

Proxima Centauri's planetary system is also particularly interesting because there are plans — the Starshot project - for future direct exploration of the system with microprobes attached to laser-driven sails. Knowledge of the dust environment around the star will be essential for planning such a mission.

Further information

You can learn more about the findings here.

STFC, the UK and ALMA

UK involvement in the construction of ALMA included STFC’s Rutherford Appleton Laboratory and UK Astronomy Technology Centre, the Cavendish Laboratory at the University of Cambridge, the University of Manchester and the University of Kent, all of whom played key roles in the design and construction of ALMA.

STFC, as the UK partner with the European Southern Observatory (ESO) helps support UK astronomers working on the data coming from ALMA.

The Atacama Large Millimetre/submillimetre Array (ALMA), located in the Atacama Desert of Northern Chile at an altitude of over 5000m combines a giant array of fifty 12-m antennas, which can be configured to achieve baselines up to 16 km. It is equipped with state-of-the-art receivers that cover all the atmospheric windows up to 1 THz. In addition, a compact array of 7-m and 12-m antennas greatly enhance ALMA's ability to image extended sources.  ALMA is used to detect and study the earliest and most distant galaxies, and probe dust-obscured regions which are the birthplace of stars and planets.

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