Astronomers in Chile have unearthed a number of new exoplanets orbiting a star that perfectly mimics our own Sun — fueling hopes that Earth-like conditions may exist elsewhere in the Universe.
The discovery was made by studying a distant star cluster using the European Southern Observatory’s (ESO) HARPS planet finder telescope by a team of Chilean astronomers based in La Silla.
Coined Messier 67, the cluster is the first ever recorded to host planet-orbiting stars. This finding is particularly significant because only a small number of planets have been sighted in star clusters previously.
Planets orbiting stars outside our own Solar System are no rarity — many have been observed using powerful telescopes in the past. However, one of the newly discovered exoplanets is orbiting a star that is a rare solar twin — meaning that the star is practically identical to the Sun in every way. Moreover, these three particular exoplanets are inside a star cluster, which is strange.
“This is an important discovery because previous searches in clusters found it difficult to detect planets,” James Jenkins, an astronomer at the Universidad de Chile, told This is Chile. “However, these results suggest that planets in clusters are as numerous as planets around regular field stars like the Sun.”
Jenkins also explained that stars in clusters are thought to have the same age and chemical make-up and are therefore excellent laboratories to study how planet formation depends on stellar mass and chemical composition. Adding further importance to their discovery.
“One of the stars they have found to have a planet is one of the best solar-twins that astronomers have currently discovered. This is important to test how rare the solar system really is,” said Jenkins.
Star clusters typically come in two types. Open clusters are groups of stars that have formed together from a single cloud of gas and dust in the recent past — they are mostly found in the spiral arms of galaxy such as the Milky Way. Globular clusters are much larger, spherical collections of older stars that orbit around the center of a galaxy. Despite research, no planets have so far been found in globular clusters.
“These new results show that planets in open star clusters are about as common as they are around isolated stars — but they are not easy to detect,” said Luca Pasquini, astronomer and co-author of the new paper detailing the new discovery.
“The new results are in contrast to earlier work that failed to find cluster planets, but agrees with some other more recent observations. We are continuing to observe this cluster to find how stars with and without planets differ in mass and chemical makeup,” he added.
The HARPS planet finder telescope is specially designed to obtain very high long-term radial velocity — a very advanced and expensive tool. ESO is the foremost intergovernmental astronomy organization in Europe and is the world’s most productive astronomical observatory.
Chile already boasts just under half of the world’s astronomy infrastructure of telescopes and this number is expected to increase to 70 percent by 2020. David Azocar, communications officer of the Center for Excellence in Astrophysics and Associated Technologies (CATA), told The Santiago Times why the country has the world’s most lauded skies when it comes to astronomical development.
“In the North of Chile, which is where astronomical observatories are concentrated, there is a happy mixture of many clear nights and low humidity,” he said. “Both are factors which favor the work of scientific instruments. In addition, Chile has very good astronomers — many of them trained in the most prestigious universities in the world.”