This artist’s impression shows one of the new planets orbiting the Sun-like star HD 85512 in the southern constellation of Vela, or the Sail. About 3.6 times as massive as the Earth, it lies at the edge of the habitable zone around its star and is one of a gamut of extrasolar planets found using the HARPS instrument on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile.
Credit: ESO/M. Kornmesser
SYDNEY: Sixteen super-Earths, one orbiting at the inner-edge of its star's habitable zone, are among the latest discovery of more than 50 exoplanets.
Presented at a conference earlier this week and set to appear in the journal Astronomy & Astrophysics, it's the largest haul of exoplanets ever revealed at one time.
They were found using the powerful spectrograph called HARPS, installed on a 3.6-metre telescope belonging to the European Southern Observatory in Chile, which monitors the intense radial-velocity of nearby Sun-like stars with incredibly high precision.
"The harvest of discoveries from HARPS has exceeded all expectations and includes an exceptionally rich population of super-Earths and Neptune-type planets hosted by stars very similar to our Sun," said astronomer Michel Mayor from the University of Geneva, and leader of the HARPS team.
"And even better," he added, "the new results show that the pace of discovery is accelerating."
Verging the habitable zone
Beginning in 2009, 10 nearby stars similar to the Sun were selected for a new survey. These stars had already been observed by HARPS and were known to be suitable for extremely precise radial velocity measurements.
The team of astronomers discovered five new planets with masses less than five times that of Earth.
One of the planets, HD 85512 b, is estimated to be only 3.6 times the mass of the Earth and is located at the inside edge of its parent star's habitable zone - the narrow region around a star in which conditions may enable the presence of liquid water, and possibly, support life.
This is the lowest-mass confirmed planet discovered by the radial velocity method that potentially lies in the habitable zone of a Sun-like star, and the second low-mass planet discovered by HARPS inside the habitable zone - the other being Gliese 581d, a rocky planet on the outer fringe of its habitable zone and the target of 25,880 'tweets' sent through Cosmos' Hello from Earth initiative.
"These planets will be among the best targets for future space telescopes to look for signs of life in the planet's atmosphere by looking for chemical signatures such as evidence of oxygen," said astronomer and lead author on one of the reports, Francesco Pepe, from the Geneva Observatory in Switzerland.
Low-mass planets likely
Working off observations of more than 376 Sun-like stars, the researchers have also improved estimates of how likely it is that such stars will host low-mass planets, saying 40% have at least one planet smaller than Saturn.
The discovery has researchers optimistic that habitable terrestrial planets can be found using the radial velocity technique - which measures the shift in wavelength of a star's spectrum to infer the presence of a planet.
"The detection of HD 85512 b is far from the limit of HARPS and demonstrates the possibility of discovering other super-Earths in the habitable zones around stars similar to the Sun," echoed Mayor. "In the coming 10 to 20 years we should have the first list of potentially habitable planets in the Sun's neighbourhood."
The discovery has brought the current number of exoplanets to more than 670, according to the online Extrasolar Planet Encyclopaedia catalogue.
Mankinds search for Extraterrestial life.
Mitar Tarabic., Serbian Seer., 1829-1899.
Man will travel to other worlds to find lifeless deserts there, and still, God forgive him, he will think that he knows better than God himself. There, except the eternal peace of God, he will see nothing, but he will sense with his heart and soul all of God's beauty and power. People will drive in rigs upon the moon and stars. They will look for life, but life similar to ours they will not find. It will be there, but they will not be able to understand it and see that it is life.
Arne Strand.Sweden.