14 DAY TRIAL // The High Accuracy Radial velocity Planet Searcher (HARPS) instrument is one of the most skilled in the world at finding exoplanets. This was evidenced by the fact that it recently helped identify no less than 32 new exoplanets, from the super-Earth (or Neptune-like) class. Thus far, the high-precision echelle spectrograph has found about 75 exoplanets in 30 different planetary systems, out of a total of more than 400 known exoplanets. HARPS was installed on the European Southern Observatory's (ESO) 3.6-meter telescope, at the La Silla Observatory in Chile, in 2002.
“HARPS is a unique, extremely high precision instrument that is ideal for discovering alien worlds. We have now completed our initial five-year program, which has succeeded well beyond our expectations,” expert Stephane Udry, the spokesperson who has made the announcement, says, quoted by AlphaGalileo. The spectrograph saw the first light in February 2003, and has been scanning the skies in search of Earth-like exoplanets ever since. In order to ensure its precision, HARPS is kept in a vacuum chamber, in which the temperature is controlled within a range of 0.01 degrees Celsius.
“These observations have given astronomers a great insight into the diversity of planetary systems and help us understand how they can form,” ESO team member Nuno Santos explains. “By targeting M dwarfs and harnessing the precision of HARPS we have been able to search for exoplanets in the mass and temperature regime of super-Earths, some even close to or inside the habitable zone around the star,” Xavier Bonfils, the co-author of the new investigation, adds. One of the main reasons why HARPS has been so successful is the fact that the consortium operating the instruments has been very “picky” in selecting the targets to be observed with the spectrograph.
The instrument is one of the only two machines in the world that can attain a precision of one meter/second. This means that, even after its official survey period is over, it will continue to remain a reference in the field. Most likely, its team members say, it will be used to scout M dwarfs and look for planets as close to the mass of our own Earth. It will also prefer exoplanets that may orbit their parent stars inside habitable zones, which is the area where conditions are appropriate for the existence of liquid water.
Hundreds of stars have had their radial velocities measured over the past few years. This is one of the main focuses of HARPS, and it is especially suited to identify small exoplanets because of its massive resolution. In the case of a large planet, its parent star can change its radial velocity by as little as 3.5 kilometers/hour.