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Sixteen super-Earths among fifty new exoplanets discovered by HARPS


September 12, 2011

Artist's impression of the rocky super-Earth HD 85512 b - one of more than 50 new exoplanets found by HARPS (Image: ESO/M. Kornmesser)

Artist's impression of the rocky super-Earth HD 85512 b - one of more than 50 new exoplanets found by HARPS (Image: ESO/M. Kornmesser)

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The European Southern Observatory (ESO) has announced its exoplanet-hunting HARPS (High Accuracy Radial velocity Planet Searcher) has discovered 50 new exoplanets, making it the largest amount of exoplanets that has been announced at the one time. Bringing the number of planets discovered outside our solar system to 645, the 50-planet haul includes 16 super-Earths (planets with a mass between one and ten times that of Earth), including one that orbits at the edge of the habitable zone of its star.

Whereas NASA's Kepler spacecraft looks for fluctuations in the brightness of stars to detect planets passing in front of it, HARPS is a high precision echelle spectrograph that observes Doppler shifts in the spectrum of the star around which a planet orbits. In contrast to the majority of planets discovered by the transit method employed by Kepler, which are very distant from us, the planets found by HARPS are around stars that are much closer, making them better targets for many kinds of additional follow-up observations.

HARPS discovered its first super-Earth in the habitable zone, (Gliese 581 d), in 2007. More recently, it was also used to demonstrate that the other candidate super-Earth in the habitable zone around star Gliese 581 (Gliese 581 g) doesn't exist.

In the eight years since HARPS achieved first light, its observations have allowed astronomers to improve the estimate of how likely it is that a star like the Sun is host to low-mass planets as opposed to gaseous giants. By studying the properties of all the HARPS planets discovered so far, the team has found that about 40 percent of stars similar to the Sun have at least one planet lighter than Saturn. Additionally, the majority of exoplanets of Neptune mass or less appear to be in systems with multiple planets.

With upgrades to both hardware and software, the team is increasing the sensitivity of HARPS, to search for rocky planets that could support life. One potential candidate is the newly discovered HD 85512 b, which is estimated to be just 3.6 times the mass of the Earth and is located at the edge of the habitable zone where water may be present in liquid form if conditions are right.

"This is the lowest-mass confirmed planet discovered by the radial velocity method that potentially lies in the habitable zone of its star, and the second low-mass planet discovered by HARPS inside the habitable zone," says Lisa Kaltenegger of the Max Planck Institute for Astronomy and Harvard Smithsonian Center for Astrophysics.

The team says that HARPS is now so sensitive that it can detect radial velocity amplitudes of significantly less than 4 km/h (2.5 mph), allowing it to detect planets under two Earth masses. Earth induces a 0.32 km/h (0.2 mph) radial velocity on the Sun.

HARPS is currently installed on ESO's 3.6 m Telescope at La Silla Observatory in Chile but a copy of HARPS is to be installed on the Telescopio Nazionale Galileo in the Canary Islands, to survey stars in the northern sky. Additionally, a new and more powerful planet-finder, called ESPRESSO, (Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations), will be installed on ESO's Very Large Telescope in Chile in 2016. It will boast radial velocity precision of 0.35 km/h (0.22 mph) or less, giving it the ability to discover Earth-mass planets in the habitable zone of low-mass stars.

"In the coming ten to twenty years we should have the first list of potentially habitable planets in the Sun's neighborhood. Making such a list is essential before future experiments can search for possible spectroscopic signatures of life in the exoplanet atmospheres," concludes Michel Mayor, who leads the ESO's HARPS team.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

What\'s the point of finding new earth-like planets while we are still pretty much premitive on our own? Another problem, how we get there? Are we going to send our kinds to colonize it by exterminate the natives?


The importance of looking for extraterrestial life is obvious: Are we alone? We are not going to meet in \"Person\" in any foreseeable future. But think about, what the mere existence of (other) sentient beings will impose on the way, we think.

Henrik Fleischer
The point? The point, my friend, is to find other intelligent life in our own Galaxy. To find habitable planets, orbiting suitable stars, where we may, soon, be able to send humanity so we don\'t have all our eggs in one fragile, and at present, deteriorating basket! You have been reading the news? Watching television? paying attention to what is going on in the world around you? Pollution, energy crisis, over-fishing, habitat destruction, crude oil depletion and on and on. These are very good reasons to want to try to save humanity from the one \"basket\" where we\'re presently living. As a race we\'re using expediency as an excuse to use our kitchens as our bathrooms and garbage dumps. In other words, we\'re shitting where we eat. We can not survive this and our Governments, being owned and controlled by Corporations, are incapable of caring for the populous they were sworn and hired to protect. All enemies, foreign and domestic! That\'s, word for word, from the oath they took when they took office. Greed has destroyed the one barrier you had that was protecting you from the corporations who\'s only concern is the bottom line. What you\'re living with now is rapacious greed unchecked. If you believe you, by way of your descendents, will survive in the (very near) future, then your head\'s farther up your sphincter than it should physically be able to go. Your vote is useless. Your choices predetermined by the self-same interests who will control those choices once in office. and even if you could locate an honest, incorruptible politician who\'ll dedicate themselves to saving the world, there\'s always assassination to get rid of the income bottleneck... Think about it next time you hear people yelling for revolution... here, in America. semajretrac

All these so called \"habitable\" planets are just habitable for humans but if they are aliens it is highly unlikely that they live under the same conditions that we do such as in the 20 to 30 degree temperature range with liquid water at room temperature. It is more likely that people are investigating these planets for a potential new planet for us to move to and ultimately destroy and then move on. I am sure that some people see that it is more pratical to move to another planet than try to save this one.

Yusuf Khan

As hindu scriptures say ... \'Their are 400 human types similar to us in the solar system, the question is getting the technology to physically getting their to say Hi!\'.

Harpal Sahota

"Only the unimaginative can believe that mankind's future is tied to one small overstrained planet in a galaxy of plenty. The meek shall inherit the Earth, The rest will inherit a Universe!"

"For the human race to survive, then but for a short time in our history the term "ship" must refer to a spaceship."

History Nut

Imagine dis........v founs a planet \"habitable\" in our neighbourhood.......due to high population intensity hr sm of us r transported tr.....for dis again a new technology is invented......to travel i@ a C volociety....(dat of speed of light) & again technology to communicate to each other....( from Earth to Earth2!) Evetything fine uptill now....Now imagine as said E2 revolves around its Sun in 60 days....so d person will tend to be called 6 yrs old in 1 yr of E1... ha ha ha.... More funny....As d mass of d E2 is different....it will change d g ( gravitational accelaration) Which v call as G ( counting it as comstant......) Trust me! All ur reflex action dat u hv accured tr ages....( which include ur ansistors) r gone with d wind!

Wat say?

Orzy Raj

History nut; Parse the King James translation; at the time, "meek" meant calm, slow to anger. Puts a different spin on it, huh?

semaxxxxx; Utter drivel. The planet is fine, and we're part of it. There's also technology in the near-term pipeline that will make things even better, to a massive degree.

Brian Hall
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