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32 planets discovered outside solar system

Posted on 20. Nov, 2009 by naresh in Blog, Space

Thirty-two planets have been discovered outside Earth’s solar system through the use of a high-precision instrument installed at a Chilean telescope, an international team announced.

This artist's rendering shows one of the so-called exoplanets, or planets outside our solar system.

The existence of the so-called exoplanets — planets outside our solar system — was announced at the European Southern Observatory/Center for Astrophysics, University of Porto conference in Porto, Portugal, according to a statement issued by the observatory.

The announcement was made by a consortium of international researchers, headed by the Geneva Observatory, who built the High Accuracy Radial Velocity Planet Searcher, or HARPS. The device can detect slight wobbles of stars as they respond to tugs from exoplanets’ gravity. That tactic, known as the radial velocity method, “has been the most prolific method in the search for exoplanets,” according to the European Southern Observatory statement.

The instrument detects movements as small as 3.5 km/hr (2.1 mph), a slow walking pace, the observatory said.

With the discovery, the tally of new exoplanets found by HARPS is now at 75, out of about 400 known exoplanets, the organization said, “cementing HARPS’s position as the world’s foremost exoplanet hunter.” The 75 planets are in 30 planetary systems, the European Southern Observatory said.

“HARPS is a unique, extremely high precision instrument that [is] ideal for discovering alien worlds,” Stephane Udry of Geneva University, who made the announcement on behalf of the international consortium that built the instrument, said in the observatory statement. “We have now completed our initial five-year program, which has succeeded well beyond our expectations.”
HARPS has also boosted the discovery of so-called super-Earths — planets with a mass a few times that of Earth. Of the 28 super-Earths known, HARPS facilitated the discovery of 24, the European Southern Observatory statement said. Most reside in multiplanet systems, with up to five planets per system.

Although only 32 were announced Monday, the team knows of many more exoplanets, although more observation is needed before they are formally announced and papers are written about them. “We have tons of them,” Udry said.

In return for building HARPS, the consortium was provided 100 observing nights per year over five years to search for exoplanets, one of the most ambitious searches ever implemented on a global basis, the European Southern Observatory said.

“These observations have given astronomers a great insight into the diversity of planetary system and help us understand how they can form,” team member Nuno Santos said in the statement.

The HARPS findings confirm the predictions of those who study planetary formation, Udry said. “Moreover, those models are also predicting even more … Earth-type planets.”

An important find for the study of planet formation was that three exoplanets were around stars that are metal-deficient, Udry said. Metal-deficient stars are thought to be less favorable for planet formation; however, planets the size of several Jupiters were found orbiting such deficient stars, the European Southern Observatory said.

In addition, the discovery gives “a very strong push” to projects attempting to find and study such exoplanets, Udry said.

According to its Web site, the European Southern Observatory is the foremost intergovernmental astronomy organization in Europe and describes itself as the “world’s most productive astronomical observatory. ” It is supported by 14 European countries

Tags: Extra Terrestrial, Planets, Space

Planet-hunters find bonanza of new solar systems

Posted on 04. Jun, 2007 by naresh in Space

Planet-seekers who have spotted 28 new planets orbiting other stars in the past year say Earth’s solar system is far from unique and there could be billions of habitable planets.

The most recent planet discoveries bring the number of known exoplanets — planets outside our solar system — to 236, the researchers told a meeting of the American Astronomical Society in Honolulu Monday.

“We are beginning to see that our home is not a rarity in the universe,” said Geoffrey Marcy, a professor of astronomy at the University of California Berkeley, who led the team.

“We are easily able to detect giant planets like Jupiter and Saturn around other stars. Most orbit far from the star like our own Jupiter and Saturn orbit from the sun,” Marcy said in a telephone interview.

“It’s a common structure among planetary systems.”

New techniques allow astronomers to detect planets that are not enormous although Earth-sized objects cannot yet be seen, said the researchers.

Four of the systems also have multiple planets, like Earth’s own with its sun, eight planets (Pluto was demoted from planet status) and smaller orbiting objects.

“We are finding that most stars have not just one planet but when we find one there is a second or a third or a fourth,” Marcy said.

“The … attribute which really has us the most excited is this new planet which we found three years ago,” Marcy said. The Neptune-like planet orbiting the star Gliese 436 has intrigued scientists because it appears to be covered with water — albeit rock-hard, hot water in a most un-Earthlike chemical state because of the intense pressures on the planet.

Earlier this month, Swiss and Belgian researchers imaged the star as this planet crossed between it and the Earth. The tiny change in the star’s light gave them the planet’s diameter and density.

“From the density of two grams per cubic centimeter — twice that of water — it must be 50 percent rock and about 50 percent water, with perhaps small amounts of hydrogen and helium,” Marcy said.

“Now we are very sure it has a rocky core and this giant thick envelope of water,” he added.

“This is why we are jumping out of our clothes. It is the first time we have determined the structure of one of these extrasolar planets. It is rocky like Earth but it has a lot of water which is the essential ingredient for life.”

This is almost certainly happening over and over again, Marcy said. Scientists had theorized this for decades but now the hard evidence is starting to pour in.

“Our Milky Way galaxy has 200 billion stars. I would estimate that 10 percent of them, perhaps, have planets that are habitable,” Marcy said.

“There are hundreds of billions of galaxies, all of which are more or less like our Milky Way Galaxy, which is tens of billions of planets like our own.”

There is one unusual property to our solar system: the nearly circular orbits of the planets, which gives a consistent dose of radiation from the Sun.

Other solar systems seen so far are not usually like this. “Most of the planets are not in circular orbits around the host star but in elongated ones called elliptical orbits,” Marcy said.

“We enjoy nearly constant temperatures throughout the year,” he added. “If the Earth got too close to the sun, the Earth would heat up, the water would boil off and that would be bad.” Too far, and it would freeze.

“An elongated orbit could not sustain life,” Marcy said.

A drawing of the Neptune-like planet orbiting star Gliese 436.

Tags: Planets, Space

Strong evidence of wet past on Mars

Posted on 04. Jun, 2007 by naresh in Space

The Mars rover Spirit has uncovered the strongest evidence yet that the planet used to be wetter than previously thought, scientists reported Monday.

The robot analyzed a patch of soil in Gusev Crater and found it unusually rich in silica. The presence of water would have been necessary to produce such a large silica deposit, scientists said.

“This is a remarkable discovery,” principal investigator Steve Squyres of Cornell University said in a statement. “It makes you wonder what else is still out there.”

Spirit previously found clues of ancient water in the crater through the presence of sulfur-rich soil, water-altered minerals and explosive volcanism. But the latest find is compelling because of the high silica content, researchers said, raising the possibility that conditions may have been favorable for the emergence of primitive life.

It’s unclear how the silica deposit formed. One possibility is that the soil mixed with acid vapors in the presence of water. Others believe the deposit was created from water in a hot spring surrounding.

The durable Spirit and its twin, Opportunity, have been working on overtime since completing their primary, three-month mission in 2004.

For eight months, Opportunity has explored the rim of Victoria Crater on the opposite side of the planet. Scientists are looking for a safe opening to send the rover in.

The mission is managed at NASA’s Jet Propulsion Laboratory in Pasadena.

A patch of Martian soil analyzed by Spirit is rich in silica — strong evidence the red planet was much wetter than it is now.

Tags: Mars, Planets, Space