December 6, 2011
Astronomers Launch Online Database Of Habitable Planets
Only 15 planets and 30 moons could potentially support alien life, according to a new online catalog of habitable planets launched by astronomers on Monday.
The Habitable Exoplanets Catalog (HEC) website describes the project as "an online database for scientists, educators, and the general public focused on habitable exoplanets discoveries.""The catalog uses various habitability indices and classifications to identify, rank, and compare exoplanets, including their potential satellites, or exomoons," the HEC homepage also says, adding that the information will be "updated as new results are available."
Scientists created the Internet database in order "to make sense of the ever-rising number of distant worlds that researchers have spotted with modern telescopes," Guardian Science Correspondent Ian Sample said. "They believe the database will help astronomers, and others with an interest, to compare faraway worlds and keep tabs on the most habitable ones as researchers discover them."
According to the HEC database as of Monday evening, only two planets and 28 moons out of 707 confirmed exoplanets were described as habitable and 14 planets and six moons out of 1,235 potential candidates, waiting for confirmation from NASA's Kepler space telescope, meet the criteria.
The catalogue also includes a list of 16 planets, ranked by their similarity to our world according to a scale known as the Earth Similarity Index (ESI). Topping the list is the class M mesoplanet KOI 736.01, followed by KOI 494.01, KOI 784.01, KOI 610.01, and KOI 947.01.
The ESI ranks planets based on their similarity to our world in terms of mass, radius, temperature and probability of having an atmosphere. It is one of three scales used by the developers of the database in their measurements. The others, according to Sample, are the habitable zone distance (the planet's position in regards to the potential for liquid water formation) and the global primary habitability (whether or not surface temperatures are suitable for the growth of plants and phytoplankton).
"The catalogue gives high scores for habitability to two confirmed planets," Sample said. "The first, Gliese 581d, is among several that circle one of Earth's nearest stars, a cool red dwarf around 20 light years away in the constellation Libra. The planet is about six times as massive as Earth."
"The second planet, HD85512b, orbits a star 36 light years away in the constellation Vela. It is more than three times as heavy as our own planet," he added. "Most of the planets astronomers have found are gas giants like Jupiter that are in close orbits around their stars."
The HEC also includes information on each planet's location, their probably masses, and the type and age of the star that they orbit, the Telegraph noted.
"I hope this database will help increase interest in building a big space-based telescope to observe exoplanets directly and look for possible signatures of life," Jim Kasting, a student of planetary habitability at Penn State University, told Sample.
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