This artist illustration shows the potential temperate planet Ross-128b, with its red dwarf parent star in the background.
One of the nearest exoplanets to Earth a decent home for life.
Ross-128b — which is only 11 light years from our planet — probably a rocky and temperate world, a new study suggests.
“Although Ross 128b is the Earth not two, and there is still much we don’t know about the possible geological activity, we were able to strengthen the argument that it is a temperate planet that may have liquid water on the surface,” lead author Diogo Souto, of the Observatório Nacional in Rio de Janeiro, Brazil, said in a statement. [ 10 Exoplanets That Could Host Alien Life ]
Ross-128b is excited and intrigued astrobiologists since the discovery of last year. The planet appears to circle in the ‘habitable zone’ of the star — that just-right range of distances where liquid water can exist on earth. (Ross-128b circles a small, dim red dwarf star, so the habitable zone is relatively close in; the planet completes one orbit every 9.9 days on Earth.)
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The first estimates also indicated that Ross 128b has a minimum mass of only 1.35 times that of Earth and therefore a good chance of being rocky, like our own planet.
The new study will not spoil the enthusiasm. The researchers analyzed Ross-128b the parent star, known as Ross 128, with the help of the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment (APOGEE), a spectroscopic instrument, installed on a telescope in New Mexico.
“The ability of APOGEE to measure near-infrared light, where Ross 128 is the brightest, was the key for this study,” study co-author Johanna Teske, of the Carnegie Institution for Science in Washington, D. C., said in the same statement . “It gave us the opportunity to have a number of fundamental questions about Ross 128b ‘Earth-like-ness.'”
The APOGEE data revealed that the abundances of certain key elements in Ross 128, including carbon, oxygen, magnesium, and iron. Because stars and their planets coalesce from the same huge cloud of raw materials, this information reveals several important characteristics about Ross 128b.
For example, the stellar abundances, combined with Ross 128b known minimum mass, suggesting that the planet radius is less than 1.7 times that of the Earth. That is the rough threshold that worlds have a significant gaseous envelope — which means that Ross 128b is likely to be rocky.
In addition, the red dwarf is observed to be iron-magnesium ratio indicates that Ross 128b of the core is greater than that of the Earth, the researchers said.
The team also determined that the temperatures on or in the vicinity of the “surface” of the star around 5,400 degrees Fahrenheit (3,000 degrees Celsius). The researchers used this information, together with Ross 128b of the radius and orbital distance, to find out how much solar energy that the planet receives, and therefore how warm it is likely.
The result? Ross-128b probably has an “equilibrium temperature of approximately 70 degrees Fahrenheit (21 ° C). This should not be taken as gospel, but of the planets temperatures are very dependent on the composition and the thickness of their atmosphere, and the nature of Ross-128b the air is a complete mystery.
The new study appeared last month in The Astrophysical Journal Letters .
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