(UPI) October 8, 2013 - Finding
life on distant exoplanets may be more difficult than scientists thought,
researchers from China, the United Sates and Argentina said Monday.
Recent observations of several planet-hosting M dwarf stars –the focus of current efforts to find Earth-like planets—showed ultraviolet properties of the small stars are quite different from those of the sun, which could further complicate the search for alien life, the researchers told a meeting of the American Astronomical Society Division form Planetary Sciences in Denver.
That
could complicate the search for chemical signs of life, they said.
Feng
Tian, a professor at Tsinghua University,
and his U.S. and Argentine colleagues have shown that the atmospheres of
a hypothetical habitable planet around such a star could build up significant
levels of oxygen –one possible “signature” for alien life –even in the absence
of any such life.
“Before
we can claim the discovery of life on exoplanets, we have to examine the stars
harboring these planets more carefully”! the researchers said.
Other
scientists agreed.
“The
authors of this paper make an important point regarding the confidence we could
have in the detection of O2 simultaneously with H2O and CO2, as a biosignature
in the spectrum of an Earth-like exoplanet around an M star”, Alain Leger of
the Institute d’Astrophysique Spatiale at University of Paris said.
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