Number of candidate exo-Earths reduced by Gaia data
Worlds without end: The number of candidate exo-Earths identified by Kepler has now been reduced based on data from Europe’s Gaia telescope.
To date, NASA’s prolific Kepler space telescope has discovered about 30 roughly Earth-size exoplanets in their host stars’ “habitable zone” — the range of orbital distances at which liquid water can likely exist on a world’s surface.
Or so researchers had thought. New observations by the European Space Agency’s (ESA) Gaia spacecraft suggest that the actual number is probably significantly smaller — perhaps between two and 12, NASA officials said today.
Gaia launched in December of 2013 to create an ultraprecise 3D map of the Milky Way. So far, this map includes position information for about 1.7 billion stars and distance data for about 1.3 billion stars, according to NASA officials. Gaia’s observations suggest that some of the Kepler host stars are brighter and bigger than previously believed, the officials added. Planets orbiting such stars are therefore likely larger and hotter than previously thought.
Being hotter and larger, the habitable zone for these stars shifts outward, placing the exoEarth’s outside the habitable zone.
Worlds without end: The number of candidate exo-Earths identified by Kepler has now been reduced based on data from Europe’s Gaia telescope.
To date, NASA’s prolific Kepler space telescope has discovered about 30 roughly Earth-size exoplanets in their host stars’ “habitable zone” — the range of orbital distances at which liquid water can likely exist on a world’s surface.
Or so researchers had thought. New observations by the European Space Agency’s (ESA) Gaia spacecraft suggest that the actual number is probably significantly smaller — perhaps between two and 12, NASA officials said today.
Gaia launched in December of 2013 to create an ultraprecise 3D map of the Milky Way. So far, this map includes position information for about 1.7 billion stars and distance data for about 1.3 billion stars, according to NASA officials. Gaia’s observations suggest that some of the Kepler host stars are brighter and bigger than previously believed, the officials added. Planets orbiting such stars are therefore likely larger and hotter than previously thought.
Being hotter and larger, the habitable zone for these stars shifts outward, placing the exoEarth’s outside the habitable zone.