Extrasolar Planets: April 2007

Astronomers find first habitable Earth-like planet, ESO

"Astronomers have discovered the most Earth-like planet outside our Solar System to date, an exoplanet with a radius only 50% larger than the Earth and capable of having liquid water. Using the ESO 3.6-m telescope, a team of Swiss, French and Portuguese scientists discovered a super-Earth about 5 times the mass of the Earth that orbits a red dwarf, already known to harbour a Neptune-mass planet. The astronomers have also strong evidence for the presence of a third planet with a mass about 8 Earth masses."

Members of NAI's Virtual Planetary Laboratory Alumni Team and their colleagues have a new paper in the current issue of Astrobiology. They present a critical discussion of M star properties that are relevant for the long- and short-term thermal, dynamical, geological, and environmental stability of conventional liquid water habitable zone (HZ) M star planets. [Source: NAI Newsletter]

Multidisciplinary work from members of NAI's SETI Institute Team and a host of collaborators across the NAI re-examines what is known at present about the potential for a terrestrial planet forming within, or migrating into, the classic liquidsurfacewater habitable zone close to an M dwarf star. Their new paper, published in the current issue of Astrobiology, presents the summary conclusions of an interdisciplinary workshop sponsored by NAI and convened at the SETI Institute in 2005. [Source: NAI Newsletter]

Differently colored plants may live on extra-solar planets, according to two new papers in the current issue of Astrobiology authored by members of NAI's Virtual Planetary Laboratory Alumni Team and their colleagues. They took previously simulated planetary atmospheric compositions for Earth-like planets orbiting various star types (including M stars), generated spectra, and found that photosynthetic pigments may peak in absorbance in the blue for some star types, and red-orange and near-infrared for others. Their results also suggest that, under water, organisms would still be able to survive ultraviolet flares from young M stars and acquire adequate light for growth - which greatly increases the scope for habitability in these systems. [Source: NAI Newsletter]

NAI Postdoctoral Fellow Sean Raymond leads a team of authors from NAI's University of Colorado, Boulder, and University of Arizona Teams, and Virtual Planetary Laboratory and University of Washington Alumni Teams in a new publication in Astrobiology. They present analysis of water delivery and planetary habitability in 5 high-resolution simulations forming 15 terrestrial planets. Their results outline a new model for water delivery to terrestrial planets in dynamically calm systems, which may be very common in the Galaxy. [Source: NAI Newsletter]

Search for Habitable Planets Outside Earth's Solar System in Astrobiology

"Which planets outside of Earth's Solar System are most likely to be capable of supporting life is a question that will be the focus of both a NASA-sponsored workshop later this year and a special collection of papers in the Spring 2007 (Volume 7, Number 1) issue of Astrobiology, a peer-reviewed journal published by Mary Ann Liebert, Inc."