University of Texas at Arlington
Press Release
August 15, 2003
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Habitat in Space
What would happen if we were to relocate the Earth into another planetary
system? Would life still be possible? In the planetary system of 47 Ursae
Majoris, which shows strong similarities to our own solar system, there is in
fact a habitable zone. These findings were published in the recent issue of the
International Journal of Astrobiology by scientists from The University of Texas
at Arlington (UTA) and the Potsdam Institute for Climate Impact Research, Potsdam,
Germany.
Dr. Manfred Cuntz from the University of Texas at Arlington (UTA) and
Drs. Siegfried Franck, Werner von Bloh, and Christine Bounama from the
Potsdam Institute for Climate Impact Research examined the planetary system
47 Ursae Majoris (47 UMa). This system is located approximately 45 light-years
from Earth in the constellation Big Dipper (or Greater Bear; Ursae Majoris),
and contains a solar-mass star.
So far, two giant planets, comparable to Jupiter and Saturn, have been discovered
in this system. They play an important role, as they shield the inner realm of the
planetary system from the impacts of comets and asteroids. Such giant planets,
however, can also disturb the orbits of other planets, including Earth-like planets.
The scientists looked at the following problem: In order to be located in the
so-called habitable zone, an Earth-like planet in the system 47 UMa has to orbit its
central star at a suitable distance. Habitable means that photosynthesis-based life
forms can exist on the surface of the planet. Additionally, the orbit of such a
planet must remain stable over a timespan of biological significance.
The scientists discovered that the chances for a habitable planet are especially
good if the planet's surface is covered to a significant extent by water. Such
planets are referred to as waterworlds. If it were located within the system 47 UMa,
the Earth - a waterworld by virtue of its 2/3 surface covered by water - would at
1.2 times the distance Earth-Sun to its central star, be able to exist on a stable
orbit in the habitable zone. These findings have brought scientists a step closer
to finding an Earth twin within the Milky Way.
The International Journal of Astrobiology is a peer-reviewed publication of
Cambridge University Press. It was founded in 2001 to provide a journal
able to accept papers from the burgeoning field of astrobiology.
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Contact:
Prof. Manfred Cuntz
Department of Physics
Science Hall, Box 19059
University of Texas at Arlington
phone: 817-272-2467
fax: 817-272-3637
email: cuntz@uta.edu
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Original article:
Franck, S., Cuntz, M., von Bloh, W., and Bounama, C. (2003). The habitable
zone of Earth-mass planets around 47 UMa: results for land and water worlds.
International Journal of Astrobiology 2 (1), 35-39.