Looking for Earths by
looking for Jupiters
Washington,
D.C.— In the search for Earth-like
planets, it is helpful to look for clues and patterns that can help scientist
narrow down the types of systems where potentially habitable planets are likely
to be discovered. New research from a team including Carnegie’s Alan Boss
narrows down the search for Earth-like planets near Jupiter-like planets. Their
work indicates that the early post-formation movements of hot-Jupiter planets
probably disrupt the formation of Earth-like planets.
Their work is published the
week of May 7 by Proceedings of the National Academy of Sciences.
The team, led by Jason Steffen
of the Fermilab Center for particle Astrophysics, used data from NASA’s Kepler
mission to look at so-called “hot Jupiter” planets—those roughly Jupiter-sized
planets with orbital periods of about three days. If a Jupiter-like planet has
been discovered by a slight dimming of brightness in the star it orbits as it
passes between the star and Earth, it is then possible—within certain
parameters—to determine whether the hot-Jupiter has any companion planets.
Of the 63 candidate hot Jupiter
systems identified by Kepler, the research team did not find any evidence for
nearby companion planets. There are several possible explanations. One is that
there are no companion planets for any of these hot Jupiters. Another is that
the companions are too small in either size or mass to be detected using these
methods. Lastly it is possible that there are companion planets, but that the
configuration of their orbits makes them undetectable using these methods.
However, when expanding the
search to include systems with either Neptune-like planets (known as “hot
Neptunes”), or “warm Jupiters” (Jupiter-sized planets with slightly larger
orbits than hot Jupiters), the team found some potential companions. Of the 222
hot Neptunes, there were two with possible companions, and of the 31 warm
Jupiters, there were three with possible companions.
“The implications of these
findings are that systems with Earth-like planets formed differently than
systems with hot Jupiters,” Boss said. “Since we believe that hot Jupiters
formed farther out, and then migrated inward toward their stars, the inward
migration disrupted the formation of Earth-like planets. If our sun had a hot
Jupiter, we would not be here.”
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Funding for the Kepler
mission is provided by NASA’s Science Mission Directorate. Support for some
of the scientists was provided by NASA via the Kepler Participating Scientist
program and Hubble Fellowship grants.
The Carnegie Institution for Science (carnegiescience.edu) is a private,
nonprofit organization headquartered in Washington, D.C., with six research
departments throughout the U.S. Since its founding in 1902, the Carnegie
Institution has been a pioneering force in basic scientific research. Carnegie
scientists are leaders in plant biology, developmental biology, astronomy,
materials science, global ecology, and Earth and planetary
science.
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