Cool Stars 14 - Submitted Abstract # 139
This version created on 05 October 2006

M Dwarfs as Desirable Targets for Planet Search Surveys


Angelle Tanner, JPL/CIT

Here I will illustrate the advantages and disadvantages of focusing
different types of planet searches on M dwarfs with the goal of
illustrating that these stars may represent the best targets for
detecting super-Earth mass planets from the ground.  These stars have
been desirable targets for both radial velocity and astrometry targets
since their reduced mass results in larger signals.  There are now
both radial velocity and astrometric programs devoted to searching to
planets with three new planetary systems discovered to date – GL876,
GL581, and GL436.  The planets around these stars have some of the
lowest masses discovered to date.  Ironically, the fact that M dwarfs
are faint makes them ideal targets for both transit and direct imaging
programs due to a reduction in the contrast level between the star and
planet.  Larger telescopes and improvements in imaging capabilities
are making M dwarfs more viable targets for direct imaging and transit
surveys.  It is believed that a dedicated transit M dwarf survey could
result in the detection of superEarths.  In addition to the
observational arguments, I will address the theoretical expectations
for the population of planets around M dwarfs given current planet
formation models.  The observed frequency of planets around M dwarfs
can distinguish core accretion or disk instability as the dominant
planet formation mechanism around low mass stars.  Finally, I will
discuss the potential for detecting terrestrial mass planets around
the nearest M dwarfs with SIM PlanetQuest.

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