A Cool Stars 17 splinter session

Conveners: Eric Hilton (Univ. of Hawaii), Barbara Rojas-Ayala (AMNH)

Eric Gaidos (Univ. of Hawaii), Sebastien Lepine (AMNH), Andrew Mann (IfA)



We aim to bring together those that study the properties of M dwarfs and those that search (or plan to search) for planets around them, as well as the few that do both. We will have presentations from the exoplanet (the demand) and the M dwarf (supply) sides of the community, followed by what we expect to be intense discussion. There is a broad range of topics to be covered in this Splinter, but we all have the same goals in mind: what do we know and what do we need to know about M dwarfs to understand their planets, and how do we identify which M dwarfs are the most promising targets for exoplanet searches? The speakers have been asked to look to the future - new surveys, instruments, simulations, and prospects for the field in the next 10 years.

Schedule and Confirmed Speakers:

  1. 1.How many and which targets do exoplanet searches need? Xavier Bonfils (UJF-Grenoble)

  2. 2.The Solar Neighborhood: Who Are the Stars? Where Are the Planets? Todd Henry (Georgia State)

  3. 3.How precise do we need radii, masses, Teff of M dwarfs to properly characterize planets? Leslie Rogers (MIT)

  4. 4.Direct Measurements of M Dwarf Radii with an Eye on Exoplanets Kaspar von Braun (Caltech)

  5. 5.What properties of M dwarfs can we reliably infer from models? Christiane Helling (St. Andrews)

  6. 6.Planet formation theory and metallicity: what we need to know? Andrew Youdin (CfA)

  7. 7.Techniques for determining metallicity: Barbara Rojas-Ayala (AMNH)

Click here for Abstracts


M dwarf stars have become a "hot" topic in the field of "cool stars", in large part because of the interest in discovering planets, especially small planets, around them: smaller planets can be detected around stars with smaller radii (by the transit technique) or lower mass (by the Doppler technique). Planets can be very close to low luminosity M dwarfs, and thus detectable, but still be in the "habitable zone" where an Earth-like planet would have liquid water. M dwarfs were long sidelined by the bias of magnitude-limited surveys, or concerns about high levels of activity. Now, new instruments and an appreciation that many M dwarfs are equal or superior targets for planet searches compared to their solar-mass cousins, have placed them in the front and center of the exoplanet stage.

On the other hand, there is much we need to learn about M dwarfs, including the location of most of the nearest ones, the precise relationships between mass and radius, the relationship between spectral type and effective temperature, and how to determine their metallicity. Planet hunters need to know where to look, and how to scale the size of the surveys; determinations of the radius of a transiting planet are limited by the precision with which we know the radius of the host star; tests of planet formation theories involving metallicity are limited by how well we can measure metallicity, a non-trivial determination for M dwarfs.