6 items with the tag “m dwarfs

  • Detection of Planets Around M-Dwarfs
    NAI 2009 University of Hawaii, Manoa Annual Report

    In the studies of extrasolar planets, the nearest stars are of particular importance. We have started a survey of nearby M dwarfs in search of terrestrial planets.Our program has been responsible for the discovery of many planets around M dwarfs for the past several years, including the most recent one which is a Saturn-mass object. Our project is continuing and we expect more discovery of small planets in the next year.

    ROADMAP OBJECTIVES: 1.2
  • Stellar Effects on Planetary Habitability
    NAI 2009 VPL at University of Washington Annual Report

    Habitable environments are most likely to exist in close proximity to a star, and hence a detailed and comprehensive understanding of the effect of the star on planetary habitability is crucial in the pursuit of an inhabited world. We model how stars with different masses, temperatures and flare activity affect the habitability of planets. We also address the effect that tides between a star and a planet have on planetary habitability, including the power to turn potentially habitable planets like Earth into extremely volcanically active bodies like Io.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 4.1 4.3 5.3 6.1 7.2
  • Detection of Terrestrial Planets Around M Stars
    NAI 2010 University of Hawaii, Manoa Annual Report

    We have carried out an extensive search for small extrasolar planets around M stars in the solar neighborhood. Our search is focused on planets in the habitable zone. We have been able to detect 4 planets around M stars, among which an Earth-like planet in the habitable zone of star GL 581.

    ROADMAP OBJECTIVES: 1.2
  • Stellar Effects on Planetary Habitability
    NAI 2010 VPL at University of Washington Annual Report

    Habitable environments are most likely to exist in close proximity to a star, and hence a detailed and comprehensive understanding of the effect of the star on planetary habitability is crucial in the pursuit of an inhabited world. We looked at how the Sun’s brightness would have changed with time. We also model how stars with different masses, temperatures and flare activity affect the habitability of planets, including looking at the effect of a very big flare on a planet’s atmosphere and surface. We find that a planet with an atmosphere like Earth orbiting around a cool red star is fairly well protected from UV radiation, but particles associated with the flare can produce damaging chemistry in the planetary atmosphere that severely depletes the planet’s ozone layer.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 4.3 5.3 6.1 7.2
  • Stellar Radiative Effects on Planetary Habitability
    NAI 2011 VPL at University of Washington Annual Report

    Habitable environments are most likely to exist in close proximity to a star, and hence a detailed and comprehensive understanding of the effect of the star on planetary habitability is crucial in the pursuit of an inhabited world. We looked at how the Sun’s brightness would have changed with time. We used models to study the effect of one very big flare on a planet with a carbon dioxide dominated atmosphere, like the early Earth’s, and found that these types of planets are well protected from the UV flux from the flaring star. We have also looked at the first quarter of Kepler data to study flare activity on “ordinary” cool stars, that have not been preselected for their tendency to have large flares. We find that these cool stars fall into two categories: stars that have long duration flares of several hours, but flare less frequently overall, and stars that have short duration flares, but more of them. In future work we will explore the comparative effect on a habitable planet of these two patterns of flaring activity.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 4.3 7.2
  • Stellar Radiative Effects on Planetary Habitability
    NAI 2012 VPL at University of Washington Annual Report

    Habitable environments are most likely to exist in close proximity to a star, and hence a detailed and comprehensive understanding of the effect of the star on planetary habitability is crucial in the pursuit of an inhabited world. We looked at how the Sun’s brightness would have changed with time providing wavelength-dependent scaling factors for solar flux anywhere in the solar system from 0.6 to 6.7Gyr. Extrasolar planetary systems can only be determined through studying the host star; therefore we have also worked on determining the ages of Kepler planet host stars. We have constructed far ultraviolet to mid-infrared stellar spectra for 44 stars for being used as input in climate and photochemical models that are applied for determining habitable zones and possible characteristics of habitable planets. We have looked into the effect of methane (CH4) and hydrogen (H2) on the outer edge of the habitable zone for F, G, and M stars. We have studied the effect of host star stellar energy distribution (SED) and ice-albedo feedback on the climate of extrasolar planets.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 4.3 7.2