Stars’ surface gravity predicts how habitable a planet is according to a newly published study featuring in the Science Advances journal. The research, conducted by an international scientific team, was led by professor Thomas Kallinger of the University of Vienna in collaboration with professor Jaymie Matthews with the University of British Columbia.
The joint scientific team, comprising astronomers from Australia, Germany and France as well, has brought about a novel method of determining the habitability prospect of an exoplanet. Surprisingly, the method doesn’t involve research based on the exoplanet itself. Rather, it looks at the star the planet is orbiting. Simply put, stars’ surface gravity predicts how habitable a planet is. According to the research team, measuring the pull of gravity at a star’s surface holds the key to understanding the habitability prospect of an exoplanet.
The newly developed method is dubbed ‘the autocorrelation function timescale technique’. Alternatively, timescale technique is sufficient to reference the newly developed method. The timescale technique makes use of data collected by NASA’s Kepler missions as well as Canada’s MOST satellite. The brightness of distant stars is the basis of the timescale technique. Detecting brightness variations is also key to measuring the star’s surface gravity.
The surface gravity indicates the radius and mass of the respective star. Assuming we could stand on the solid surface of a star, our weight would differ from star to star. The same happens from planet to planet. On the Sun for instance, your weight would increase 20 fold. On a red star the size of our Sun you’d weigh 50 times less. That is because red stars are dying. Thus, they have a weaker surface gravitational pull.
With this in mind and using satellite data, the research team proposes that a distant star’s surface gravity can be used to calculate the mass and radius. The timescale technique has an accuracy of four percent when applied to very distant and faint stars. Nonetheless, the timescale technique can be successfully used to understand the habitability prospect of an exoplanet orbiting one of these distant stars.
According to professor Matthews knowing the planet implies knowing the star. The novel technique can determine the mass and radius of the star, its brightness and surface gravity. Based on this data, the possibility that an exoplanet may harbor water oceans and life under the right temperature conditions can also be studied.
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