New Insight for the Discovery of Hospitable Planets
A team of international astrophysicists led by a researcher at the University of Vienna have devised a method to measure the surface gravity of stars that were originally too distant to compute accurate measures for. With this new insight, scientists can determine if planets in their orbit could be hospitable to life.
The team calculated the surface gravity of stars that are too distant to study with conventional methods by looking at the slight variations in their brightness, which is caused by convection and surface turbulence. Gravity is crucial to many aspects of astrophysics, as it provides clues to the properties of stars, such as their mass and radius, and to the properties of planets in their orbits that might make them habitable. With these facets of the star known, astrophysicists are then able to determine if a planet orbiting the star is the correct size and temperature to host warm water oceans and life.
We need to know the size of the star because the size of an exoplanet is measured relative to the size of its parent star. Without the foreknowledge of the star’s size, you could find a planet around a star that you think is like the Sun but is actually a giant, and probably fool yourself into thinking you’ve found a habitable Earth-sized world.
To determine the gravitational pull of distant stars, the researchers used data of star brightness collected from Canada’s MOST and NASA’s Kepler satellites. Since its launch in 2009, Kepler has already discovered around 1,000 planets, a dozen of them less than twice the size of Earth and residing in the habitable zone of their host stars, which means that these planets orbit their host stars at the right distance to make them neither too hot nor too cold to contain liquid water. Astronomers believe the presence of water on planets is critical to life, along with other materials and gases that are required.
The team of astrophysicists behind the latest gravity-measuring technique believes that it will help future exoplanet surveys to correctly characterize the planets they find, hopefully bringing efficiency and consistency to the search for life.