Voila! Scientists at Harvard-Smithsonian Center for Astrophysics (CfA) found three new exoplanets orbiting its host star about 100 light-years away from our solar system. By using advanced technology and transit method, scientists were able to discover the radii of these three exoplanets and classify them as super-Earths. Astronomers and researchers have long been searching for exoplanets with a similar atmospheric composition to Earth. There are certain conditions to be met in order for a planet to become an ‘exoplanet’ such as it must orbit around a host star and must be in a ‘habitable zone’ and others.
The scientists at CfA found the three exoplanets orbiting around their host star named “GJ9827” which is one of the few stars that are known to have several transiting terrestrial-sized exoplanets categorized for atmospheric characterization. The three exoplanets have radii of 1.6, 1.3, and 2.1 Earth-radii respectively which makes them super-Earths. According to its definition, super-Earths are those planets which have a mass larger than Earth but smaller than Neptune’s. According to researcher Joseph Rodriguez of CfA, out of the three exoplanets, two are interesting citing its radii falls between 1.5 and 2.0 Earth-radii. This is because, at this range of radii, the planet’s composition changes from rock to gaseous which is as per expectations. The researcher also pointed out how these exoplanets are among very few that have been discovered yet.
Scientists used transit method to determine the orbit of these exoplanets and found out that these planets revolve around its host star with a period of 1.2, 3.6, and 6.2 days respectively. However, due to its close proximity to its parent star, the temperature at these planets are extremely hot at 1,172,811 and 680 degree Kelvin. Further, future observations with respect to these exoplanets will help the scientists get a clearer picture of the atmosphere of these super-Earths that resides over 100 light-years away from our Solar System. To put things into perspective, this is the distance covered by light traveling at its speed over a period of 100 years.
According to the study published in ‘The Astronomical Journal’, there are over 3,500 confirmed candidates classified as exoplanets. One of the techniques used to determine these planets is called transit method where astronomers register a dip in the light cast by planets revolving around a star. This method gives details about the orbit period of that planet, its radius, and mass. Moving on to the chemical composition of the atmosphere, a similar method is used where scientists examine the depth of transits registered at a different wavelength which gives an overview about the temperature and the chemical composition of the planet’s atmosphere.