Scientists have found a massive exoplanet that orbits a star about 500 light-years from the Solar System. The discovery is challenging ideas regarding planet formation, they say. It is not clear how they got there. George Zhou works in the Research School of Astrophysics and Astronomy (ANU) and said that they have discovered a tiny star with a large planet about the same size as Jupiter orbiting close to it. The exoplanet must have formed farther out, and then migrated in. However, our theories don’t understand how it happened. Over the past twenty years more than one ,800 star-expanding planet – a planet orbiting another star outside of our Solar System – has been found. HATS-6 is a huge exoplanet that orbits a star emitting one-twentieth of the Sun’s light. Its distance from the Sun to Mercury is one-tenth of Mercury. Image: anu.edu.au. The discovery was published in The Astronomical Journal (citation is below). Common but not well understood M-dwarf Stars This huge planet called HATS-6 orbits an M.dwarf star. It is the most frequent type of star in the Milky Way. Scientists don’t know much about M-dwarf star, despite their being numerous. Because they are cold, it is difficult to observe them. The Sun emits 20 times more light than HATS-6. Because of the dip in the brightness caused by the planet passing in front, the ANU Siding Spring Observatory small robot telescopes detected it. Astrophysicists suspected that there was another planet. Andrew Bayliss from ANU’s College of Physical & Mathematical Sciences asked T. G. Tan (an amateur astronomer who lives in Perth) to confirm the signal was a real planet. The Magellan Telescope is Chile’s largest telescope. George Zhou, Hawaiian Mauna Kea observatory. Image: anu.edu.au. Mr. Zhou stated that “T. G. Tan has been very helpful in our projects. “He was able catch the transit of planet HATS-6 from Perth after it had passed over our horizon. HATS-6 orbits the star approximately once every 3 days. Citation: HATS-6b, a Warm Saturn Transiting an Early M Dwarf star, and a Set Of Empirical Relationships for Characterizing K- and M Dwarf Planet hosts,” S. Ciceri and J. D. Hartman. The Astronomical Journal. Published 28 April 2015. DOI: 10. 1088/0004-6256/149/5/166.
A giant exoplanet around a star poses a challenge to ideas on planet formation.
