An international research team led by scientists from the US National Aeronautics and Space Administration (NASA) announced the discovery of 7 very hot planets, each of which is larger than Earth but smaller than Neptune, and is about 5,000 light-years away from Earth.
Planet hunter
According to the study, which was published in the Journal of Planetary Science, this rare star system was found during an ongoing inventory of data from NASA’s retired Kepler space telescope.
Kepler launched in 2009 with one goal: to discover Earth-sized planets orbiting other stars in the Milky Way Galaxy. After nine and a half years of operation, the telescope’s control system ran out of fuel, and NASA announced its retirement in October 2018. Meanwhile, Kepler observed 530,506 stars, and more than 2,500 planets were discovered.
Kepler observes the planets by observing the light emanating from the stars for a period of time. If this light decreases slightly and then rises again, this is an indication that one of the planets has crossed in front of the star. To understand this idea, imagine that you are holding between your fingers a small metal ball with a diameter of half a centimeter, for example. Then you extended your hands and passed this ball in front of the large lamp at the top of the room. Here you will notice that the light of the lamp decreased as the ball passed in front of it.
The same thing happens in the case of Kepler. When a planet crosses in front of the star, the star’s light decreases slightly, and consequently the size, duration, and frequency of the decrease can help determine the planet’s orbit, diameter, and sometimes the composition of its atmosphere.
An imaginative depiction of the seven planets discovered by the Kepler telescope (NASA)
Wonderful worlds
According to the new study, this star around which these seven planets revolve, which is called Kepler 385, is a sun-like star, but it is only about 10% larger in size, and 5% hotter than the sun.
The two inner planets in this star system are likely to be rocky like Earth, and may have a thin atmosphere, while the other five planets (which are larger) are expected to be surrounded by a thick atmosphere, according to an official press release issued by NASA.
In general, these planets are very close to their star, as the closest one makes a complete revolution around its star in approximately 3 and a half days, and the furthest of them makes a complete revolution around its star in about 86 days, that is, slightly less than Mercury’s revolution around the sun.
The largest of these planets in size is the planet called Kepler 385d, and its radius is two and a half times that of Earth, and it is the sixth in size around the star. As for the smallest in size, it is the closest to the star, and its radius is only about 1.2 times the diameter of Earth.
