An article to be published in “The Astronomical Journal” offers evidence that confirms the existence of the exoplanet Kepler-1658b almost ten years after the detection of its first traces by NASA’s Kepler space telescope, which made it the first candidate discovered in its mission. A team of researchers led by Ashley Chontos, a student at the University of Hawaii, reviewed the data collected after that first detection also using the technique of astroseismology to confirm that the planet actually exists. The results were also presented in recent days at the Kepler/K2 Science Conference held in Glendale, California.
The Kepler space telescope was launched exactly 10 years ago, on March 7, 2009, and the end of its mission was declared in October 2018. When its missions began, the first three planets detected were already known therefore the fourth, initially designated as KOI (Kepler Object of Interest) 4.01, became the first candidate that needed to be verified. The problem was that the estimate of its host star’s size were inaccurate and this led to the belief that it was a false positive, but almost 10 years later things have changed.
Ashley Chontos of the University of Hawaii re-analyzed the data collected on this exoplanet candidate as part of a university research project also using the technique of astroseismology. This made it possible to obtain a far more precise estimate of the star Kepler-1658’s size, a crucial step forward in verifying the candidate exoplanet. The result is that this star has a mass about 1.5 times the Sun’s but has a radius almost three times the Sun’s indicating that it’s in an advanced phase of its life.
Astronomer Dave Latham of the Smithsonian Astrophysical Observatory got involved in this research and is in fact one of the article’s authors. He’s one of the pioneers of exoplanetary science and a key figure behind the Kepler mission who in this specific case contributed together with his collaborators by providing spectroscopic data that helped confirm the existence of the planet Kepler-1658b.
The results of the analyzes indicate that the exoplanet Kepler-1658b is a hot or even ultra-hot Jupiter, since its orbit is very close to its star, at a distance from it which is only twice the star’s diameter and with a year of 3.85 Earth’s days. The planet’s mass was estimated around almost six times Jupiter’s while its size is just larger than Jupiter’s.
This confirmation is interesting because the star Kepler-1658 shows what the Sun will look like in the distant future and because few planets have been discovered orbiting such evolved stars but the reason for this scarcity is not clear. This case will be useful to understand the interactions between stars and planets, in particular phenomena such as planetary migrations that can bring gas planets closer to their stars and in some cases to be destroyed by them.
The case of the exoplanet Kepler-1658b is curious for the time it was needed to verify it. Ashley Chontos pointed out that this is a perfect example of why a better understanding of the stars that host exoplanets is important and that there are many treasures yet to be discovered in Kepler’s data. This space telescope really marked an era for exoplanet research and this research shows that astronomers are still learning how to exploit the collected data.