Hot Jupiter KELT-16b Spirals To Death As It Orbits Extremely Close To Parent Star
An exoplanet dubbed KELT-16b may not survive for long because of its proximity to its star. The giant planet began its death spiral into its host star more than 2 billion years ago and may only have a few hundred thousand years left before it eventually gets destroyed.
KELT-16b orbits KELT-16, a star with 1.2 times the mass of the sun and is located about 1,300 light-years away from Earth. With the aid of the Kilodegree Extremely Little Telescope or KELT, which is composed of two telescopes (one in Arizona and another in South Africa), astronomers found that the planet is 2.75 as massive as Jupiter and 1.4 times as wide.
The planet is a hot Jupiter, a gas giant that circles its star closer than Mercury orbits the sun. Unlike the biggest planet in the solar system though, hot Jupiters orbit very close to their host star with an orbital period of less than 10 days. KELT-16b is the sixth planet that scientists have so far discovered to make a complete orbit around its star in less than one Earth day.
Scientists have recently proposed that hot Jupiters grow bigger as they age; however, they do not have substantial evidence to support this theory. Nearly 300 hot Jupiters have been discovered as of January this year.
Orbiting Very Close To Its Host Star
KELT-16b orbits its host star at a distance of about 0.02 astronomical units. Observations also revealed that a red dwarf star also orbits KELT-16 at a distance of at least 286 astronomical units.
Based on current models of how giant planets form, scientists think that KELT-16b may have once orbited its parent star much farther away, possibly at a distance of more than 5 astronomical units. The gravitational tugs from the red dwarf star though may have impacted the planet's orbit, causing it to get closer to the host star.
"The likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai-Lidov (KL) oscillations played a role in driving KELT-16b inward to its current precarious orbit," researchers wrote in their study, which was published in The Astronomical Journal on Feb. 7.
Tidal Forces To Destroy Giant Gas Planet In 550,000 Years
Because of its proximity to its star, the gas planet likely experiences extreme heat and powerful tides. Scientists think that the planet may have started its runaway spiral to death about 2.1 billion years ago and that tidal forces may tear it apart in 550,000 years.
"Most if not all hot Jupiters are likely to end up being tidally disrupted," said Keivan Stassun, from Vanderbilt University in Tennessee.
The regularity of the planet's orbit around the star helps scientists analyze the starlight that passes through the planet's atmosphere. The amount of light that the planet gets from the star and its size also make it easier to gather details about the planet. Analysis of the planet's orbit may shed light on the evolution of exoplanets.