A team of astronomers has discovered a significant number of hot Jupiters inside the star cluster Messier 67. It seems like the giant exoplanets are more common in the star cluster than expected.

Hot Jupiters are gas giant planets, similar to Jupiter, that orbit outside the Solar System (exoplanets) to get closer to their host stars. Scientists have found out that these planets are more come frequent than expected in the cluster star Messier 67.

 

To achieve these results, researchers have used several telescopes, instruments and data from La Silla observatory located in Chile. Among the instruments used by the research team, it was included the HARPS spectrograph at the European Southern Observatory (ESO). Image Credit: Astronomy Now

To achieve these results, researchers have used several telescopes, instruments and data from La Silla observatory located in Chile. Among the devices employed by the research team, it was included the HARPS spectrograph at the European Southern Observatory (ESO). Image Credit: Astronomy Now

The Chilean, Brazilian, and European team led by Roberto Saglia at the Max-Planck-Institut für Extraterrestrische Physik in Garching, Germany and Luca Pasquini from ESO collected high-precision measurements of 88 stars in Messier 67. The Messier 67is a star cluster that is to be about the same age and composition as the Sun, at the same time, the solar system is thought to have arisen in the similar environmental conditions to those found in Messier 67.

As per Roberto Saglia, the team wanted to use an open star cluster sample to examine the properties of exoplanets and theories of planet formation. Saglia also added that they not only found high incidences of many stars hosting planets but also they discovered that the hot Jupiter must have been formed in a dense environment.

Uncovering Hot Jupiters

Hot Jupiters’ evidence was found in three of the 88 stars contained in Messier 67, which is translated into a 5 percent rate. The rate of hot Jupiters among stars outside of clusters is less than 1 percent, so, the rate found in Messier 67 exceeded the statistical estimation: “This is a striking result. The new results mean that there are hot Jupiters around some 5% of the Messier 67 stars studied — far more than in comparable studies of stars not in clusters, where the rate is more like 1%,” expressed Anna Brucalassi, lead author of the analysis of Messier 67 data collected by HARPS.

Scientists believe that the gas giant exoplanets might form far away from their stars and at a certain point of their evolution, they started to migrate closer to their host stars.

What remains in mystery for science if the cause of such migration. Researchers have been working on the answers to that enigma, but one of the hypotheses they have reached so far is that stellar flybys put away hot Jupiters from orbit, forcing them to get closer to their parent stars. Such assumption has not been proved yet.  

The findings of the research were published early this week in the journal Astrology & Astronomy.

Source: ESO