Toronto, Jan 10 (PTI) Exoplanets orbiting the same startend to have similar sizes and a regular orbital spacing,according to a study.
This pattern, revealed by observations of planetarysystems discovered by the Kepler Telescope, could suggest thatmost planetary systems have a different formation history thanthe solar system, researchers said.
They used the W M Keck Observatory on Maunakea in Hawaiito obtain high-resolution spectra of 1,305 stars hosting 2,025transiting planets originally discovered by Kepler.
From these spectra, the researchers measured precisesizes of the stars and their planets.
Published in The Astronomical Journal, the study led byastrophysicist Lauren Weiss from University of Montral inCanada focused on 909 planets belonging to 355 multi-planetsystems.
These planets are mostly located between 1,000 and 4,000light-years away from Earth.
Using a statistical analysis, the team found twosurprising patterns - that exoplanets tend to be the samesizes as their neighbours.
If one planet is small, the next planet around that samestar is very likely to be small as well, and if one planet isbig, the next is likely to be big.
They also found that planets orbiting the same star tendto have a regular orbital spacing.
"The planets in a system tend to be the same size andregularly spaced, like peas in a pod. These patterns would notoccur if the planet sizes or spacings were drawn at random,"said Weiss.
The similar sizes and orbital spacing of planets haveimplications for how most planetary systems form, researcherssaid.
In classic planet formation theory, planets form in theprotoplanetary disk that surrounds a newly formed star.
The planets might form in compact configurations withsimilar sizes and a regular orbital spacing, in a mannersimilar to the newly observed pattern in exoplanetary systems.
However, in our solar system, the inner planets havesurprisingly large spacing and diverse sizes.
Abundant evidence in the solar system suggests thatJupiter and Saturn disrupted our system's early structure,resulting in the four widely-spaced terrestrial planets wehave today, researchers said.
That planets in most systems are still similarly sizedand regularly spaced suggests that perhaps they have beenmostly undisturbed since their formation, they said. PTI SARSAR.
This is unedited, unformatted feed from the Press Trust of India wire.