Hawaii, Gatra.com- Scientists found a ‘Super Earth’ exoplanet four times as massive as ours orbiting a star 36.5 light-years away. The ‘big earth’ is called Ross 508b. Research shows the planet is a rocky world rather than a gas. Daily Mail3/6.
Ross 508b orbits its parent star, a faint red dwarf in the habitable zone (life) every 10.75 days. That’s much faster than Earth’s 365-day orbit, but Ross 508b orbits a star much smaller and fainter than our sun.
Despite being in the ‘Goldilocks’ zone – where it’s neither too hot nor too cold for liquid water to exist – experts think it may not be as habitable for life as we know it.
But based on what is known about the planet’s mass limit, the newly identified world is most likely terrestrial, or rocky, in the same way as Earth, not gas.
Ross 508b was discovered by an international team of astronomers using the Japan Subaru Telescope National Astronomical Observatory in Hawaii.
It has been described in a paper led by astronomer Hiroki Harakawa, of the Subaru Telescope, and is the campaign’s first exoplanet.
Ross 508b orbits a nearby M dwarf star known as Ross 508, hence why it was given that name.
A ‘SuperEarth’ is a planet that is more massive than ours but does not exceed the mass of Neptune. Although the term refers only to the mass of the planet, it is also used by experts to describe a planet larger than Earth but smaller than the so-called ‘mini-Neptune’.
‘We show that the M4.5 Ross 508 dwarf has a significant RV periodicity at 10.75 days with possible aliases at 1.099 and 0.913 days,’ the researchers said.
‘This period has no pairing in photometry or indicators of stellar activity, but fits perfectly into the Keplerian orbit due to the new planet, Ross 508b.’
Ross 508, with 18 percent of the mass of our sun, is one of the smallest and faintest stars with an orbiting world that has been discovered using radial velocities.
The primary technique for finding exoplanets is the transit method, which was used by NASA’s exoplanet-hunting telescope TESS and earlier Kepler.
This involves an instrument gazing at the stars and looking for the regular dimming of their light caused by objects orbiting between Earth and the star.
Astronomers then use the depth of transit to calculate the object’s mass, with the larger the light curve the bigger the planet.
A total of 3,858 exoplanets have been confirmed with the help of this method. But another technique is radial velocity, which is also known as the wobble or Doppler method.
It can detect the ‘wobble’ in the star caused by the gravitational pull of an orbiting planet.
The wobble also affects the light coming from the star. As it moves toward Earth, the visible light shifts toward the blue part of the spectrum and, as it moves away, the visible light shifts toward the red.
The new discovery suggests that future radial velocity surveys in infrared wavelengths have the potential to reveal a large number of exoplanets orbiting dim stars.
‘Our findings suggest that the search for near-infrared RVs could play an important role in finding low-mass planets around cool M dwarfs like Ross 508,’ the researchers write in their paper.
This research has been published in Publications of the Astronomical Society of Japanand is available on arXiv .