Although mankind does not yet have conclusive answers to the question of whether or not we are alone in the cosmos, scientists are always looking for signs that could point to the presence of alien life.
What better place to start than by searching for additional planets like Earth that might be able to host life?
Exoplanet research has lately increased significantly, albeit the motivations for these studies vary amongst organizations. Some people only seek an explanation for the enigma of extraterrestrial life, while others seek a new planet to call home.
For those of you enthusiasts of exoplanets, we could suddenly have some excellent news. The Subaru Strategic Program, established in 2007 to produce outstanding scientific findings using the Subaru Telescope of Japan, has contributed to the identification of a super-Earth that is only 37 light-years away from Earth and is gliding along the periphery of a red dwarf star’s habitable zone.
The recently discovered Ross 508 planetary system is depicted schematically. The green region indicates the habitable zone (HZ), which is a region on the planet’s surface where liquid water can exist. A blue line represents the planetary orbit. The planet is expected to be closer than the HZ (solid line) during more than half of its orbit and within the HZ (dashed line) for the remainder. (Astrobiology Institute)
This rocky “super-Earth,” known as Ross 508b, has a mass almost four times that of our planet.
And on Ross 508b, a year only lasts for 11 Earth days! Since red dwarfs are much smaller than the Sun, which serves as the center of our solar system, this naturally indicates that its orbit is not very large.
However, because of their lesser diameters, their gravitational fields are likewise smaller than the Sun’s. Ross 508b therefore orbits it at a mere 5 million kilometer distance. Mercury is around 60 million kilometers from the Sun, as a point of comparison. How could it be considered livable given the close proximity of this super-Earth to its red dwarf? The orbit of Ross 508b is elliptical, so it essentially dips in and out of the habitable zone and isn’t constantly as near to the star.
This kind of planet could be able to keep water on its surface. There is still room for discussion and in-depth investigation over whether or not water or life genuinely flourishes there.
The connection between habitable planets and red dwarfs
Red dwarfs, which are smaller than the Sun and make up the majority of stars in the solar neighborhood, make up 75 percent of all stars in the Milky Way galaxy. They are therefore important targets in humanity’s search for alien life and nearby extrasolar planets.
Studying red dwarfs is difficult, though, because they are colder than other kinds of stars and emit less visible light.
The fact that this discovery was made by the Subaru Strategic Program using the infrared spectrograph IRD on the Subaru Telescope (IRD-SSP) makes it all the more remarkable. The team at the Astrobiology Center in Japan created IRD specifically to look for red dwarf-orbiting exoplanets like Ross 508b. It makes use of a technique called planet-hunting, which looks for tiny variations in a star’s velocity to infer the presence of a planet circling it.
It wouldn’t be a leap to think that the Subaru Telescope may provide us even greater prospects for planets that are capable of supporting life.
“It has been 14 years since the start of IRD’s development. We have continued our development and research with the hope of finding a planet exactly like Ross 508b,” said Tokyo Institute of Technology’s Professor Bun’ei Sato, the principal investigator of IRD-SSP.
