When Ross 128b was first discovered last fall, the Earth-sized exoplanet was hailed as a primary candidate in the search for alien life.
Located a mere 11 light-years away from our home planet, Ross 128b practically lies on our cosmic doorstep and is, in fact, the second closest exoplanet to Earth, after Proxima b, the Inquisitr reported at the time.
Ross 128b was also dubbed the "closest temperate world" ever discovered — although closer, at a distance of just 4.24 light-years from us, Proxima b is anything but temperate, as the planet is constantly battered by high amounts of radiation coming from its parent star, Proxima Centauri.
A little more than half a year after its discovery was announced, a fresh study published in The Astrophysical Journal Letters is bringing new evidence to support the claim that Ross 128b may have a temperate climate.
"Although Ross 128b is not Earth's twin, and there is still much we don't know about its potential geologic activity, we were able to strengthen the argument that it's a temperate planet that could potentially have liquid water on its surface," said study lead author Diogo Souto of the Observatório Nacional in Rio de Janeiro, Brazil.
According to the Carnegie Institution for Science in Washington, D.C., which was involved in the research, Ross 128b is nestled within the habitable zone, or Goldilocks zone, of its parent star — a cool red dwarf called Ross 128. This means that the exoplanet orbits the dim red dwarf close enough for liquid water to form on its surface but far enough so that it won't be torched by radiation.
Unlike Proxima b, which also orbits a red dwarf, Ross 128b has a much "quieter" parent star, which lacks the virulence exuded by Proxima Centauri. The Earth-sized exoplanet goes around its faint parent star once every 9.9 days and receives only about 1.38 times the amount of radiation that Earth gets from the sun, despite being 20 times closer to its star.
The new study took an in-depth look at the red dwarf Ross 128 in an effort to learn more about its sole and unique exoplanet. By observing the star with the Sloan Digital Sky Survey's (SDSS) Apache Point Observatory Galactic Evolution Experiment (APOGEE) — a spectroscopic instrument installed on a telescope in New Mexico, notes Space.com — the team managed to get a clearer picture of the star's chemistry, which in turn revealed crucial data about the chemical make-up of Ros 128b.
Commenting on the results, study co-author Johanna Teske of Carnegie stated that APOGEE was instrumental in unveiling how similar this exoplanet really is to Earth.
"The ability of APOGEE to measure near-infrared light, where Ross 128 is brightest, was key for this study. It allowed us to address some fundamental questions about Ross 128b's 'Earth-like-ness.'"The study examined Ross 128's abundance of a host of chemical elements (including carbon, oxygen, magnesium, aluminum, potassium, calcium, titanium, and iron) and uncovered it has a "near solar metallicity."
The element abundance in the red dwarf revealed many details about the exoplanet, given that both celestial objects formed from the same cloud of gas and dust.
The chemical composition of Ross 128 allowed researchers to establish that Ros 128b has a radius of less than 1.7 times that of Earth. This hints that the exoplanet is probably rocky and "lies below the pure-rock composition curve, suggesting that it contains a mixture of rock and iron," the authors wrote in their paper.
In addition, the iron-to-magnesium ratio found within the red dwarf indicated that its exoplanet — which weighs a minimum of 1.35 Earth masses — has a larger core than our planet.Judging by the temperature of the red dwarf, estimated at 5,400 degrees Fahrenheit (3,000 degrees Celsius) near the star's "surface," the researchers were able to calculate how much heat the exoplanet receives based on its radius and the distance at which it orbits Ross 128.
The measurements pointed out that the Earth-sized rocky planet likely has a temperate climate, with a balmy "equilibrium temperature" of about 70 degrees Fahrenheit (21 degrees C).
All these findings increase the chances that Ross 128b may be capable of hosting life as we know it.