The new planet dubbed Proxima C orbits Proxima Centauri, a star system located some 4 light years from Earth. You may remember the Proxima Centauri system from 2016 when astronomers discovered a planet they nicknamed the SECOND Earth.
In August of 2016, astronomers announced the discovery of Proxima b, a potentially habitable orbiting Proxima Centauri, the star closest to the Solar System—located a mere four light years from Earth.
Proxima Centauri is about one-seventh the actual diameter of the Sun. It has a mass about an eighth of the Sun’s mass (M☉), and its average density is about 40 times that of the Sun
The discovery of Proxima B got astronomers very excited, they believed they discovered an alien world extremely similar to Earth, capable of sustaining life as we know it. Some even called Proxima B the SECOND Earth or Earth’s twin.
Now, a new data analysis has shown the presence of another alien world orbiting Proxima Centauri: Proxima C.
Using the High Accuracy Radial velocity Planet Searcher (HARPS), a high-precision spectrograph installed on ESO’s 3.6-meter telescope at the La Silla Observatory in Chile, astronomers involved in the Red Dots project have found what they believe could be the signature of another exoplanet orbiting Proxima Centauri.
The ongoing Red Dots campaign, is a search for planets around our nearest three red dwarf stars: Proxima Centauri, Barnard’s Star, and Ross 154.
Just as a star influences the planets by means of gravity, the planets also do the same with their star, causing the star to “totter” and change the wavelength of its brightness in a very small but measurable amount. By analyzing these repetitive and predictable changes, astronomers are able to infer the presence of a planet.
This is awesome, mostly because experts still believe Proxima B—the alien world discovered in 2016—could sustaining life as we know it.
The discovery of Proxima C raises hopes of finding another potentially habitable world outside our solar system.
The following chart shows the 2016 data that confirmed the existence of Proxima b (top left), where you can see the curve representing the star’s wobble, with a regular pattern of radial velocity change that repeats every 11, 2 days. In the new measurements of HARPS (top right), astronomers detected another, very similar signal that infers the existence of Proxima C, another alien world orbiting the Proxima Centauri system.
As noted by Astrobiology, the new data once again confirms Proxima B’s signal (in yellow), but also includes additional data patterns — visible here as a downward slope in both the 2016 and 2017 data points — hinting that there may be more to be discovered. To make a firmer statement on what is causing these patterns, astronomers need to use quantitative mathematical tools.
To ascertain whether it is a planet, astronomers made use of quantitative mathematical tools, such as a periodogram (shown at the bottom of the image above), which looks for repetitive signals in the data – graphed as prominent peaks – which indicate the presence of a planet.
The first signal (white) corresponds to Proxima b. The second set of possible periods (in red), of about 200 days, would be the hypothetical planet Proxima c.
The Red Dots exoplanetary search campaign will continue until the end of September, so the next few weeks will be critical to confirm or discard this data.