Astronomers using a new technique may not only have found a super-Earth at a neighboring star, but they may have also imaged it directly. And it can be nice and cozy in the habitable area around Alpha Centauri.
It is much easier to see giant planets than planet-sized planets. No matter what detection method is used, larger planets are simply a larger needle in the cosmic haystack. But in general, astronomers are very interested in planets similar to Earth. And it’s much harder to find it.
We thought we would have to wait for the ultra-powerful telescopes currently under construction before we could look directly at exoplanets.
Facilities such as the giant Magellanic telescope and the European extraordinarily large telescope will exert the observational power of the exoplanet.
But a team of researchers has developed a new technique that can do the job. They say they have pictured a possible planet under Neptune / super-Earth orbiting one of our closest neighbors, Alpha Centauri A.
The team made their observations in an article in Nature communication titled “Imaging low-mass planets within the habitable zone of α Centauri.” The lead author is Kevin Wagner, an astronomer and Sagan Fellow at the University of Arizona.
While astronomers have previously found low-mass exoplanets, they have never seen their light. They watched the planets reveal themselves by pulling at their stars. And they watched as the light of the stars that housed these planets dropped as the planet passed in front of the star.
But they have never portrayed one directly. Until now, maybe.
This new detection method comes down to infrared. One of the challenges of imaging exoplanets on Earth in infrared is to distinguish the light of an exoplanet when the light is washed away by the star’s background infrared radiation.
Astronomers can search for exoplanets in wavelengths where the background of infrared is reduced, but in the same wavelengths moderate Earth-like planets are faint.
One method is to look in the near infrared (NIR) part of the spectrum. In NIR, the thermal glow of the planet is not so washed out by the star. But the starlight is still dazzling and millions of times brighter than the planet. Just looking at the NIR is therefore not a total solution.
The solution may be the NEAR (New Earths in the AlphaCen Region) tool used in this research. NEAR is mounted on the ESO (European Southern Observatory) Very Large Telescope (VLT) in Chile. It works with the VISIR instrument, also on the VLT. The group behind NEAR is the Breakthrough Watch, part of Yuri Milner’s Breakthrough Initiatives.
The NEAR instrument not only observes in the desired part of the infrared spectrum, but also uses a corona graph.
The Breakthrough group thought that the NEAR instrument used on an 8-meter ground telescope would allow better observations of the Alpha Centauri system and its planets.
Therefore, they built the instrument in collaboration with the ESO and installed it on the Very Large Telescope.
This new finding comes as a result of 100 hours of cumulative observations with NEAR and the VLT.
“These results,” the authors write, “demonstrate the feasibility of depicting rocky habitable zone exoplanets with current and emerging telescopes.”
The 100-hour commissioning was intended to demonstrate the power of the instrument.
According to the team, the NEAR tool, based on about 80 percent of the best images from the run, is an order of magnitude better than other methods of ‘…’ hot, sub-Neptune planets in much of observe the habitable area of α Centauri A. . “
They may have also found a planet. “We are also discussing a possible detection of exoplanet or exosodiac disc around Centauri A,” they write. “However, an instrumental artifact of unknown origin cannot be ruled out.”
This is not the first time that astronomers have found exoplanets in the Alpha Centauri system.
There are some confirmed planets in the system, and there are other candidates as well.
But none of them are directly depicted as this new potential planet, with the placeholder name C1, and the first potential detection around the M dwarf in the system, Proxima Centauri.
Follow-up observations should confirm or cancel the discovery.
It’s exciting to think that an exoplanet with a hot Neptune class could orbit a sunny star in our nearest neighboring galaxy. One of the goals of the breakthrough initiatives is to send light sailing spacecraft to the Alpha Centauri system and take a closer look at us.
But this prospect is out of reach for now. And in some ways, this discovery is not so much about the planet, but about the technology that has been developed to detect it.
The vast majority of the discovered exoplanets are giant planets similar in mass to Jupiter, Saturn and Neptune. It’s the easiest to find. But as humans from Earth, we are primarily interested in planets like our own.
Beautiful planets in a star’s habitable zone make us excited about life prospects on another planet. But they can also tell us a lot about our own solar system and how solar systems in general form and develop.
If C1 does turn out to be a planet, the breakthrough group will succeed in a major effort. They are the first to detect an earthy planet by direct imaging.
Not only that, but they did it with an 8-meter ground telescope and a tool specifically designed and developed to detect these types of planets in the Alpha Centauri system.
The authors are confident that NEAR can perform well, even compared to much larger telescopes. The conclusion of the paper contains a description of the overall sensitivity of the instrument. Then they write: “It would in principle be sufficient to locate an Earth-analogous planet around α Centauri A (~ 20 µYou) within a few hours, which is in line with expectations for the ELTs.”
The E-ELT has a primary mirror of 39 meters. One of its capabilities and design objectives is to directly depict exoplanets, especially smaller, Earth-sized ones.
Of course, the E-ELT will be an extremely powerful telescope that will undoubtedly stimulate scientific discovery for a long time, not only in exoplanet imaging, but also in various ways.
And other giant ground telescopes will also change the imagery of the exoplanet.
What took hours before seeing NEAR, the E-ELT, the Thirty Meter Telescope or the Giant Magellan Telescope can only take a few minutes.
NEAR can not compete with the telescopes, and it was never intended.
But if these results are confirmed, NEAR has succeeded where no one else has, and for a fraction of the price of a new telescope.
Either way, what NEAR has achieved probably represents the future of exoplanet research. Instead of broad surveys like Kepler and TESS, scientists will soon be able to focus on individual planets.
This article was originally published by Universe Today. Read the original article.