It is possible that astronomers using a new technique have not only found a super-Earth in a neighboring star, but have also been able to do so directly. And it could be nice and cozy in the living area around Alpha Centauri.
It is much easier to see giant planets than Earth-sized planets. Regardless of the detection method used, larger planets are simply a larger needle in the cosmic haystack. But in general, astronomers are very interested in Earth-like planets. And finding them is much harder.
We thought we would have to wait for the ultra-powerful telescopes that are currently being built before we could directly imagine the exoplanets.
Facilities such as the Giant Magellanic Telescope and the Extremely Large European Telescope will bring enormous observational power to the task of exoplanet imaging.
But a team of researchers has developed a new technique that could do the job. They say they have imagined a possible sub-Neptune / super-terrestrial-sized planet orbiting one of our closest neighbors, Alpha Centauri A.
The team presented their observations in an article a Communications on Nature entitled “Image of low-mass planets within the habitable zone of α Centauri”. The lead author is Kevin Wagner, astronomer and Sagan member at the University of Arizona.
Although astronomers have previously found low-mass exoplanets, they have never felt their light. They have seen the planets reveal themselves by pulling on their stars. And they have seen how the light from the stars that house these planets falls when the planet passes in front of the star.
But they have never imagined it directly. So far, maybe.
This new method of detection reaches the infrared. One of the challenges of the Earth-sized infrared image of exoplanets is to discern the light that comes from an exoplanet when that light is dragged by all the background infrared radiation from the star.
Astronomers can look for exoplanets at wavelengths where the infrared bottom is reduced, but at these same wavelengths Earth-like temperate planets are weak.
One method is to look at the near infrared (NIR) part of the spectrum. At NIR, the planet’s thermal glow is not so swept away by the star. But starlight is still blinding and millions of times brighter than the planet. Therefore, just looking at the NIR is not a total solution.
The solution may be the NEAR (New Earths in the AlphaCen Region) instrument used in this research. NEAR is mounted on the very large telescope (VLT) of the ESO (European Southern Observatory), in Chile. It works with the VISIR instrument, also in the VLT. The group behind NEAR is the Breakthrough Watch, which is part of Yuri Milner’s Breakthrough Initiatives.
The NEAR instrument not only observes the desirable part of the infrared spectrum, but also uses a coronograph.
The Breakthrough group thought that the NEAR instrument used in an 8-meter terrestrial telescope would allow better observation of the Alpha Centauri system and its planets.
So, they built the instrument in collaboration with ESO and installed it in the Very Large Telescope.
This new finding emerged as a result of 100 hours of accumulated observations with NEAR and the VLT.
“These results,” the authors write, “demonstrate the viability of images of rocky exoplanets of habitable areas with current and future telescopes.”
Running 100 hours of commissioning was to demonstrate the power of the instrument.
The team says that, based on approximately 80 percent of the best images in this race, the NEAR instrument is an order of magnitude better than other methods for observing “… warm subneptune-sized planets in much of the living area of α Centauri. “
Possibly, they also found a planet. “We are also talking about a possible detection of exoplanet or exozodiacal disk around? Centauri A,” they write. “However, an instrumental artifact of unknown origin cannot be ruled out.”
This is not the first time astronomers have found exoplanets in the Alpha Centauri system.
There are a couple of confirmed planets in the system and there are other candidates as well.
But none of them have been directly imagined as this potential new planet, which is named the C1 placeholder, and is the first potential detection around the system’s M dwarf, Proxima Centauri.
Follow-up observations must confirm or cancel the discovery.
It’s exciting to think that an exoplanet of the warm Neptune class could be orbiting a Sun-like star from our nearest neighboring star system. One of the goals of the innovative initiatives is to send light sailing spacecraft to the Alpha Centauri system and give us a closer look.
But that perspective is not available at this time. And, in a way, this discovery is not so much about the planet, but about the technology developed to detect it.
The vast majority of exoplanets discovered are giant planets similar in mass to Jupiter, Saturn and Neptune. They are the easiest to find. But as humans on Earth, we are primarily interested in planets like ours.
Earth-like planets in the habitable zone of a star excite us with the prospects of life on another planet. But they can also tell us a lot about our own solar system and how solar systems form and evolve in general.
If C1 turns out to be a planet, the Breakthrough group has been successful in a vital effort. They are the first to detect an Earth-like planet using direct images.
Not only that, but they did it with an 8-meter terrestrial telescope and an instrument designed and developed specifically to detect such planets in the Alpha Centauri system.
The authors are confident that NEAR can work well, even compared to much larger telescopes. The conclusion of the article contains a description of the general sensitivity of the instrument. They then write that “This in principle would be enough to detect an analog planet Earth around α Centauri A (~ 20 µJy) in a few hours, which is consistent with the expectations of ELTs.”
The E-ELT will have a 39-meter primary mirror. One of its design capabilities and goals is to directly imagine exoplanets, especially the smallest Earth-sized ones.
Of course, the E-ELT will be an enormously powerful telescope that will undoubtedly fuel scientific discovery for a long time, not just in exoplanet images but in other forms.
And other giant terrestrial telescopes will also change the image set of exoplanets.
What took hours to see on PROP may take just a few minutes to see on the E-ELT, the Thirty Meters Telescope, or the Magellanic Giant Telescope.
NEAR cannot compete with these telescopes and never was.
But if these results are confirmed, then NEAR has succeeded where no one has, and for a fraction of the price of a new telescope.
Either way, what NEAR has achieved probably represents the future of research on exoplanets. Instead of powerful 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.