A new “super-Earth” four times larger than our planet has been seen orbiting a star just 36.5 light-years away.
The exoplanet, named Ross 508 b, was discovered in the so-called habitable zone of a faint red dwarf that orbits every 10.75 days.
That’s much faster than Earth’s 365-day orbit, but the star Ross 508b orbits is much smaller and lighter than our sun.
Despite being in this “temperate” zone – where it’s neither too hot nor too cold for liquid water – experts think it’s not likely to be habitable as we know it.
But based on what is known about the limits of planetary mass, it is likely that the New World will be terrestrial, or rocky, just like Earth, rather than gaseous.
A new “super-Earth” four times larger than our planet has been seen orbiting a star just 36.5 light-years away. Exoplanet Ross 508b has been discovered in the habitable zone of a faint red dwarf. In the image, an artist’s impression of a giant Earth orbiting a red dwarf
An international team of astronomers discovered ROS 508b using the National Astronomical Observatory of Japan’s Subaru Telescope in Hawaii.
Described in a paper led by astronomer Hiroki Harakawa, of the Subaru Telescope, it is the campaign’s first exoplanet.
Ross 508b orbits a nearby M-dwarf star known as Ross 508, which is why it was given its name.
“Super planets” are planets larger than our planets, but they do not exceed the mass of Neptune.
Although the term refers only to the mass of the planet, it is also used by experts to describe planets larger than Earth but smaller than the so-called “miniature Neptune”.
“We show that M4.5 dwarf Ross 508 has a significant RV periodicity at 10.75 days with possible aliases at 1,099 and 0.913 days,” the researchers said.
“This periodicity has no analogues in photometry or indices of stellar activity, but it is well suited by Kepler’s orbit because of a new planet, Ross 508 b.”
Ross 508, at 18 percent the mass of our sun, is one of the smallest and lightest stars with an orbiting world detected using radial velocity.
The main technique for finding exoplanets is the transit method, which is what NASA’s TESS telescope uses to hunt exoplanets, as well as Kepler before it.
An international team of astronomers discovered ROS 508b using the National Astronomical Observatory of Japan’s Subaru Telescope in Hawaii. They found it using the well-known radial velocity technique
It involves an instrument gazing at the stars and looking for regular dips in its light caused by an object orbiting the Earth and the star.
Astronomers then use the depth of transit to calculate the mass of the object, the larger the curve of light, the larger the planet.
A total of 3,858 exoplanets have been confirmed with the help of this method.
But the other technique is radial velocity, which is also known as doppler or doppler method.
It can detect “oscillations” in a star caused by the gravitational force of an orbiting planet.
The vibrations also affect the light coming from the star. When it moves toward Earth, its light appears to shift toward the blue part of the spectrum, and when it moves away, it appears to be moving toward red.
The new discovery suggests that future radial velocity scans at infrared wavelengths have the potential to detect a large number of exoplanets orbiting dim stars.
“Our discovery demonstrates that a near-infrared search of the RV could play a critical role in finding a low-mass planet around cold M dwarfs like Ross 508,” the researchers wrote in their paper.
The research has been published in Publications of the Japanese Astronomical Society, and is available on arXiv.
Scientists study the atmosphere of distant exoplanets using huge satellites in space such as Hubble
Distant stars and the planets that orbit them often have conditions unlike anything we see in our atmosphere.
To understand this new world and its components, scientists need to be able to discover what the atmospheres are made of.
They often do this with a telescope similar to NASA’s Hubble Telescope.
These massive satellites are scanning the sky and pinning them to exoplanets that NASA thinks might be of interest.
Here, the onboard sensors perform various forms of analysis.
Of the most important and useful is absorption spectroscopy.
This form of analysis measures the light emitted by the planet’s atmosphere.
Each gas absorbs a slightly different wavelength of light, and when this happens a black line appears over the entire spectrum.
These lines correspond to a very specific molecule, indicating its presence on the planet.
They are often called the Fraunhofer lines after the German astronomer and physicist who first discovered them in 1814.
By combining all of the different wavelengths of lights, scientists can determine all of the chemicals that make up a planet’s atmosphere.
The key is that what is missing, provides the clues to know what is there.
It is very important that this is done by space telescopes, as they will enter the Earth’s atmosphere.
Absorption from chemicals in our atmosphere can deflect the sample, which is why it’s important to study the light before it has a chance to reach Earth.
This is often used to search for helium, sodium, and even oxygen in exotic atmospheres.
This graph shows how light passing from a star and through the atmosphere of an exoplanet produces Fraunhofer lines that indicate the presence of major compounds such as sodium or helium.