Meet Ross 508b: Scientists discover a “SUPER EARTH” exoplanet four times the size of our own planet orbiting a star 36.5 light-years away
- New “super-Earth” that is four times larger than our own planet has been discovered
- The exoplanet, named Ross 508b, orbits a star 36.5 light-years away.
- Previous research suggests that the world is likely to be rocky rather than gaseous
- “Super-Earths” are more massive than Earth but do not exceed the mass of Neptune
A new “super-Earth” four times the size of our own planet has been seen orbiting a star just 36.5 light-years away.
The exoplanetnamed Ross 508b, was discovered in the so-called habitable zone by a faint red dwarf that it circles every 10.75th day.
It is much faster than the Earth’s orbit in 365 days, but the star that the Ross 508b orbits is much smaller and weaker than our sun.
Although they are in this “Goldilocks” zone – where it is not too hot and not too cold for liquid water to exist – experts believe that it is unlikely to be habitable for life as we know it.
But based on what is known about planetary mass boundaries, the newly identified world is likely to be terrestrial, or rocky, in the same way as the earth, rather than gaseous.
A new “super-Earth” four times the size of our own planet has been seen orbiting a star just 36.5 light-years away. The exoplanet Ross 508b was discovered in the habitable zone by a faint red dwarf. Pictured is an artist’s impression of a super-earth orbiting a red dwarf
Ross 508b was seen by an international team of astronomers using the National Astronomical Observatory of Japan’s Subaru telescope in Hawaii.
It has been described in a magazine led by astronomer Hiroki Harakawa, from the Subaru Telescope, and is the campaign’s first exoplanet.
Ross 508b orbits a nearby M dwarf star known as Ross 508, hence its name.
‘Super Earths’ are planets that are more massive than ours but that do not exceed Neptune’s mass.
Although the term only refers to the mass of the planet, it is also used by experts to describe planets larger than Earth but smaller than the so-called “mini-Neptunes”.
“We showed that the 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 equivalent in photometry or star activity indicators, but is well adapted to a Kepler orbit due to a new planet, Ross 508b.”
Ross 508, with 18 percent of our Sun’s mass, is one of the smallest, faintest stars in an orbiting world that has been discovered using radial velocity.
The main technology for finding exoplanets is the transit method, which is what NASA’s exoplanet hunting telescope TESS uses, and Kepler before that.
Ross 508b was seen by an international team of astronomers using the National Astronomical Observatory of Japan’s Subaru telescope in Hawaii. They found it with a technology known as radial velocity
This means that an instrument stares at the stars and searches for regular dips in their light caused by an object orbiting the earth and the star.
Astronomers then use the transit depth to calculate the object’s mass, with the larger the light curve the larger the planet.
A total of 3,858 exoplanets have been confirmed using this method.
But the other technique is the radial velocity, which is also known as the wobble or Doppler method.
It can detect “wobbles” in a star caused by the gravitational force of an orbiting planet.
The wobblers also affect the light coming from the star. As it moves toward the earth, its light seems to shift toward the blue part of the spectrum, and as it moves away, it appears to shift toward the red.
The new discovery suggests that future studies of radial velocities in infrared wavelengths have the potential to reveal a large number of exoplanets orbiting dark stars.
“Our discovery shows that the near-infrared RV search can play a crucial role in finding a low-mass planet around cool M-dwarfs like the Ross 508,” the researchers wrote in their paper.
The research has been published in the Publications of the Astronomical Society of Japan and is available at arXiv.
Scientists study the atmosphere of distant exoplanets using huge space satellites such as Hubble
Distant stars and their orbiting planets often have conditions that are unlike anything we see in our atmosphere.
To understand these new worlds, and what they are made of, scientists must be able to discover what their atmospheres consist of.
They often do this by using a telescope similar to NASA’s Hubble telescope.
These huge satellites scan the sky and lock themselves on exoplanets that Nasa thinks may be of interest.
Here, the sensors on board perform various forms of analysis.
One of the most important and useful is called absorption spectroscopy.
This form of analysis measures the light that comes out of a planet’s atmosphere.
Each gas absorbs a slightly different wavelength of light, and when this happens, a black line appears on a complete spectrum.
These lines correspond to a very specific molecule, which indicates its presence on the planet.
They are often called Fraunhofer lines after the German astronomer and physicist who first discovered them in 1814.
By combining the different wavelengths of light, scientists can determine all the chemicals that make up the atmosphere on a planet.
The key is that what is missing provides clues to find out what is available.
It is very important that this is done with a space telescope, as the Earth’s atmosphere would then interfere.
Absorption from chemicals in our atmosphere would skew the sample, so it is important to study the light before it has had a chance to reach the earth.
This is often used to look for helium, sodium and even oxygen in foreign atmospheres.
This graph shows how light passing from a star and through the atmosphere on an exoplanet produces Fraunhofer lines indicating the presence of key compounds such as sodium or helium.
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