Meet Ross 508b: Scientists discover a ‘SUPER EARTH’ exoplanet four times larger than our own planet orbiting a star 36.5 light years away
- A new “super Earth” four times larger than our own planet has been spotted
- The exoplanet, named Ross 508b, orbits a star 36.5 light years away.
- Previous research suggests the world is likely to be rocky rather than gassy
- The “super-Earths” are more massive than the Earth but do not exceed the mass of Neptune
A new “super Earth” four times larger than our own planet has been spotted orbiting a star just 36.5 light years away.
The exoplanet, which has been dubbed Ross 508b, was discovered in the so-called habitable zone of a pale red dwarf that it rotates every 10.75 days.
That’s much faster than Earth’s 365-day orbit, but the star around Ross 508b is much smaller and fainter than our sun.
Although it is in this “Goldilocks” zone – where it is neither too hot nor too cold for liquid water to exist – experts believe it is unlikely to be habitable for life as it is. we know her.
But based on what is known of planetary mass limits, the newly identified world is likely to be terrestrial, or rocky, similar to Earth, rather than gaseous.
A new “super Earth” four times larger than our own planet has been spotted orbiting a star just 36.5 light years away. Exoplanet Ross 508b was discovered in the habitable zone of a pale red dwarf. Pictured is an artist’s impression of a super Earth orbiting a red dwarf
Ross 508b was spotted by an international team of astronomers using the Subaru Telescope at the National Astronomical Observatory of Japan in Hawaii.
It was described in a paper led by astronomer Hiroki Harakawa, of 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.
The “Super-Earths” are planets more massive than ours but which 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 “mini-Neptunes”.
“We showed that the M4.5 Ross 508 dwarf 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 stellar activity indicators, but is well suited to a Keplerian orbit due to a new planet, Ross 508b.”
Ross 508, at 18% the mass of our sun, is one of the smallest and faintest stars with an orbiting world that was discovered using radial velocity.
The main technique for finding exoplanets is the transit method, which is the one used by NASA’s TESS exoplanet-hunting telescope, as well as Kepler before it.
Ross 508b was spotted by an international team of astronomers using the Subaru Telescope at the National Astronomical Observatory of Japan in Hawaii. They found it with a technique known in radial velocity
It is an instrument that fixes stars and looks for regular dips in their light caused by an object orbiting between the Earth and the star.
Astronomers then use the depth of the transit to calculate the object’s mass, with the longer the light curve, the larger the planet.
A total of 3,858 exoplanets have been confirmed using this method.
But the other technique is that of the radial velocity, also known as the oscillation method or the Doppler method.
It can detect the “wobbles” of a star caused by the gravitational pull of an orbiting planet.
The oscillations also affect the light coming from the star. As it moves towards Earth, its light appears shifted to the blue part of the spectrum, and as it moves away, it appears red-shifted.
The new discovery suggests that future radial velocity surveys in infrared wavelengths have the potential to uncover large numbers of exoplanets orbiting dim stars.
“Our discovery demonstrates that near-infrared RV search can play a crucial role in finding a low-mass planet around cold M dwarfs like Ross 508,” the researchers write in their paper.
The research has been published in the Publications of the Astronomical Society of Japan and is available on arXiv.
Scientists study the atmosphere of distant exoplanets using huge space satellites like Hubble
Distant stars and their orbiting planets often have conditions unlike anything we see in our atmosphere.
To understand these new worlds and what they are made of, scientists must be able to detect the composition of their atmospheres.
They often do this using a telescope similar to NASA’s Hubble Telescope.
These huge satellites scan the skies and fixate on exoplanets that NASA says might be of interest.
Here, on-board sensors perform different 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 across a full spectrum.
These lines correspond to a 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 all the different wavelengths of light, 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 discover what is present.
It is vitally important that this be done by space telescopes, as the Earth’s atmosphere would then interfere.
Absorbing chemicals into our atmosphere would skew the sample, which is why it’s important to study the light before it has had a chance to reach Earth.
This is often used to search for helium, sodium, and even oxygen in extraterrestrial atmospheres.
This diagram shows how light passing from a star and through an exoplanet’s atmosphere produces Fraunhofer lines indicating the presence of key compounds such as sodium or helium