400 light-years away, a tiny exoplanet is making its way into the universe.
This, in and of itself, is not surprising. Science has discovered thousands of exoplanets, that is, planets outside the solar system, and it assumes that all of them too must have been newborns at some point. What makes this exoplanet special is that astronomers have obtained a direct image of it, an almost impossible feat.
It’s called 2M0437b and is one of the smallest exoplanets ever directly imaged. This could give us a new window into the planet formation process, which in turn could help us understand how the solar system originated and evolved.
“This serendipitous discovery adds to the elite list of planets that we can observe directly with our telescopes,” said astronomer Eric Gidus of the University of Hawaii at Manoa.
“By analyzing the light from this planet we can tell something about its composition, and possibly where and how it formed in the long disk of gas and dust around its host star.”added.
There are some excellent reasons why it is possible to image exoplanets directly. Compared to the stars orbiting them, the exoplanets are very small and faint, Which means they are often too faint to be seen with current telescope technology.
Instead, exoplanets are generally discovered based on the two effects they have on their host stars.. If an exoplanet passes between Earth and the star on its orbital path, small periodic changes in the star’s light can be detected.
Furthermore, an exoplanet would exert a slight gravitational effect on the star (since the bodies orbit a common center), causing the star to “move” a little bit into place, causing the wavelength of its light to change slightly.
These signals are easy to detect when the planet is very massive and very close to the star, which is why most confirmed exoplanets are massive and in close orbits. But it’s hard to directly visualize exoplanets in very close orbits, because they tend to be heavily overwhelmed by their host stars.
Exoplanet 2M0437b is very large, but it is also very far from its host star, 2M0437, about 100 AU. (Pluto is about 40 AU from the Sun.) Exoplanets that are too far from their star are usually too cold to emit infrared radiation, but this is where the youngsters of 2M0437b play an important role.
Since its age is only a few million years, the baby planet outside the solar system is still relatively hot due to intense planet formation processes, About 1400 to 1500 K (1127 to 1227 °C, or 2060 to 2240 °F). This means that it glows poorly in infrared radiation, It is enough to see it from a distance of 417 light years.
It was discovered in 2018 using the Subaru Telescope in Hawaii, and follow-up near-infrared observations were made with the WM Keck Observatory. For three years, the research team tracked the star as it moved across the sky and was able to confirm that 2M0437b was moving with it.
“The wonderful data from the Keck Observatory allowed us to confirm that the faint neighbor is moving in space with its star and is therefore a true companion.” said astronomer Adam Krause of the University of Texas at Austin.
“Eventually, we can even measure its orbital motion around the star,” added.
The team believes that the new system would be an excellent candidate for following up on observations with the Hubble Space Telescope. So far, the star and its extrasolar planet have been observed using ground-based observatories, which should correct the effect of the twisting of the Earth’s atmosphere on starlight. Hubble does not have this problem.
These observations should be able to help constrain the star’s properties. We don’t know exactly how old it is or its mass. They can even detect chemical signals in 2M0437b’s atmosphere, which in turn could reveal more information about how it formed.
“We are all waiting for more similar discoveries and more studies of this type of planet thanks to the technologies of future telescopes,” said astronomer Michael Liu of the University of Hawaii.