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Exoplanets are cunning little beasts.
Because they are so small, so dim, so far away, it is very challenging and rare to see them directly. Similarly, we usually infer their existence from the effects of their host stars – i.e. in the odd case, when we see something directly, it is a cause for excitement.
Finding an exoplanet called COCONUTS-2b and orbiting a star called COCONUTS-2 is all you need to feel the excitement.
Not only COCONUTS-2b (named for the Cool Companions in the Ultrawite Orbit Survey) but also the closest aircraft ever shot directly to Earth – just 35 light-years away – is rare in Exoplanet discoveries: the relatively cold, massive galaxy at a distance of about its orbit.
“With a gigantic planet in a super-white-split orbit, and a very cold central star, COCONUTS-2 represents a very different planetary system than our own solar system.” Astronomer Jojian Zhang said University of Hawaii Institute of Astronomy.
COCONUTS-2b, red dot on top left. (Letters from Zhang et al., The Astronomy Journal, 2021)
The most common methods for locating an exoplanet depend on two effects that exoplanets may have on a host star. The first is called the mode of transport, and it relies on changes in the depth of light of a star. When an orbit passes in its orbit between us and its host star, this transport is detected as faint swells in the star’s light.
The radial velocity (or ‘oscillation’) method depends on changes in the wavelength of light of a star. As the Exoplanet orbits the star, it exerts a small gravitational influence, causing the star to move brilliantly. When it moves in a small circular motion, the wavelength of its light changes slightly as it moves towards us.
Both of these methods are very large, and close to the planet – it is best to detect the largest because the signal is large and easy to detect, and they will close as they rotate quickly, meaning astronomers will be able to receive as many signals as they need to ensure that they are generated by an orbital body. Is not a passing object.
However, the larger distance from its host star – about 6,471 astronomical units, which is 6,471 times the average distance between the Earth and the Sun – made COCONUTS-2b visible in live images. At that distance, its orbital period is about 1.1 million years (which is There may be a record For known exoplanet).
“It is usually very difficult to directly detect and study light coming from the gas-giant planets around other stars, because the planets we see usually have small-separation orbits, so that their host star’s glare.” Said astronomer Michael Liu University of Hawaii.
Although it is cooler than a gas giant exoplanet, it is still beautiful, with a temperature of about 434 Kelvin (161 degrees Celsius, or 322 degrees Fahrenheit), despite its distance from the star’s heat.
COCONUTS-2b is still young, up to about 800 million years old; Its warmest temperature is the residual heat from the formation of the Exoplanet, which is trapped inside the vast Exoplanet and is six times the mass of Jupiter. This heat causes the exoplanet to glow dimly in the infrared wavelengths – sufficient to see clearly in direct images.
Its enormous orbital distance will have other benefits for future research. This may help us to better understand how gas giants are formed, which we do not yet understand well – and staring at it will help us to better understand the diversity of gas giants.
“With its large orbital separation, COCONUTS-2b would be an excellent laboratory for studying the atmosphere and composition of a young gas-giant planet.” Liu said.
Research has been published Letters from the Journal of Astronomy.
