Bad astronomy | The theoretical exoplanet AB Aurigae b can be seen directly in the photos

With more than 5,000 exoplanets, we now know that the worlds orbit other stars. Most of them were discovered by the mode of transport, where the planet causes a small eclipse and slightly blocks the light of its host star. This is an indirect method; We do not see the planet, it’s the impact it has on the light of its star.

So far, less than 60 orbits have been captured directly; That is, as seen in the actual pictures taken under their star. This method works best in infrared light with young stars – newly formed planets glow in IR due to their own heat, while stars do not emit much infrared, making it easier to spot planets. It also works best for planets that are 50-300 times farther from the Sun than Earth – farther from the star.

This will work even for younger planets. Very young, They are still evolving.

AB Aurigae is a young star, 2-4 million years old and 560 light-years from Earth. It is larger, hotter, and brighter than the sun, which we call a Front primary row starDoes not yet combine hydrogen and helium at its core, but is very close.

It is surrounded by formed dust and gas. At a distance of about 18 billion kilometers from the star there is a dust ring found by ALMA at a millimeter wavelength, and a flat gas disk is inside. The gas disk has spiral arms, which theoretical models represent a planet or brown. Dwarf – an object with mass between a planet and a star – where its gravitational pull disturbs the gas. The dust ring is abruptly cut off at its inner edge; Another indicator of a decent massive body orbiting the star, whose gravity breaks the inner ring.

With this in mind, a team of astronomers used Hawaii’s Large Subaru Telescope and the Hubble Space Telescope to search for any possible planets known as protoplanets orbiting AB Aurigae.

Looks like they found one.

A bright point is found at a slight distance from the star, approximately 90 times the distance of the Earth-Sun or about 14 billion kilometers – slightly more than twice that of Pluto from the Sun. It is outside the main disk of gas but inside the dust ring.

AB Aur moves slowly compared to more distant objects in our sky, and if this point were a background star or galaxy it would be in a very different position in pictures 15 years later. This was seen in Hubble’s infrared observations in 2007, and is almost the same as the star in the new observations. It is also seen in pictures taken with the Subaru telescope, so it is not due to some telescope or processing artifact. It’s real, it moves with the star.

Not only that, you can see the spot moves a little bit over time between pictures Around The star corresponded to orbiting the star in the opposite direction at that distance. This is true for a protoplanet and some large gases, so this is interesting but not conclusive.

At best, though: its position matches the theoretical predictions of where a large protoplanet should be to illustrate the vortex features on the gas disk, which is exciting.

This is clearly not a point proof, not a simple point, in the pictures. Its size is a maximum of about 2 billion kilometers across, which is enormous. However, if a still-forming planet were at that distance from its star and about 4 times the mass of Jupiter, it would be a disk orbiting an object of that size. So again, this is consistent with a massive protoplanet.

If it were a bubble of dust orbiting the star, the light we see from it would be very polarized; That is, the waves of light are strongly aligned. This No. Seen, light comes from matter itself and not only from reflected light. In other words, it glows. It is also found in the form of light emitted by the energetic hydrogen gas, which is expected to fall on a planet surrounded by gas.

Spot colors correspond to the fact that it is a large but still very warm planet. Using theoretical models, astronomers were more suited to Jupiter’s mass 9 times, 2.75 times its diameter – it is very large, but it has not yet formed and settled – and with a temperature of about 2,000. C. It is very hot, but it is expected again. One part in a million of Jupiter’s mass each year – how quickly matter falls on it – is matched by the accumulation rate. It may not seem big, but Jupiter is a beast. That accumulation rate is equal to 5,000 trillion tons a day.

That is, 66 billion tons per second. Per Second. It’s like a 4 – kilometer wide asteroid – half the diameter of a dinosaur killer – affecting the protoplanet for hundreds of thousands of years, every day, every second of every day. No wonder it glows hot.

Having said all this, this is not really conclusive evidence of being a protoplanet, but it is very conclusive evidence.

It makes me so happy. As I wrote earlier, this was the day I worked on the star’s 1999 Hubble Observations. This potential protoplanet was very close to the star to see in our data, but new observations were made in a different way, which allowed the planet to be teased from all the light of the star. Impressive.

It is so close to us! We see stars forming all over the Milky Way, all the time, and this is just another part of the galaxy that shows that the planets are forming along with them. The universe is full of planets, innumerable worlds, and we begin to discover them.


The tip of the ice shield for him for alerting me to the work of Thein Curie, the primary author of this research.

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