When a star nears death from lack of fuel, he begins to suddenly increase his volume. It does so in a process where it can gobble up just about anything around it. For example, when our Sun reaches its decline, it will take the innermost planets of the Earth with it. Solar system, including Earth. This is something that has been studied for a long time. However, until now no one had managed to capture the exact moment in which a star engulfs a nearby planet.
The moment before and after has been observed, but not just when one star swallows the other. For this reason, the finding that he has just published in Nature a team of astronomers from MIT and other research centers is especially interesting.
And it is that, for the first time in history, they have captured red-handed to a star while swallowing a planet. It has taken more than a year and the observation with different instruments to be able to affirm it with enough certainty. But, without a doubt, the wait has been worth it, because these scientists have made history.
the phases of a star
A star is born when the accumulation of dust and gas rich in helium and hydrogen of one nebula it condenses and collapses. At this stage we are facing a protostar, which gradually heats up, until it reaches a suitable temperature to carry out nuclear fusion, using hydrogen as fuel. That nuclear fusion can cause the expansion of the star. However, this is so massive that its own gravity compensates for this effect.
But this cannot happen forever. There comes a point where the fuel starts to wear out, so it loses mass and gravity is not enough to keep it from expanding. There is less and less fuel and the star is more swollen, reaching an end that will depend on its mass. If it is a medium-sized star, when there is no fuel left, its stars separate. outermost layersleaving only its nucleus, which we know as White dwarf. On the other hand, if it is much more massive, when its fuel is spent it gives rise to an explosion, known as supernova and then to a neutron star. And finally, if it is one of the most massive stars, it also explodes, but it generates a black hole.
The hunt red-handed of a planet
This story begins in 2020, when Kishalay Fromfrom MIT, was analyzing data taken by the Zwicky Transitional Facility (ZTF), executed at Caltech’s Palomar Observatory in California. ZTF’s goal is to scan the sky for stars that quickly change brightness. Thus, it is possible to detect, for example, the aforementioned supernovae, or also gamma ray bursts.
Despite being familiar with these brightness changes, one night the astronomer observed something he had never seen before. A star brightened by a factor of 100 in just one week. It was something totally unusual, so he asked for the collaboration of the telescopes of the Keck Observatory, from Hawaii. These are equipped with spectrographs, which can help determine a star’s composition. Thus, he hoped to confirm that it was a binary star. That is, a pair of stars, in which one steals matter from the other, releasing a lot of energy. The problem is that these stars typically emit hydrogen and helium. But none of these gases were found. Basically, what they observed in Hawaii was a series of peculiar compounds that are only found in cool stars. But how can it be?
If the star were getting excited enough to shine that way, it should be warming up, not cooling down. It took a year to find the missing piece of the puzzle.
De and other scientists who had been involved later decided to resort to a infrared camera, located at the Palomar observatory. They thought this would be useful, since measurements in the infrared make it possible to detect signals from much colder material.
And sure enough, the source was very bright in the near infrared. That star was very cold. It could be a star that was merging with another, instead of causing an outburst. But to be sure, they turned to NASA’s infrared space telescope, NEOWISE. This allowed them to verify that the amount of energy released was 1/1000 times that of any star fusion. This indicated that, if a merger had occurred, the second member of the pair was not another star, but something smaller. Given the Jupiter it has a mass just 1000 times smaller than that of the Sun, it seemed to fit that it was a planet of this size.
Therefore, the flash did not come from the star, but from the planet succumbing before being swallowed by the dying star. This, since it was spending its fuel, was getting colder, hence the materials detected in Hawaii.
This time they have managed to observe the hunt at the exact moment. Not before, not after. This is basically what will happen to the Earth with the Sun, but there is still a long way to go. 5 billion yearsso calm down. For now, all that remains is to celebrate this discovery. It has been a complicated puzzle, but putting all the pieces together has been very exciting.