the james webb space telescope continues to prepare his instruments to begin what should be a long and fruitful season of work. However, its predecessor kept giving us good news. And it’s thanks to Hubble a team of scientists from Johns Hopkins University succeeded in detecting a star which formed 900 million years after the Big Bang. This makes it the most distant ever found, as finding star systems older than 1,000 million years after the big bang was a challenge.
In fact, in the history of the universe, there is a vacuum of immense uncertainty, between 400,000 years and 1,000 million years after the Big Bang. The detection limit of the most precise man-made instruments has kept scientists from laying eyes on this period of history. However, Hubble is not just any instrument.
Thanks to him, a galaxy was formed 250 million years after the Big Bang. But nothing like it had been done with a star or star system. At least, it hadn’t been done until now, since it was Hubble itself that once again did it. The research data is published today in Nature.
The Dark Ages after the Big Bang
radiation from microwave background It is a type of electromagnetic radiation that occupies the entire universe. Thanks to their study, we know with some precision what the universe looked like. 400,000 years after the Big Bang.
At that time, the temperature was low enough for protons and electrons to come together to give neutral hydrogen. In this way, part of the seed was sown that would eventually give birth to stars. However, it was still early.
The period between 400,000 years and 1 billion years after the Big Bang is known as the dark age of the universe.
The problem is that from this moment there is a long period during which it is not known how everything has evolved. The following data, which had been obtained until recently, came from 1 billion years after the Big Bang. At that time, there were already small galaxies, gamma-ray bursts, and even bright quasars likely powered by supermassive black holes as heavy as a billion suns. Gradually, all sorts of objects that have appeared since have been detected. But at first it was all doubt.
According to the physicist Tom Abel in an article for physics todaythis period is known in cosmology as the dark period and contains many questions. For example, which formed first, black holes or galaxies? The most massive stars or those of low mass? Could some of these early stars still exist today? These are all unknowns that could only be solved by an instrument as powerful as the The Hubble Space Telescope.
It was he who discovered that the galaxy was formed 250 million years after the Big Bang, the MACS1149-JD1. And it is now he who found the first known star of the dark period of the universe. Thanks to him, we have a lot of data on this star, which they named Eendel, which means “morning star” in Old English. There are still a few unknowns. However, it is expected that James Webb will be ready and that, as a worthy successor, he can provide the information that we lack. But what do we know so far about this star?
Another great find from Hubble
Hubble was able to detect this star thanks to an effect known as gravitational lens. This occurs when light from very distant objects bends when it encounters a very massive object located between its source and the observer.
By observing this effect, patterns can be created about where this light is coming from. In this case, according to the study which has just been published in Natureall models pointed out that its radius is less than that of any star cluster. Therefore, they were not in front of a set of stars, but in front nail or at most one binary star system.
The mass of the star is probably more than 50 times that of our Sun.
They were also able to calculate that its mass may be greater than 50 times that of the Sun and he has a redshift 6.2. This term refers to a phenomenon that occurs when electromagnetic radiation emitted or reflected by an object, usually visible light, appears red-shifted, located at the extreme end of the electromagnetic spectrum. These are data that can be used to calculate the distance of an astronomical object. The higher the number, the further away it will be. Or, which comes to the same thing, the oldest will be its origin in the history of the universe.
Previous observations of stars detected and magnified by gravitational lensing have yielded redshift values of between 1 and 1.5. It is much larger, as it is the most distant single star ever detected. So much so that it formed 900 million years after the Big Bang.
With the Models made from hubble data These scientists also concluded that it was most likely at a temperature of 20,000K However, they were unable to accurately determine its spectral type. But there are still ways to find out. And it is that, when ready, the space telescope James Webb It could give this data and, in addition, report its mass and temperature more accurately than Hubble.
Veteran and rookie will work as a team to shed light on the darkest period in the history of the universe.
