US, WASHINGTON (ORDO NEWS) — Astronomers cannot understand how much the North Star weighs and how old it is. One of the most remarkable luminaries in the earth’s sky seems to be playing with humanity: the more we learn about it, the less we understand.
This is the conclusion made in the preprint of the scientific article published on arXiv.org.
The North Star has been pointing the way north for humanity for millennia. But it is noteworthy not only this.
The fact that the naked eye is seen as a single star, is a system of three stars. Polar A is a supergiant with luminosity of almost one and a half thousand suns. She has a rather distant companion, Polar B, and a tiny close companion, Polar Ab.
Polar A is the Cepheid closest to us. This is a special class of pulsating luminaries, which are characterized by a clear relationship between the period of pulsations and luminosity. By calculating the latter and comparing it with the apparent brilliance of the star, you can find out the distance to the star. Since Cepheids are visible at great distances even by cosmic standards, they serve as one of the “measuring lines” with which astronomers measure the universe .
Meanwhile, the Cepheid closest to Earth remains a mystery to scientists. The authors of the new article brought together the results of numerous observations and computer simulations in the hope of resolving the contradictions, but this could not be done.
It is curious that both of the questions that astronomers cause the greatest difficulties were those that were indecent to ask a lady: how much she weighs and how old she is. But astronomers, alas, are not gallant and want to know absolutely everything.
Beauty on the scales
The first difficulty concerns the mass of the star. One way to calculate it is to use seemingly well-tested models of the structure of Cepheids. These calculations show that Polar A is about seven times heavier than the sun.
On the other hand, at the services of astronomers, her companion is Polar B. He makes a complete revolution around his partner in about 26 earth years. Having determined the parameters of its orbit, we can calculate the mass of Polar A. The trouble is that a completely different value is obtained: 3.45 0.75 solar masses. And scientists do not yet know how to resolve this contradiction.
A woman is as old as she looks?
Another mystery is related to the age of Polar A and Polar B. The age of a star can be found on the basis of its spectrum, luminosity, and generally accepted theoretical models. And it turns out that Polar B is much older than her more massive “girlfriend.”
It is very strange. Stars form a binary system precisely because they are formed from the same protostellar cloud. Therefore, they must be of the same age.
How to explain that luminaries of different ages formed a binary system? Did Polyarnaya A once capture a star passing by in a gravitational captivity? Such an event is almost impossible. Two stars rarely come so close together. But gravitational capture also requires a third, otherwise a potential captive will simply fly around the “invader” and hide in space distances.
Two birds with one stone
Curiously, the answer to both questions may be the same. And there are even two options for such an answer: the mistake of researchers or the unusual story of Polar.
This luminary is quite difficult to study. As noted in LiveScience , most telescopes are designed for much dimmer objects than the second magnitude star. The polar one for them is simply dazzlingly bright. On the other hand, humanity is also successfully exploring much brighter stars .
In addition, due to its position in the sky, Polyarnaya is out of sight of most instruments. But this does not mean that she was never observed. The fact that the mass of the star was determined in two ways suggests a variety of observational data.
Of course, this may not be about the quality of the data, but about an error in their interpretation. Man, as you know, tends to make mistakes. However, there is a more intriguing version.
The authors of the new study believe that a few million years ago in the system there were not three, but four stars. Then two of them collided, forming the present Polar A. Svetila, formed as a result of such collisions , do not fit into the classical models of star evolution.
Therefore, these theories cannot correctly indicate either the mass or age of the luminary.
However, such a cataclysm is extremely unlikely, so this explanation is difficult to find convincing, in any case, without additional data. The star of the north still holds its secrets.
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The article is written and prepared by our foreign editors from different countries around the world – material edited and published by Ordo News staff in our US newsroom press.