Astronomers using various instruments at the Very Large Telescope of the European Southern Observatory (ESO) managed to discover the heaviest stars to date, with one of them 300 times heavier than the Sun, or twice the upper limit thought to be 150 solar masses.
Using the Very Large Telescope (VLT), as well as archival data from the Hubble Space Telescope, a team of astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield in the UK, studied two young star clusters NGC 3603 and RMC 136a in great detail. NGC 3603 is a cosmic factory where stars form from the vast clouds of gas and dust that make up the nebula located 22 thousand light years from us.
RMC 136a or simply R136 is another young nebula containing massive and hot stars located within the Tarantula Nebula in one of the neighboring galaxies of the Milky Way - in the Large Magellanic Cloud 165 thousand light years away.
The team discovered several stars whose surface temperature is higher than 40 degrees Celsius - or 7 times hotter than the Sun, which are also tens of times more massive and several million times brighter than the Sun. The model so far talked about the maximum that a star can reach is 150 solar masses. The star, R136a1, discovered in the R136 cluster is the most massive star discovered so far, when its birth mass was 320 solar masses and today it weighs only 265 solar masses.
In NGC 3603, the astronomers were also able to directly measure the masses of two stars belonging to a binary star system, in order to validate the model. The stars A1, B and C in this cluster are estimated to have a birth mass of about 150 solar masses.
"Very massive stars produce a strong wind. Unlike humans, stars are born heavy and lose weight with age," Crowther said. "Although he is a million years old in total R136a1 is already middle-aged and is on a massive weight loss program. It has already shed a fifth of its original mass over time - a mass equal to fifty solar masses."
"If R136a1 were to replace the sun in the solar system it would eclipse the sun as much as the sun eclipses the full moon. "Its high mass would shorten the Earth's year by three weeks, and would immerse the Earth in strong ultraviolet radiation, making life on Earth impossible," said Rafael Hirschi from Kiel University, a member of the team.
These super-massive stars are rare, they form but sporadically in compact clusters. Separating the individual stars – something that has now been achieved for the first time – requires the fine resolution of the VLT's infrared instruments.
The team also estimated the maximum possible mass of stars within these clusters and a relatively small number of other massive clusters. "The smallest stars are limited to 80 times the size of Jupiter. Below that are failed stars or brown dwarfs," says team member Oliver Schnorr of the Institute for Astrophysics in Potsdam, Germany. "The new findings support the model so far that there is an upper limit to the mass of stars, although the number has increased by a factor of two to about 300 solar masses.
Within R136, only four stars were heavier than 150 solar masses at birth, but they are responsible for half of the solar wind and radiation intensity of the entire cluster, numbering about 136 stars. R1a60 radiates energy into its surroundings XNUMX times more than the intensity of energy in the Orion Nebula, the closest star-forming region to Earth.
"Understanding the question of how such massive stars are formed is an enigma in itself, due to their short life span and the strong wind they create, therefore identifying extreme cases such as R136a1 raise the challenge of the theories to another level. "Either they are born so big or small stars merge together to form them." Crowther explains.
For information on the Southern European Observatory website
18 תגובות
http://en.wikipedia.org/wiki/Eddington_limit
I would appreciate it if someone would translate it
It's fascinating... such a big star... does this mean that if we find an even bigger star there is a possibility that we can see a continuous and complete supernova process during the lifetime of a human being?... we can see the whole life of the star maybe?
Michael
There is a fairly comprehensive entry on the subject of the vane (Crookes radiometer) on Wikipedia.
The phenomenon is certainly interesting and also has implications for the rotation of asteroids. appear to be
Because solar radiation causes asteroids to spin on their axis and sometimes causes disintegration
The asteroid into smaller pieces following the rotation. There is a PhD student named David
Polishok at Tel Aviv University who researches the field.
sympathetic:
Thanks for the explanation regarding the vane.
I remember that in my childhood my father brought home such a Shabbat and gave Crooks' explanation.
I remember even then it didn't make sense to me - precisely because of the illumination of the dark side - but I had no one to talk to and over the years I forgot the story and did not investigate it again.
deer
Regarding response 11
I too have heard the claims that stars of this type collapse into black holes, and I agree if these claims.
There is also a claim that there is a civilization that knows how to control all types of energy in the universe.
If we assume that this is true, then we can make the claim that it is probably the civilization that creates these massive stars and then explodes them (or waits for them to explode on their own) and in this way creates black holes in order to move to parallel universes.
It's not just that civilization is at the distance (or border) where it is.
: )
Interesting, the truth is that you can do a quantitative calculation and try to estimate how strong it is, thanks anyway
deer
Thank you for your wise comments that greatly improve the experience of reading the articles on the site. I just wanted to point out a small correction. The small experiments that you sometimes see in museums or on YouTube do not demonstrate radiation pressure. The rotating vane as a result of illumination is called a Crookes radiometer. The vane rotates not by the radiation pressure but as a result of the heating of the surface and the resulting formation of air currents leading to the rotation. This can be learned from the dependence of the rotation of the vane on the quality of the vacuum, when the vacuum is too "good" the vane does not turn because there are not strong enough air currents, when there is not "enough" vacuum it also does not turn because the friction is too high. Another evidence that it is not radiation pressure is the "opposite" direction of rotation. The vane rotates when the push to rotate comes from the black side and not the shiny side. If it were radiation pressure, the shiny side would get more momentum since it reflects the photons and does not absorb them.
By the way, Crooks' explanation for the phenomenon was that he mistakenly claimed that the vane rotates as a result of radiation pressure. This explanation was also supported by Maxwell who predicted such a phenomenon. Only at the beginning of the XNUMXth century were experiments done demonstrating that the reason for rotation is different.
Ami and Ethan,
A star with a mass of more than 8 solar masses indeed sometimes ends its life in a supernova, but not always - sometimes more interesting things happen (maybe?)
I do not know what will happen to such a monstrous star because it is really very special, in any case, normal stars of all sizes swell and become giants after they have used up the hydrogen in them.
That's when the process of burning helium to carbon and oxygen begins and then continues (if the stars are massive enough) to other materials that are heavier and heavier until a peak in iron or nickel (depending on the pressures).
At some point, the core of the star collapses and then a supernova occurs and the story is familiar. However, stars that have gone supernova remain as neutron stars while such massive stars do not end their lives as neutron stars but as black holes.
There are probably fairly accepted claims, according to which some of the Gamma Ray Bursts originate from a massive star collapsing into a black hole - if this is the case then the star in front of us will not end its life in a supernova and then a neutron star but in a GRB and then a black hole
For sure, to the best of my recollection, a star that grew over eight solar masses will go supernova at the end of its life and the elements in it (from hydrogen to iron) will fly in all directions.
What will happen to this star at the end of its days?
Will he grow more?
Another note regarding Blog's comments,
Each star is held in balance between gravity pulling in and pressure pushing out.
The pressure consists of two components, the radiation pressure and the gas pressure (thermal pressure like in a balloon).
In large stars, the radiation pressure is dominant
In small stars (such as the Sun) - the gas pressure is dominant
The Eddington luminosity for the mass of the sun, for example, is ~30,000 times higher than the luminosity of the sun, and if it weren't for the gas pressure, it would collapse
Yair,
Beetlejuice is not a star of the main series but a giant at the end of his days, and therefore the sacrifice to him is not correct
Blog's explanation for the maximum limit of a star's radiation is correct (with the exception of his statement that the theoretical limit needs to be reformulated) and it can even be explained relatively simply:
According to the electromagnetic theory, the electromagnetic field has energy and therefore light (electromagnetic radiation) has momentum.
There are very simple experiments that are sometimes shown in science museums (and I'm pretty sure on YouTube as well) in which they show a small shabbat that rotates when projected onto it with a projector.
In light of this, we will look at an infinitesimal mass of matter on the edge of a star. The mass of matter is pulled (by gravity) with an intensity proportional to the star's mass, on the other hand, it is "pushed" by the momentum of light with an intensity proportional to the star's illumination. Thus, we can conclude that the maximum illuminance that will not begin to disintegrate the star, is obtained by comparing the two forces and thus we will obtain the Eddington illuminance - proportional to the mass of the star. Hence, if the luminosity of the star increases for any reason in a ratio higher than a direct ratio to the mass (and this is the case), then a certain maximum limit is obtained for the mass of a star.
In practice, there are many bodies that illuminate with a luminosity higher than the Eddington luminosity and there are also quite a few stars that do so (if I'm not mistaken, the maximum mass for a star according to such a simple calculation is about 18 solar masses, far below the upper limit for a star) - how does this happen?
In this calculation we assumed that the body has numerical symmetry - that is, if you take a shell at a distance R from the center, the whole shell is the same, in practice - there are good reasons why this will not hold, and if you assume an inhomogeneous medium (small disturbances in density) you can get an illuminance higher than the illuminance of Addington. The price of this is in the creation of "Spirit", which in practice is slowly disintegrating the star as described in the article.
Apparently, it is possible to use such a trick of inhomogeneity to transmit infinitely high illumination (for a very strong inhomogeneity), but it is necessary to explain how a situation will arise in which the medium is not homogeneous. The mechanisms that describe the creation of the inhomogeneity are very complicated and difficult to calculate and it seems that until now the model predicted the creation of an inhomogeneity that would allow the transfer of up to X times the Eddington luminosity (corresponding to 150 solar masses) and now it has been found that it is possible to transfer up to Y times the Eddington luminosity (corresponds to 300 solar masses).
There is therefore no significant change here in the theory predicting a maximum limit to illumination, but only a change in the quantitative value of the degree of inhomogeneity that allows more to be transmitted.
It's nice and interesting, but not a break in everything we knew.
Those numbers sound surprisingly low to me.
In terms of volume, there are huge stars - the diameter of Bitelgus is about 700 times the diameter of the Sun (as volume ratios are about 700 to the power of three, or 343,000,000). I never understood which stars have such a low density compared to the Sun.
This sun is simply unimaginable.. The universe amazes me every time
simply incredible
Answer to Ami:
Each star is balanced by 2 forces - gravity, which pulls in, and the radiation it produces, which pushes out. The more massive a star is, the more intense radiation it produces. There is a theoretical limit to the radiation that a star can produce, without disintegrating itself into its elements (this is called "Eddington radiation").
Apparently there are some stars that violate the Eddington limit, yet do not break up. It might be worth re-drafting this theoretical limit.
It seems to me that at some point gravity stops having an effect, this is the "limit" of the star. Although I'm not sure.
Why should there be an upper limit to the size of a star? What prevents gas from compacting into a star?