What is A New, Surprising Insight into the greatest star?
The clearest pictures yet acquired of the brightest star suggest that the maximum mass attributed to the Sun is likely much lower than prior estimations.
Initially, the mass of this star ( R136a1) was estimated to be between 250 and 320 times that of the Sun. This latest calculation puts its mass between 150 and 230 times that of the Sun.
The star's mass has been revised and reduced to around 200 solar masses, which is still a heavyweight record, but this new estimate may have more far-reaching consequences.
This study was conducted as part of a larger effort to learn more about the R136 cluster. It is located in the Large Magellanic Cloud, a satellite galaxy of our Milky Way, and home to the star-forming Tarantula Nebula.
Some massive stars in the universe are located in this cluster, and their masses have recently been revised downwards along with everything else. Our previous stellar upper mass limitations may be incorrect, as these masses are crucial anchor points for the upper mass function of massive stars, which was predicted by this work.
Observations made at the Gemini Observatory have led astronomer and astrophysicist Venu Kalari to conclude that the most massive star currently known is not as large as was previously supposed. Because of this, the maximum allowed star mass may be lower than was previously believed.
Calculations and models show that there must be a maximum star mass, but we don't know what it is. At a certain point, called the Eddington limit, it is generally agreed that the outward pressure from the core's radiation will exceed the inward gravitational pressure, causing material in the star's outer layers to be ejected.
In the past, researchers have determined that the Eddington limit cannot exceed 150 solar masses. Later, more accurate mass estimates for the R136 stars were obtained.
These young, extremely hot, and enormous stars contradicted the Eddington limit and stellar formation theories. We still don't have a solid answer to the Eddington limit problem, even though subsequent studies established that such chokers can arise due to star mergers.
A significant step toward resolving this vexing mystery would be to agree on a maximum mass based on reliable reference points. Accurate measurements of a star's luminosity and temperature estimate its mass. So Kalari and his team set out to get new, higher-resolution photos of the cluster and R136a1.
It provided the data necessary for the researchers to determine that R136a1 has a new mass of 196 solar masses (plus or minus a few dozen sun masses). R136a2 and R136a3 had new masses of 151 and 155 solar masses, down from 195-211 and 180-181, respectively.
It affects the heavy element production in the universe. You may know that large stars can eventually collapse into black holes after ejecting their outer material. But there is a limit: if the star's mass is greater than 130 solar masses, it can undergo a pair-instability supernova and explode completely, core and all.
Subatomic reactions create heavy materials during these extremely intense occurrences. We must reevaluate the possible contribution of pair-instability supernovae to the heavy elements we witness in space if fewer stars exist in this mass range.
Because a single pair-instability supernova from a star of 300 solar mass would release more metals into the interstellar medium than an entire stellar mass function below it, the existence or absence of such events "cannot be overemphasised," the researchers write in their paper.
This discovery was obtained using the Zorro instrument on the Gemini South telescope to its maximum capacity. Hence the researchers advise against jumping to any hasty conclusions.
The following step would be validating the findings by obtaining and comparing observations from a different instrument.
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