Sharpest image of most massive known star reveals its true size

Astronomers have taken the sharpest images ever of the most massive star in the known universe. With these new images, the scientists were able to refine just how big this star is, and in the process revise our ideas of how big it’s possible for stars to ever get.

more…

Tau.Neutrino said:

Sharpest image of most massive known star reveals its true size

Astronomers have taken the sharpest images ever of the most massive star in the known universe. With these new images, the scientists were able to refine just how big this star is, and in the process revise our ideas of how big it’s possible for stars to ever get.

more…

Which one is that? Checks link.

> R136a1 in the Tarantula Nebula. Previous observations have estimated its mass to be between 250 and 320 times that of the Sun, making it comfortably the most massive known star.

There are some huge stars in the Tarantula Nebula. I hadn’t know that one was the most massive.

> Gemini South telescope in Chile, performing a type of observation called speckle imaging.

That’d work. Normally adaptive optics are used on Gemini South instead of speckle imaging, but with a bright source like this, speckle imaging can be as good, or better.

Good resolution!

> calculate R136a1’s mass more precisely. They found that it’s probably only between 170 and 230 solar masses.

“Only”, hmm.

> It could also indicate that the upper limit for possible star masses is lower than previously thought, which would mean that certain types of supernova would be rarer, which in turn would affect the abundance of metals in the universe.

Agree.

Just out of interest, how heavy is Eta Carinae? 30 to 80 solar masses. We could do with narrowing the margins on that one.

mollwollfumble said:

Tau.Neutrino said:

Sharpest image of most massive known star reveals its true size

Astronomers have taken the sharpest images ever of the most massive star in the known universe. With these new images, the scientists were able to refine just how big this star is, and in the process revise our ideas of how big it’s possible for stars to ever get.

more…

Which one is that? Checks link.

> R136a1 in the Tarantula Nebula. Previous observations have estimated its mass to be between 250 and 320 times that of the Sun, making it comfortably the most massive known star.

There are some huge stars in the Tarantula Nebula. I hadn’t know that one was the most massive.

> Gemini South telescope in Chile, performing a type of observation called speckle imaging.

That’d work. Normally adaptive optics are used on Gemini South instead of speckle imaging, but with a bright source like this, speckle imaging can be as good, or better.

Good resolution!

> calculate R136a1’s mass more precisely. They found that it’s probably only between 170 and 230 solar masses.

“Only”, hmm.

> It could also indicate that the upper limit for possible star masses is lower than previously thought, which would mean that certain types of supernova would be rarer, which in turn would affect the abundance of metals in the universe.

Agree.

Just out of interest, how heavy is Eta Carinae? 30 to 80 solar masses. We could do with narrowing the margins on that one.

I wonder why they would put the “before” on the right.

Given that the heavier the star, the shorter the lifetime. I wonder how long before this goes supernova.

And how old it is now.

A star’s lifetime is proportional to its mass divided by its luminosity.

A quick estimate for lifetime is 200,000 years. Fairly long by human standards. The article may have a more accurate value.

mollwollfumble said:

Given that the heavier the star, the shorter the lifetime. I wonder how long before this goes supernova.

And how old it is now.

A star’s lifetime is proportional to its mass divided by its luminosity.

A quick estimate for lifetime is 200,000 years. Fairly long by human standards. The article may have a more accurate value.

The Internet tells me that a star’s luminosity is proportional to its mass, so it seems its lifetime should be proportional to mass/mass.

The Rev Dodgson said:

mollwollfumble said:

Given that the heavier the star, the shorter the lifetime. I wonder how long before this goes supernova.

And how old it is now.

A star’s lifetime is proportional to its mass divided by its luminosity.

A quick estimate for lifetime is 200,000 years. Fairly long by human standards. The article may have a more accurate value.

The Internet tells me that a star’s luminosity is proportional to its mass, so it seems its lifetime should be proportional to mass/mass.

OTOH, this site:
https://rechneronline.de/planets/lifespan-star.php

says lifespan is proportional to 1/(M^2.5)

(well actually say its M-2,5, but 1/(M^2.5) is what the calculator uses.

The Rev Dodgson said:

The Rev Dodgson said:

mollwollfumble said:

Given that the heavier the star, the shorter the lifetime. I wonder how long before this goes supernova.

And how old it is now.

A star’s lifetime is proportional to its mass divided by its luminosity.

A quick estimate for lifetime is 200,000 years. Fairly long by human standards. The article may have a more accurate value.

The Internet tells me that a star’s luminosity is proportional to its mass, so it seems its lifetime should be proportional to mass/mass.

OTOH, this site:
https://rechneronline.de/planets/lifespan-star.php

says lifespan is proportional to 1/(M^2.5)

(well actually say its M-2,5, but 1/(M^2.5) is what the calculator uses.

Thanks for that. So my estimate of a 200,000 year lifespan is a big overestimate.
This star will live for a much shorter time than that.

A star with 40 solar masses lives for a million years. 200 solar masses is 5 times as large, so the lifespan drops by a factor of 5^2.5 = 56. A 56th of a million years is a lifespan of only 18,000 years.

mollwollfumble said:

The Rev Dodgson said:

The Rev Dodgson said:

The Internet tells me that a star’s luminosity is proportional to its mass, so it seems its lifetime should be proportional to mass/mass.

OTOH, this site:
https://rechneronline.de/planets/lifespan-star.php

says lifespan is proportional to 1/(M^2.5)

(well actually say its M-2,5, but 1/(M^2.5) is what the calculator uses.

Thanks for that. So my estimate of a 200,000 year lifespan is a big overestimate.
This star will live for a much shorter time than that.

A star with 40 solar masses lives for a million years. 200 solar masses is 5 times as large, so the lifespan drops by a factor of 5^2.5 = 56. A 56th of a million years is a lifespan of only 18,000 years.

If the M^-2.5 thing is right :)

cool so we could see some fireworks soon