Den 28.09.2024 04:34, skrev rhertz:

This link illustrates a bit:

https://en.wikipedia.org/wiki/Gravitational_redshift

Using the most common formula from that link: "To first approximation, gravitational redshift is proportional to the difference in
gravitational potential divided by the speed of light squared"

Δf/f = Δλ/λ = z = GM/c² (1/R - 1/r) = Φ(R)/c² - Φ(r)/c²

G = 6.6743E−11 m^3 kg^−1 s^−2
M = 5E+09 x 1.989E+30 Kg = 9.945E+39 Kg
R = 1,700 x 634,000 Km = 1,077,800,000,000 m

The mass is 'only' ~30 times the mass of Sun

M = 30 x 1.989E+30 kg = 5.967e+31 kg

Φ(R)/c² = 6,842,736.59

In comparison, Φ(RSun)/c² = 0.000002327

At r = 10,000,000 R = 10,077,800,000,000,000,000 m

Φ(r)/c² = 0.684273659

Δf/f = Δλ/λ = z = 6,842,736

The z-value can be expressed succinctly in terms of the escape velocity
at R, since the gravitational potential is equal to half the square of
the escape velocity, thus:

z = 1/2 (v_escape/c)²

v_escape = 3699.4 c

But then, light can escape from UY Scuti.

Yet, it was discovered in 1860.

WHAT IS WRONG WITH MY CALCULATIONS, BASED ON THE WIKI LINK?

--
Paul

https://paulba.no/

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Den 28.09.2024 04:34, skrev rhertz:

This link illustrates a bit:

https://en.wikipedia.org/wiki/Gravitational_redshift

Using the most common formula from that link: "To first approximation, gravitational redshift is proportional to the difference in
gravitational potential divided by the speed of light squared"

Δf/f = Δλ/λ = z = GM/c² (1/R - 1/r) = Φ(R)/c² - Φ(r)/c²

Δλ/λ = GM/Rc² observed at infinity (r -> ∞)

https://www.space.com/41290-biggest-star.html

G = 6.6743E−11 m^3 kg^−1 s^−2
M = 5E+09 x 1.989E+30 Kg = 9.945E+39 Kg
R = 1,700 x 634,000 Km = 1,077,800,000,000 m

Φ(R)/c² = 6,842,736.59

From whence did you get the idiotic idea that the mass
of UY Scuti was 5 billion solar masses? :-D

M = 30 solar masses = 5.967e31 kg
R = 696340e3⋅1700 m = 57868e6 m
c = 299792458 m/s

Δλ/λ = GM/Rc² = 7.65e-7

Which is less than the red shift from the Sun.

In comparison, Φ(RSun)/c² = 0.000002327

M = 1.989E+30 kg
R = 696340e3 m

Δλ/λ = GM/Rc² = 2.12e-6

WHAT IS WRONG WITH MY CALCULATIONS, BASED ON THE WIKI LINK?

Now you know.

--
Paul

https://paulba.no/

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Paul.B.Andersen <relativity@paulba.no> wrote:

Den 28.09.2024 04:34, skrev rhertz:

This link illustrates a bit:

https://en.wikipedia.org/wiki/Gravitational_redshift

Using the most common formula from that link: "To first approximation, gravitational redshift is proportional to the difference in
gravitational potential divided by the speed of light squared"

?f/f = ??/? = z = GM/c? (1/R - 1/r) = ?(R)/c? - ?(r)/c?

??/? = GM/Rc? observed at infinity (r -> ∞)

https://www.space.com/41290-biggest-star.html

G = 6.6743E?11 m^3 kg^?1 s^?2
M = 5E+09 x 1.989E+30 Kg = 9.945E+39 Kg
R = 1,700 x 634,000 Km = 1,077,800,000,000 m

?(R)/c? = 6,842,736.59

From whence did you get the idiotic idea that the mass
of UY Scuti was 5 billion solar masses? :-D

M = 30 solar masses = 5.967e31 kg
R = 696340e3?1700 m = 57868e6 m
c = 299792458 m/s

??/? = GM/Rc? = 7.65e-7

Which is less than the red shift from the Sun.

In comparison, ?(RSun)/c? = 0.000002327

M = 1.989E+30 kg
R = 696340e3 m

??/? = GM/Rc? = 2.12e-6

WHAT IS WRONG WITH MY CALCULATIONS, BASED ON THE WIKI LINK?

Now you know.

He is looking for trouble where none exists.
Even for neutron stars you get a nice finite gravitational redshift,
which is 'easily' observable. For example: <https://pubmed.ncbi.nlm.nih.gov/12422210/>

They find a redshift value of z = 0.35 ,
which is consistent with standard neutron star models,
(but not with some exotic ones)

Jan

(such a large gravitational redshift dwarfs any possible Doppler shift)

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rhertz <hertz778@gmail.com> wrote:

On Sun, 29 Sep 2024 11:42:18 +0000, Paul.B.Andersen wrote:

Den 28.09.2024 04:34, skrev rhertz:

This link illustrates a bit:

https://en.wikipedia.org/wiki/Gravitational_redshift

Using the most common formula from that link: "To first approximation,
gravitational redshift is proportional to the difference in
gravitational potential divided by the speed of light squared"

?f/f = ??/? = z = GM/c? (1/R - 1/r) = ?(R)/c? - ?(r)/c?

??/? = GM/Rc? observed at infinity (r -> ∞)

https://www.space.com/41290-biggest-star.html

G = 6.6743E?11 m^3 kg^?1 s^?2
M = 5E+09 x 1.989E+30 Kg = 9.945E+39 Kg
R = 1,700 x 634,000 Km = 1,077,800,000,000 m


?(R)/c? = 6,842,736.59

From whence did you get the idiotic idea that the mass
of UY Scuti was 5 billion solar masses? :-D

M = 30 solar masses = 5.967e31 kg
R = 696340e3?1700 m = 57868e6 m
c = 299792458 m/s

??/? = GM/Rc? = 7.65e-7

Which is less than the red shift from the Sun.

In comparison, ?(RSun)/c? = 0.000002327

M = 1.989E+30 kg
R = 696340e3 m

??/? = GM/Rc? = 2.12e-6

WHAT IS WRONG WITH MY CALCULATIONS, BASED ON THE WIKI LINK?

Now you know.

***************************************************************
QUOTE:
--------------------------------------------------------------------
The biggest star in the universe (that we know of), UY Scuti is a
variable hypergiant with a radius around 1,700 times larger than the
radius of the sun.

To put that in perspective, the volume of almost 5 billion suns could
fit inside a sphere the size of UY Scuti.

The star lies near the center of the Milky Way, roughly 9,500
light-years away from Earth. Located within the constellation Scutum, UY Scuti is a hypergiant star. Hypergiants — larger than supergiants and giants — are rare stars that shine very brightly. They lose much of
their mass through fast-moving stellar winds.

https://www.space.com/41290-biggest-star.html **************************************************************

You didn't even try to read the OP, from where I extracted the data,
idiot.

This is another link:

Star UY Scuti is so big, you could fit 5 billion Suns inside it

https://www.skyatnightmagazine.com/space-science/uy-scuti

Here it's claimed that they don't have a clue about its mass:

https://en.wikipedia.org/wiki/UY_Scuti

So, rela-astrophysicists come out with any shit, as they are not
accountable for what they publish.

Reading isn't your strongest point, is it?
By Wikipedia, the best mass estimate is smaller than 10 solar masses,
with a radius probably extending beyond Mars.
This implies a negligeable gravitational red shift,
so the answer to your question is: red, red, and red,

Jan

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Den 29.09.2024 19:02, skrev rhertz:

On Sun, 29 Sep 2024 11:42:18 +0000, Paul.B.Andersen wrote:

 From whence did you get the idiotic idea that the mass
of UY Scuti was 5 billion solar masses? :-D

M = 30 solar masses =  5.967e31 kg
R = 696340e3⋅1700 m = 57868e6 m

correction: R = 1183778e6

c = 299792458 m/s

Δλ/λ = GM/Rc² = 7.65e-7

Δλ/λ = GM/Rc² = 3.74e-8

even smaller!

Which is less than the red shift from the Sun.

In comparison, Φ(RSun)/c² = 0.000002327

M = 1.989E+30 kg
R = 696340e3 m

Δλ/λ = GM/Rc² = 2.12e-6

WHAT IS WRONG WITH MY CALCULATIONS, BASED ON THE WIKI LINK?

Now you know.

***************************************************************
QUOTE:
--------------------------------------------------------------------
The biggest star in the universe (that we know of), UY Scuti is a
variable hypergiant with a radius around 1,700 times larger than the
radius of the sun.

To put that in perspective, the volume of almost 5 billion suns could
fit inside a sphere the size of UY Scuti.

Now I know from where you got the idiotic idea that the mass of
UY Scuti was 5 billion solar masses.

I will give you a hint:
(Rsun⋅1700)³/Rsun³ = 4.913e9

You have to be _very_ ignorant to believe that all stars
have the same density.

All stars, including UY Scuti, has once been
a main sequence star with 'normal' size.
A typical O-star in the main sequence has ~ 200 solar masses.

The most massive star known has ~ 300 solar masses

Giants and Super-giants are stars at the end of their
life when they increase in size before they go supernova,
or shrinks to red dwarfs when all the 'fuel' is burned (fusion).

In five million years the Earth will be inside the Sun,
and at that time it will have lost much of its mass,
and will have a density much less than now.

The star lies near the center of the Milky Way, roughly 9,500
light-years away from Earth. Located within the constellation Scutum, UY Scuti is a hypergiant star. Hypergiants — larger than supergiants and giants — are rare stars that shine very brightly. They lose much of
their mass through fast-moving stellar winds.

https://www.space.com/41290-biggest-star.html **************************************************************

I quote:
"UY Scuti's large radius does not make it the most massive,
or heaviest, star. That honor goes to R136a1, which weighs in
at about 300 times the mass of the sun but only about 30 solar radii.
UY Scuti, in comparison, is only about 30 times the mass of the sun,
but far greater in volume."

You didn't even try to read the OP, from where I extracted the data,
idiot.

I can do what you have demonstrated over and over you can't;
read a text _properly_ and understand what it says.

This is typical Richard Hertz.
He doesn't consider the possibility of being wrong's even
when the correction is shoved into his face.

This make your error into a giant blunder.

So, rela-astrophysicists come out with any shit, as they are not
accountable for what they publish.

But you have got it now, haven't you?

Your giant blunder was to take it for granted that all stars
have the same density, and found it reasonable that the mass
of UY Scuti was 5 billion solar masses. :-D


--
Paul

https://paulba.no/

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Den 29.09.2024 20:49, skrev rhertz:

i'm very good at reading and I'm confident about people extracting the correct information from the links I post. I don't censure anything.

This is the link in your OP:
https://www.space.com/41290-biggest-star.html

Quote of relevant parts:

"The biggest star in the universe (that we know of), UY Scuti
is a variable hypergiant with a radius around 1,700 times
larger than the radius of the sun.
To put that in perspective, the volume of almost 5 billion
suns could fit inside a sphere the size of UY Scuti."

"UY Scuti's large radius does not make it the most massive,
or heaviest, star. That honor goes to R136a1, which weighs in
at about 300 times the mass of the sun but only about 30 solar radii.
UY Scuti, in comparison, is only about 30 times the mass of the sun,
but far greater in volume."

So this link you posted give R = 1700 solar radii and
M = 30 solar masses.

But the data _you_ extracted from the link was:

Den 28.09.2024 04:34, skrev rhertz:
| G = 6.6743E−11 m^3 kg^−1 s^−2
| M = 5E+09 x 1.989E+30 Kg = 9.945E+39 Kg
| R = 1,700 x 634,000 Km = 1,077,800,000,000 m

So no, you are not very good at reading.

People (like me) did indeed extract the right information
from the link in your posted, but YOU DID NOT!

And what's worse, you _accepted_ that the mass is 5 billion
solar masses without wondering if it was possible!
Your ignorance is unbelievable!

And what's even worse is that when I told you that you had
got the mass wrong, you responded:
"You didn't even try to read the OP, from where I extracted
the data, idiot."

Who is the idiot? :-D

Again and again you demonstrate your inability to read
a text and understand what you read.

------------------------

I have however looked closer for information about UY Scuti

This is from a star catalogue:
https://www.stellarcatalog.com/stars/uy-scuti
It gives the data:
R = 1708 solar radii, Mass = 8 solar masses.

This seems to be the newest (2024-03-10):
https://www.star-facts.com/uy-scuti/
Quote:
" UY Scuti is a previous record holder for the largest star known.
The supergiant star was believed to lie at a much greater distance
– 9,500 light-years away – and had an estimated radius of 1,708 solar
radii. More recent studies place it much closer and give it a smaller
size."
"The estimated mass of UY Scuti is between 7 and 10 times the mass
of the Sun."
"UY Scuti has a radius about 909 times that of the Sun."

With M = 8 solar masses and R = 909 solar radii we get the red shift:

Δλ/λ = GM/Rc² = 1.87e-8

This is equivalent to the Doppler shift from a star receding
at the speed 5.6 m/s.

Since the radial velocity of the star is 18.33 ± 0.82 km/s,
the uncertainty in the Doppler shift due to the motion of the star
will dwarf the gravitational red shift.

You know of course how they measure the Doppler shift from
a star. Offset of absorption lines, Balmer series, etc.

ONE MORE TIME, I EXTRACT THIS PART. BE HONEST:

From Wikipedia, two different values for mass and a remarkable "MASS IS UNKNOWN":

https://en.wikipedia.org/wiki/UY_Scuti

The luminosity is then calculated to be 340,000 L☉ at an effective temperature of 3,365±134 K, giving an initial mass of 25 M☉ (possibly up to 40 M☉ for a non-rotating star).[4]
.....

UY Scuti has no known companion star and so its mass is uncertain.
However, it is expected on theoretical grounds to be between 7 and 10 M☉.[4]

***********************

7, 10, 25, 1,000 M☉. Rela-astrophysicists DON'T HAVE A CLUE!

Aren't they in the club that affirm that baryonic matter in the Universe accounts for only 5% of what BBT/GR requires?

And these geniuses try to calculate mass by using luminosity and 150
years old formulae. Theoretical astrophysics IS AN ABSOLUTE JOKE, since
the times of Stefan, later with Eddington.

Don't you think Stefan–Boltzmann law is applicable today? :-D

You have demonstrated that you are utterly ignorant of astronomy
and astrophysics.

If you had more than one neuron, you wouldn't claim
that experts in a field you know _nothing_ about were idiots.


--
Paul

https://paulba.no/

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