Main Sequence Stellar Mass Function?

In rec.arts.sf.science Golden California Girls wrote:
Michael Ash wrote:
In rec.arts.sf.science BradGuth wrote:
On Nov 3, 1:04 pm, Erik Max Francis wrote:
BradGuth wrote:
On Nov 2, 11:18 pm, Erik Max Francis wrote:
BradGuth wrote:
Why couldn't a white dwarf eventually become a massive but small brown
dwarf?
Because that's not what the words mean. What's one mile north of the
North Pole? What exists inside a thing which doesn't exist? Why
couldn't a feeling of dread become an earthworm? Why couldn't an old
man become a zygote? Why couldn't this chair become a galaxy? Why do
you still crosspost your crank **** here?
Just because your universe is only 13.5 billion years old isn't my
fault.
I'm reminded of a character from the comedy show NewsRadio: "Don't
confuse me with the facts!"

To me a brown dwarf can just as easily be and old white dwarf instead
of a 10x Jupiter.
Perhaps, if you don't know what the terms actually mean as used by
astronomers. Which you obviously don't. But then, effective
communication is not exactly high on your list of priorities.

What else should we call an old white dwarf? (a dull dwarf?, a cold
dwarf?)
There's already a name for that: a black dwarf.
It takes a great deal of time to reach the black dwarf phase.
Somewhere in between white and black is brown.

Wow, you don't even share common vocabulary for *colors*? Astounding. Here
in reality, we call the colors which exist between white and black "gray".
(Or for our bretheren who speak the Queen's English, "grey".) Brown
requires an additional tint of yellow, orange or red to be added.

Gosh someone who doesn't know what blackbody radiation is.

Is "brown" a black-body color? I was not aware. Here I was thinking that
the colors went through a sequence from red to orange to white to blue.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

On Nov 3, 6:34 pm, Michael Ash wrote:
In rec.arts.sf.science BradGuth wrote:



On Nov 3, 1:04 pm, Erik Max Francis wrote:
BradGuth wrote:
On Nov 2, 11:18 pm, Erik Max Francis wrote:
BradGuth wrote:
Why couldn't a white dwarf eventually become a massive but small brown
dwarf?
Because that's not what the words mean. What's one mile north of the
North Pole? What exists inside a thing which doesn't exist? Why
couldn't a feeling of dread become an earthworm? Why couldn't an old
man become a zygote? Why couldn't this chair become a galaxy? Why do
you still crosspost your crank **** here?
Just because your universe is only 13.5 billion years old isn't my
fault.

I'm reminded of a character from the comedy show NewsRadio: "Don't
confuse me with the facts!"

To me a brown dwarf can just as easily be and old white dwarf instead
of a 10x Jupiter.

Perhaps, if you don't know what the terms actually mean as used by
astronomers. Which you obviously don't. But then, effective
communication is not exactly high on your list of priorities.

What else should we call an old white dwarf? (a dull dwarf?, a cold
dwarf?)

There's already a name for that: a black dwarf.

It takes a great deal of time to reach the black dwarf phase.
Somewhere in between white and black is brown.

Wow, you don't even share common vocabulary for *colors*? Astounding. Here
in reality, we call the colors which exist between white and black "gray".
(Or for our bretheren who speak the Queen's English, "grey".) Brown
requires an additional tint of yellow, orange or red to be added.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

Was Sirius B ever a main sequence star?

~ BG

On Nov 4, 8:00 am, Michael Ash wrote:
In rec.arts.sf.science Golden California Girls wrote:



Michael Ash wrote:
In rec.arts.sf.science BradGuth wrote:
On Nov 3, 1:04 pm, Erik Max Francis wrote:
BradGuth wrote:
On Nov 2, 11:18 pm, Erik Max Francis wrote:
BradGuth wrote:
Why couldn't a white dwarf eventually become a massive but small brown
dwarf?
Because that's not what the words mean. What's one mile north of the
North Pole? What exists inside a thing which doesn't exist? Why
couldn't a feeling of dread become an earthworm? Why couldn't an old
man become a zygote? Why couldn't this chair become a galaxy? Why do
you still crosspost your crank **** here?
Just because your universe is only 13.5 billion years old isn't my
fault.
I'm reminded of a character from the comedy show NewsRadio: "Don't
confuse me with the facts!"

To me a brown dwarf can just as easily be and old white dwarf instead
of a 10x Jupiter.
Perhaps, if you don't know what the terms actually mean as used by
astronomers. Which you obviously don't. But then, effective
communication is not exactly high on your list of priorities.

What else should we call an old white dwarf? (a dull dwarf?, a cold
dwarf?)
There's already a name for that: a black dwarf.
It takes a great deal of time to reach the black dwarf phase.
Somewhere in between white and black is brown.

Wow, you don't even share common vocabulary for *colors*? Astounding. Here
in reality, we call the colors which exist between white and black "gray".
(Or for our bretheren who speak the Queen's English, "grey".) Brown
requires an additional tint of yellow, orange or red to be added.

Gosh someone who doesn't know what blackbody radiation is.

Is "brown" a black-body color? I was not aware. Here I was thinking that
the colors went through a sequence from red to orange to white to blue.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

How dark of brown are we talking about?

Our Selene/moon offers a physically dark golden brown that has the
average albedo of terrestrial coal.

What's the human visual level and otherwise that of IR photon
intensity (compared to our sun) of a brownish dwarf?

~ BG

On Nov 3, 11:35*am, BradGuth wrote:
On Oct 31, 8:16 am, Raghar wrote:

You want to integrate along the initial mass function to get a more
accurate figure, and then adjust for stellar evolution.

Actually in computer games, the most important thing are the main
sequence stars. While it might be convenient to have probabilities
even for white dwarfs and other excluded stuff, in majority of
computer games they don't interact thus they are irrelevant as
anything else as decoration, in the rest games the numbers could be
fudged easily.

A perfect paper for computer games would have a table with
probabilities of main sequence stars, and probabilities of the rest of
the stuff with respect to the amount of main seqence stars.

How about a game of Sirius B going red giant postal and then flashing
itself over into a white dwarf, losing its tidal radius grip on all of
its planets?

Is there any reason why Sirius B at 6 to 7 solar mass couldn't have
had Earth and Venus like planets, or even a trinary companion star
exactly like a certain main sequence that we call our sun?

Sir, what exactly are you talking about? How does that have the least
thing to do with a computer game? I don't mind you spewing your crazy
around, but do try to be on topic if possible.

On Nov 5, 8:36 am, wrote:
On Nov 3, 11:35 am, BradGuth wrote:



On Oct 31, 8:16 am, Raghar wrote:
You want to integrate along the initial mass function to get a more
accurate figure, and then adjust for stellar evolution.

Actually in computer games, the most important thing are the main
sequence stars. While it might be convenient to have probabilities
even for white dwarfs and other excluded stuff, in majority of
computer games they don't interact thus they are irrelevant as
anything else as decoration, in the rest games the numbers could be
fudged easily.

A perfect paper for computer games would have a table with
probabilities of main sequence stars, and probabilities of the rest of
the stuff with respect to the amount of main seqence stars.
How about a game of Sirius B going red giant postal and then flashing
itself over into a white dwarf, losing its tidal radius grip on all of
its planets?

Is there any reason why Sirius B at 6 to 7 solar mass couldn't have
had Earth and Venus like planets, or even a trinary companion star
exactly like a certain main sequence that we call our sun?

Sir, what exactly are you talking about? How does that have the least
thing to do with a computer game? I don't mind you spewing your crazy
around, but do try to be on topic if possible.

Shouldn't a SF computer game be at least somewhat based upon the best
available science, and otherwise function within the regular laws of
physics?

~ BG

BradGuth wrote:
On Nov 5, 8:36 am, wrote:
Sir, what exactly are you talking about? How does that have the least
thing to do with a computer game? I don't mind you spewing your crazy
around, but do try to be on topic if possible.

Shouldn't a SF computer game be at least somewhat based upon the best
available science, and otherwise function within the regular laws of
physics?

1. Not necessarily.

2. If so, then it probably would be helpful to start with knowing what
the terminology involved actually means. Hint, hint.

--
Erik Max Francis && && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
God does not play dice with the universe.
-- Albert Einstein

On Nov 5, 12:21 pm, Erik Max Francis wrote:
BradGuth wrote:
On Nov 5, 8:36 am, wrote:
Sir, what exactly are you talking about? How does that have the least
thing to do with a computer game? I don't mind you spewing your crazy
around, but do try to be on topic if possible.

Shouldn't a SF computer game be at least somewhat based upon the best
available science, and otherwise function within the regular laws of
physics?

1. Not necessarily.

2. If so, then it probably would be helpful to start with knowing what
the terminology involved actually means. Hint, hint.

--
Erik Max Francis && &&http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
God does not play dice with the universe.
-- Albert Einstein

Sounds more like a silly computer word game that isn't based upon the
best available science, and only needs to use conditional laws of
physics. Therefore, nothing matters, because it's all totally
subjective or simply bogus to start with.

~ BG

On Nov 5, 3:27 pm, BradGuth wrote:

Sounds more like a silly computer word game that isn't based upon the
best available science, and only needs to use conditional laws of
physics. Therefore, nothing matters, because it's all totally
subjective or simply bogus to start with.

Absolutely! The walking mushroom physics in the Super Mario Brothers
games were thoroughly researched for the most realistic mushroom
stomping action possible.

On a more serious note, there is a difference between a game and a
simulation. Some games are simulations, but even then absolute
adherence to science must take a back seat to gameplay. For example
you will note that while I was looking for a more realistic selection
of stellar masses for the game, I was happy that the numbers were not
exact since it was better for gameplay to potentially have more
habitable realestate.

On a more specific note, the function in question in this thread is an
“Initial Mass Function” which is to say the mass of a star at
formation. All bodies that are above the 0.08 solar mass point (Brown
Dwarfs that never initiate hydrogen fusion) start as “Main Sequence”
stars. Black holes, White Dwarfs (or gray or black dwarfs depending on
age), Pulsars/Neutron Stars, Red Giants, Super Giants, and a number of
other types are all Main Sequence Stars that have aged to a certain
point. This is all according to conventional stellar theories which
you may have no truck with, but work just fine for a game. (And the
universe at large, I’ll note.)

Since most of the stars in the local area are Population I (with a few
exceptions like Bernard’s Star) they are roughly the same age. I don’t
see the need to create an algorithm to age stars for the game. Well,
not yet, but feature creep exists even in one-man projects.

In article ,
Erik Max Francis writes:
The details of the "turnover" are error-prone enough that it's not clear
whether there really is a turnover, at least in terms of number density.
The initial mass function xi(M) as given in _Allen's Astrophysical
Quantities_ (p. 488) is...

There's been a lot of work done in the five years since _AAQ_ was
published, and according to the expert I asked, the turnover is
clear. As I say, though, this isn't a subject I follow. An ADS
search would no doubt turn up relevant papers. I'd expect many of
them to be based on 2MASS data.

I agree with the OP that for his purposes, game play is far more
important than accuracy. To the extent scientific accuracy is a
factor at all, he deserves lots of credit for having mostly M stars
and few B or A.

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)

On Nov 6, 7:17 am, wrote:
On Nov 5, 3:27 pm, BradGuth wrote:

Sounds more like a silly computer word game that isn't based upon the
best available science, and only needs to use conditional laws of
physics. Therefore, nothing matters, because it's all totally
subjective or simply bogus to start with.

Absolutely! The walking mushroom physics in the Super Mario Brothers
games were thoroughly researched for the most realistic mushroom
stomping action possible.

On a more serious note, there is a difference between a game and a
simulation. Some games are simulations, but even then absolute
adherence to science must take a back seat to gameplay. For example
you will note that while I was looking for a more realistic selection
of stellar masses for the game, I was happy that the numbers were not
exact since it was better for gameplay to potentially have more
habitable realestate.

On a more specific note, the function in question in this thread is an
“Initial Mass Function” which is to say the mass of a star at
formation. All bodies that are above the 0.08 solar mass point (Brown
Dwarfs that never initiate hydrogen fusion) start as “Main Sequence”
stars. Black holes, White Dwarfs (or gray or black dwarfs depending on
age), Pulsars/Neutron Stars, Red Giants, Super Giants, and a number of
other types are all Main Sequence Stars that have aged to a certain
point. This is all according to conventional stellar theories which
you may have no truck with, but work just fine for a game. (And the
universe at large, I’ll note.)

Since most of the stars in the local area are Population I (with a few
exceptions like Bernard’s Star) they are roughly the same age. I don’t
see the need to create an algorithm to age stars for the game. Well,
not yet, but feature creep exists even in one-man projects.

Sirius-B (a once upon a time 7+ solar mass) seems older than our sun,
and yet Venus seems less old than Earth.

How about putting in an icy proto-moon of 4000 km diameter, as having
roughly a 7.4 e22 kg rocky core into your interstellar game, and of
that icy sucker accommodating intelligent life getting away from one
solar system at the end of its red-giant demise, over to lithobraking
itself into another planet (such as Earth) within our solar system.

Don't make any of this game simple or without any number of highly
complex and nearly insurmountable considerations.

~ Brad Guth Brad_Guth Brad.Guth BradGuth BG / “Guth Usenet”