![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
What part of the star do the temperatures in this table refer to? Surface? Core? Could someone with the appropriate knowledge alter this for clarity? QmunkE 15:47, 10 March 2006 (UTC)
I had a thought the other day. And tried to find this answer to this on Wikipedia and other sources. But as a complete layman became very confused, parsecs/light years ect. This is my thought, we (the human race) have been sending out RF signals of a reasonable strength since 1922, please correct me on this if I have this wrong. Based on this knowledge, I wondered how far and how many star like suns (G class stars) have these RF signals reached by this year, 2007 ? You know where I'm going with this thought, and yes maybe life is not restricted to G class stars, or maybe it is, or maybe only to G2V, and we all known G2V's are capable! Then there's the age of these stars, and then the metallic make up as well. I wish someone with the right knowledge would draw up a list of theses stars. And using the above knowledge. We could then break the list up into the most lightly to the most unlikely places that intelligent life may exist. And that have also received RF signals from us. I believe this list would be helpful to SETI, to reduce their listing down to size, so they can focus on a more broader range of RF signals. As I also believe the RF's they are searching are far too narrow, and I feel a lot of time and money is going to waist at SETI. If anyone can help me with this please do, maybe I've got this wrong as I'm just a layman. But in any case, post me something, its bugging me!
What is the source of the "Main Sequence Data" table that contains the stellar class, radius, luminosity, and temperature? I've never seen a table like that, and it's very useful for figuring out what specific stars are like. Does it come from the Encyclopedia of Astronomy and Astrophysics?
Raddick 17:50, 25 July 2007 (UTC)
Hi Bob. The article on the main sequence is in need of fixing up. You have done such a great job on other astronomy pages, do you have time for that one? I can't spend much time on it, but am happy to pitch in or offer advice if needed. Timb66 10:21, 1 December 2007 (UTC)
Hi Bob. Many thanks for a great and thorough job. I haven't had time to read carefully yet, but my first impression is that some of this might be better in the main article on the Hertzsprung-Russell_diagram. What do you think? Timb66 ( talk) 05:34, 7 December 2007 (UTC)
The article basicly satisfies GA criteria. However there are some errors that should be fixed.
1) In the fourth paragraphs in 'History' there is a sentence "Russell proposed that the giant stars must have a lower density or higher surface-brightness than dwarfs". What does "higher surface brighteness" means. The brightnees is determened by the temperature, is not it? And the temperature is similar for both red dwarfs and red giants.
2) The last paragraph in the 'History' and the last paragraph in 'Characteristics' duplicate each other and should be merged. In addition the paragraph in 'Characteristics' lacks any citations.
3) Please, change bold font to the normal. I mean "zero age main sequence", or ZAMS in 'Formation' and main sequence in the caption of the last figure.
4) 'Cross-section of a Sun-like star, showing the different regions.'— there should be no period at the end of this caption.
5) In the 'Evolutionary tracks' there is a sentence "For intermediate-mass stars of more than 2 solar masses, the core can reach a temperature where it becomes hot enough to burn helium into carbon via the triple alpha process.". This implies that the Sun will never burn helium, which is wrong. The lower limit for the stars to burn helium is around 0.65 solar masses, which is enough to form a helium core of 0.45 solar masses.
6) The second paragraph from the end in 'Lifetime' is unreferenced.
7) The Vega may be a bad example of A0 star (in the table). It looks hot only because we look at its pole. It real mass is 2.1 solar masses, which is similar to β Pictoris. Its average spectral class is probably A3-A4 and luminosity is 37 solar (remember Vega article).
Ruslik ( talk) 19:31, 7 January 2008 (UTC)
I will promote the article, but 0.5 solar masses value is an underestimate. They seem to forget about large mass loss during RGB phase. I think this point deserves further research. Ruslik ( talk) 17:54, 8 January 2008 (UTC)
The Main sequence and the Luminosity articles give contradictory information about luminosity being proportional to a power of stelar mass. The Main Sequence article mentions M^3.5 while the luminosity article mentions M^3.9. Could someone correct this? -Paul- ( talk) 01:28, 9 February 2008 (UTC)
This is a new one to me. Can someone explain the difference between a main-sequence 'a' and main-sequence 'b' star? The classification system gets finer and finer! Is the Sun a G2Va or G2Vb star? 68Kustom ( talk) 10:21, 10 February 2008 (UTC)
What do people feel about a new section discussing the approximate power law relationships on the Main Sequence, and how they are derived? Luminosity-temp, Temp-Mass, Luminosity-Mass, and Stellar lifetime-Mass relationships could all be included for low, medium, and high mass main sequence stars. Density, radius, and other variables may also be included in their own scalings if wanted.... I'm not an expert so I wouldn't feel comfortable writing it up accurately, although if someone has the requisite background, I think it could be very useful.... —Preceding unsigned comment added by Firth m ( talk • contribs) 17:23, 28 February 2008 (UTC)
Don't have time to write these but... Need to
1) Effect of age and composition on stars - in particular the fact that population I stars have different MS curves than population III stars, and
2) The role of Main sequence in cosmic distance ladder.
Roadrunner ( talk) 05:18, 31 March 2009 (UTC)
What I came to this page looking for is some clue of how an individual star transits the HR diagram over the course of it's lifetime. I.E. consider a star that is at point (x,y) on the HR diagram during the main part of its lifetime, and then as the article states...
"At this point the star is evolving off the main sequence and entering the giant branch"
What will that star's giant point (x',y') be? The answers could go here or in the Stellar Evolution page. There's a diagram at the Stellar Evolution page, but it's kinda childishly conceptual. I'd be especially happy to see a curve that looks like a Carnot diagram - except non-adiabatic of course!
--
MathInclined (
talk)
02:27, 13 June 2011 (UTC)
In the "Formation" section it says "On the HR diagram, the evolving star moves up and to the right of the main sequence" but anything moving up the chart moves to the left , not the right. Johnor ( talk) 00:02, 1 April 2009 (UTC)
I'm moving this completely unsourced material here until it can be brought in line with FA criteria.
Sorry.— RJH ( talk) 22:51, 4 April 2009 (UTC)
Hi Folks,
I intend to create the Main Sequence article in the Simple English Wikipedia. (Think of the SEWP as an online students' or childrens' encyclopedia.) To do so, I have some questions. Please bear in mind that I'm a layman when it comes to astronomy.
As we say in SEWP, "You shouldn't lie to children". Children will accept whatever's in books as if it were gospel, especially for An Encyclopedia. Grown-ups know that when a reference book says A is B you have to treat that statement with a grain of salt (unless the article happens to be on mathematics, law or computer programming :-); children do not. Everything you say to them is either black or white. Therefore, we must be careful in our articles to be exact: to say what is true and, when adults do not know the truth precisely, to say that as well.
I could sprinkle my article with a lot of "Scientists say that..." and "according to most professional astrononers, ..." but that's weaseling. I prefer to say something like, for example, "About nine out of ten (or 999 out of 1000 or whatever) stars in the Milky Way were formed on the main sequence from protostars. (Of course, when we say 'on the main sequence' we really mean: having a brightness and a temperature that causes them to be plotted within the main sequence region on a Hertzsprung-Russell diagram.)"
I know my questions may seem babyish to you but I like to get my facts straight before I write about them in SEWP. Also, I would appreciate it if someone could look at the Simple English article Hertzsprung-Russell Diagram. Any comments are welcome.
Thanks a lot. -- RoyGoldsmith ( talk) 11:16, 11 August 2009 (UTC)
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
What part of the star do the temperatures in this table refer to? Surface? Core? Could someone with the appropriate knowledge alter this for clarity? QmunkE 15:47, 10 March 2006 (UTC)
I had a thought the other day. And tried to find this answer to this on Wikipedia and other sources. But as a complete layman became very confused, parsecs/light years ect. This is my thought, we (the human race) have been sending out RF signals of a reasonable strength since 1922, please correct me on this if I have this wrong. Based on this knowledge, I wondered how far and how many star like suns (G class stars) have these RF signals reached by this year, 2007 ? You know where I'm going with this thought, and yes maybe life is not restricted to G class stars, or maybe it is, or maybe only to G2V, and we all known G2V's are capable! Then there's the age of these stars, and then the metallic make up as well. I wish someone with the right knowledge would draw up a list of theses stars. And using the above knowledge. We could then break the list up into the most lightly to the most unlikely places that intelligent life may exist. And that have also received RF signals from us. I believe this list would be helpful to SETI, to reduce their listing down to size, so they can focus on a more broader range of RF signals. As I also believe the RF's they are searching are far too narrow, and I feel a lot of time and money is going to waist at SETI. If anyone can help me with this please do, maybe I've got this wrong as I'm just a layman. But in any case, post me something, its bugging me!
What is the source of the "Main Sequence Data" table that contains the stellar class, radius, luminosity, and temperature? I've never seen a table like that, and it's very useful for figuring out what specific stars are like. Does it come from the Encyclopedia of Astronomy and Astrophysics?
Raddick 17:50, 25 July 2007 (UTC)
Hi Bob. The article on the main sequence is in need of fixing up. You have done such a great job on other astronomy pages, do you have time for that one? I can't spend much time on it, but am happy to pitch in or offer advice if needed. Timb66 10:21, 1 December 2007 (UTC)
Hi Bob. Many thanks for a great and thorough job. I haven't had time to read carefully yet, but my first impression is that some of this might be better in the main article on the Hertzsprung-Russell_diagram. What do you think? Timb66 ( talk) 05:34, 7 December 2007 (UTC)
The article basicly satisfies GA criteria. However there are some errors that should be fixed.
1) In the fourth paragraphs in 'History' there is a sentence "Russell proposed that the giant stars must have a lower density or higher surface-brightness than dwarfs". What does "higher surface brighteness" means. The brightnees is determened by the temperature, is not it? And the temperature is similar for both red dwarfs and red giants.
2) The last paragraph in the 'History' and the last paragraph in 'Characteristics' duplicate each other and should be merged. In addition the paragraph in 'Characteristics' lacks any citations.
3) Please, change bold font to the normal. I mean "zero age main sequence", or ZAMS in 'Formation' and main sequence in the caption of the last figure.
4) 'Cross-section of a Sun-like star, showing the different regions.'— there should be no period at the end of this caption.
5) In the 'Evolutionary tracks' there is a sentence "For intermediate-mass stars of more than 2 solar masses, the core can reach a temperature where it becomes hot enough to burn helium into carbon via the triple alpha process.". This implies that the Sun will never burn helium, which is wrong. The lower limit for the stars to burn helium is around 0.65 solar masses, which is enough to form a helium core of 0.45 solar masses.
6) The second paragraph from the end in 'Lifetime' is unreferenced.
7) The Vega may be a bad example of A0 star (in the table). It looks hot only because we look at its pole. It real mass is 2.1 solar masses, which is similar to β Pictoris. Its average spectral class is probably A3-A4 and luminosity is 37 solar (remember Vega article).
Ruslik ( talk) 19:31, 7 January 2008 (UTC)
I will promote the article, but 0.5 solar masses value is an underestimate. They seem to forget about large mass loss during RGB phase. I think this point deserves further research. Ruslik ( talk) 17:54, 8 January 2008 (UTC)
The Main sequence and the Luminosity articles give contradictory information about luminosity being proportional to a power of stelar mass. The Main Sequence article mentions M^3.5 while the luminosity article mentions M^3.9. Could someone correct this? -Paul- ( talk) 01:28, 9 February 2008 (UTC)
This is a new one to me. Can someone explain the difference between a main-sequence 'a' and main-sequence 'b' star? The classification system gets finer and finer! Is the Sun a G2Va or G2Vb star? 68Kustom ( talk) 10:21, 10 February 2008 (UTC)
What do people feel about a new section discussing the approximate power law relationships on the Main Sequence, and how they are derived? Luminosity-temp, Temp-Mass, Luminosity-Mass, and Stellar lifetime-Mass relationships could all be included for low, medium, and high mass main sequence stars. Density, radius, and other variables may also be included in their own scalings if wanted.... I'm not an expert so I wouldn't feel comfortable writing it up accurately, although if someone has the requisite background, I think it could be very useful.... —Preceding unsigned comment added by Firth m ( talk • contribs) 17:23, 28 February 2008 (UTC)
Don't have time to write these but... Need to
1) Effect of age and composition on stars - in particular the fact that population I stars have different MS curves than population III stars, and
2) The role of Main sequence in cosmic distance ladder.
Roadrunner ( talk) 05:18, 31 March 2009 (UTC)
What I came to this page looking for is some clue of how an individual star transits the HR diagram over the course of it's lifetime. I.E. consider a star that is at point (x,y) on the HR diagram during the main part of its lifetime, and then as the article states...
"At this point the star is evolving off the main sequence and entering the giant branch"
What will that star's giant point (x',y') be? The answers could go here or in the Stellar Evolution page. There's a diagram at the Stellar Evolution page, but it's kinda childishly conceptual. I'd be especially happy to see a curve that looks like a Carnot diagram - except non-adiabatic of course!
--
MathInclined (
talk)
02:27, 13 June 2011 (UTC)
In the "Formation" section it says "On the HR diagram, the evolving star moves up and to the right of the main sequence" but anything moving up the chart moves to the left , not the right. Johnor ( talk) 00:02, 1 April 2009 (UTC)
I'm moving this completely unsourced material here until it can be brought in line with FA criteria.
Sorry.— RJH ( talk) 22:51, 4 April 2009 (UTC)
Hi Folks,
I intend to create the Main Sequence article in the Simple English Wikipedia. (Think of the SEWP as an online students' or childrens' encyclopedia.) To do so, I have some questions. Please bear in mind that I'm a layman when it comes to astronomy.
As we say in SEWP, "You shouldn't lie to children". Children will accept whatever's in books as if it were gospel, especially for An Encyclopedia. Grown-ups know that when a reference book says A is B you have to treat that statement with a grain of salt (unless the article happens to be on mathematics, law or computer programming :-); children do not. Everything you say to them is either black or white. Therefore, we must be careful in our articles to be exact: to say what is true and, when adults do not know the truth precisely, to say that as well.
I could sprinkle my article with a lot of "Scientists say that..." and "according to most professional astrononers, ..." but that's weaseling. I prefer to say something like, for example, "About nine out of ten (or 999 out of 1000 or whatever) stars in the Milky Way were formed on the main sequence from protostars. (Of course, when we say 'on the main sequence' we really mean: having a brightness and a temperature that causes them to be plotted within the main sequence region on a Hertzsprung-Russell diagram.)"
I know my questions may seem babyish to you but I like to get my facts straight before I write about them in SEWP. Also, I would appreciate it if someone could look at the Simple English article Hertzsprung-Russell Diagram. Any comments are welcome.
Thanks a lot. -- RoyGoldsmith ( talk) 11:16, 11 August 2009 (UTC)