The article was promoted 04:59, 11 May 2008.
I'm nominating this article for featured article because I believe it meets the FA criteria and it is on an important astronomical topic. The article has undergone a PR and is now a GA. Hopefully it is reasonably accessible to people who are unfamiliar with astronomy, but it is necessarily technical in scope. I'll try to address any issues that arise. Thank you.— RJH ( talk) 19:39, 27 April 2008 (UTC) reply
I hope my comments will be helpful. Ruslik ( talk) 08:52, 28 April 2008 (UTC) reply
In summary, a great choice of topic matter and something that should be on hte main page one day. I think it's nearly there though I do get a niggling feeling some of the middle bits are a bit dry and could be difficult to follow, yet I am unsure how or indeed if they can be written in plainer English without sacrificing meaning. I'll look over the midle again a bit later today. Cheers, Casliber ( talk · contribs) 03:33, 1 May 2008 (UTC) reply
Cygnus X-1 (abbreviated Cyg X-1) is a compact X-ray source in the constellation Cygnus. It is one of the first black hole candidates to be discovered and is amongst the most studied astronomical objects in its class. As the estimated mass of this object is 8.7 times the mass of the Sun it is sufficiently compact to be a black hole. The X-rays it produces are believed to be the result of matter being stripped from its binary companion, a blue supergiant variable star known as HDE 226868, as its gasses fall toward Cyg X-1 forming an accretion disk and are heated to millions of Kelvin (K) in the process.
This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 40 solar masses. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole. [1]
Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1974, with Professor Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case for a gravitational singularity in the system.
I believe this has all of the same information, with the exception of the history, in a more compact form. Details on any of the statements are well covered in the article body, and the specifics don't seem to be required. The history definitely isn't, and follows immediately after anyway. Maury ( talk) 21:17, 7 May 2008 (UTC) reply
Ok, simple enough:
Cygnus X-1 (abbreviated Cyg X-1) is a compact X-ray source in the constellation Cygnus. The X-rays it produces are believed to be the result of gasses being heated to millions of Kelvin (K) in an accretion disk around the object, consisting of stellar wind from its binary companion, a blue supergiant variable star known as HDE 226868. A pair of jets arranged perpendicular to the disk is ejecting part of the in-falling material into interstellar space. Estimates place mass of this object at 8.7 times the mass of the Sun and its size at 300 km or less, sufficiently dense to be a black hole. It is one of the first black hole candidates to be discovered and is amongst the most studied astronomical objects in its class.
This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 40 solar masses. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole. [1]
Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1974, with Professor Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case for a gravitational singularity in the system.
I believe that addresses the concerns noted above. The only other issue is that it "unclear that the X-rays are caused by the heated gas ", but this is the baseline assumption and has been for the 20 years that I've been following the story. The "minority report" is interesting, but is covered in sufficient detail in the body (ie, one sentence). BTW, if it is reasonable to state that the object is not "stripping" the gasses from the binary, the caption on the image needs to be changed to reflect this. Maury ( talk) 03:20, 8 May 2008 (UTC) reply
Perhaps the discussion of the lead could be moved to article talk? SandyGeorgia ( Talk) 19:01, 8 May 2008 (UTC) reply
Support: lead much improved. Maury ( talk) 19:39, 8 May 2008 (UTC) reply
Support. This is amazingly accessible to non-astronomy buffs like me. Minor issues:
Karanacs ( talk) 15:36, 9 May 2008 (UTC) reply
The article was promoted 04:59, 11 May 2008.
I'm nominating this article for featured article because I believe it meets the FA criteria and it is on an important astronomical topic. The article has undergone a PR and is now a GA. Hopefully it is reasonably accessible to people who are unfamiliar with astronomy, but it is necessarily technical in scope. I'll try to address any issues that arise. Thank you.— RJH ( talk) 19:39, 27 April 2008 (UTC) reply
I hope my comments will be helpful. Ruslik ( talk) 08:52, 28 April 2008 (UTC) reply
In summary, a great choice of topic matter and something that should be on hte main page one day. I think it's nearly there though I do get a niggling feeling some of the middle bits are a bit dry and could be difficult to follow, yet I am unsure how or indeed if they can be written in plainer English without sacrificing meaning. I'll look over the midle again a bit later today. Cheers, Casliber ( talk · contribs) 03:33, 1 May 2008 (UTC) reply
Cygnus X-1 (abbreviated Cyg X-1) is a compact X-ray source in the constellation Cygnus. It is one of the first black hole candidates to be discovered and is amongst the most studied astronomical objects in its class. As the estimated mass of this object is 8.7 times the mass of the Sun it is sufficiently compact to be a black hole. The X-rays it produces are believed to be the result of matter being stripped from its binary companion, a blue supergiant variable star known as HDE 226868, as its gasses fall toward Cyg X-1 forming an accretion disk and are heated to millions of Kelvin (K) in the process.
This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 40 solar masses. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole. [1]
Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1974, with Professor Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case for a gravitational singularity in the system.
I believe this has all of the same information, with the exception of the history, in a more compact form. Details on any of the statements are well covered in the article body, and the specifics don't seem to be required. The history definitely isn't, and follows immediately after anyway. Maury ( talk) 21:17, 7 May 2008 (UTC) reply
Ok, simple enough:
Cygnus X-1 (abbreviated Cyg X-1) is a compact X-ray source in the constellation Cygnus. The X-rays it produces are believed to be the result of gasses being heated to millions of Kelvin (K) in an accretion disk around the object, consisting of stellar wind from its binary companion, a blue supergiant variable star known as HDE 226868. A pair of jets arranged perpendicular to the disk is ejecting part of the in-falling material into interstellar space. Estimates place mass of this object at 8.7 times the mass of the Sun and its size at 300 km or less, sufficiently dense to be a black hole. It is one of the first black hole candidates to be discovered and is amongst the most studied astronomical objects in its class.
This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 40 solar masses. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole. [1]
Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1974, with Professor Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case for a gravitational singularity in the system.
I believe that addresses the concerns noted above. The only other issue is that it "unclear that the X-rays are caused by the heated gas ", but this is the baseline assumption and has been for the 20 years that I've been following the story. The "minority report" is interesting, but is covered in sufficient detail in the body (ie, one sentence). BTW, if it is reasonable to state that the object is not "stripping" the gasses from the binary, the caption on the image needs to be changed to reflect this. Maury ( talk) 03:20, 8 May 2008 (UTC) reply
Perhaps the discussion of the lead could be moved to article talk? SandyGeorgia ( Talk) 19:01, 8 May 2008 (UTC) reply
Support: lead much improved. Maury ( talk) 19:39, 8 May 2008 (UTC) reply
Support. This is amazingly accessible to non-astronomy buffs like me. Minor issues:
Karanacs ( talk) 15:36, 9 May 2008 (UTC) reply