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Nearby white dwarf found, ready to go supernova
Type Ia supernova forming within the galaxy. The white dwarf's companion
is now in the range of 0.7 to 1.3 solar masses, and it may have been much more massive before but lost much of its mass to the white dwarf. Yousuf Khan Science Centric | News | XMM-Newton uncovers a celestial Rosetta stone "Astronomers have been on the trail of this mysterious object since 1997, when they discovered that something was giving off X-rays near the bright star HD 49798. Now, thanks to XMM-Newton's superior sensitivity, the mysterious object has been tracked along its orbit. The observation has shown it to be a white dwarf, the dead heart of a star, shining X-rays into space." http://www.sciencecentric.com/news/a...-rosetta-stone The nature of the bright subdwarf HD 49798 and its X-ray pulsating companion "The subdwarf, which prob- ably has a mass between 0.7 − 1.3M⊙, is the descendant of a massive asymptotic giant branch star that lost its hydrogen-rich outer layers in a common-envelope event." http://74.125.113.132/search?q=cache...n t=firefox-a |
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Nearby white dwarf found, ready to go supernova
On Sep 6, 10:01*am, Yousuf Khan wrote:
Type Ia supernova forming within the galaxy. The white dwarf's companion is now in the range of 0.7 to 1.3 solar masses, and it may have been much more massive before but lost much of its mass to the white dwarf. * * * * Yousuf Khan Science Centric | News | XMM-Newton uncovers a celestial Rosetta stone "Astronomers have been on the trail of this mysterious object since 1997, when they discovered that something was giving off X-rays near the bright star HD 49798. Now, thanks to XMM-Newton's superior sensitivity, the mysterious object has been tracked along its orbit. The observation has shown it to be a white dwarf, the dead heart of a star, shining X-rays into space."http://www.sciencecentric.com/news/article.php?q=09090422-xmm-newton-... The nature of the bright subdwarf HD 49798 and its X-ray pulsating companion "The subdwarf, which prob- ably has a mass between 0.7 − 1.3M⊙, is the descendant of a massive asymptotic giant branch star that lost its hydrogen-rich outer layers in a common-envelope event."http://74.125.113.132/search?q=cache:C7yAyloGuroJ:www.phys.uu.nl/~pol... Anything less than 8 solar masses is not likely to become a full blown supernova, but instead just another pesky nova that could expand its molecular debris out to a dozen some odd light years radii. Sirius B was originally 8+9solar masses before becoming a red supergiant of 5+ solar masses, subsequently terminating its nova phase into becoming a 1+ white dwarf that's nicely sucking away at Sirius A on each and every near pass. At some point Sirius A+B could merge and become yet another nova, and possibly evolve into a binary white dwarf system, or into becoming a singular and somewhat larger white dwarf that'll supposedly remain stable for billions of years. The bad new is, Sirius is too close and only getting closer for our level of discomfort tolerance, whereas human life as we've known Eden/ Earth to support may not be as local nova immune as we'd care to think. Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet” |
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Nearby white dwarf found, ready to go supernova
On Sep 6, 9:46*am, BradGuth wrote:
On Sep 6, 10:01*am, Yousuf Khan wrote: Type Ia supernova forming within the galaxy. The white dwarf's companion is now in the range of 0.7 to 1.3 solar masses, and it may have been much more massive before but lost much of its mass to the white dwarf. * * * * Yousuf Khan Science Centric | News | XMM-Newton uncovers a celestial Rosetta stone "Astronomers have been on the trail of this mysterious object since 1997, when they discovered that something was giving off X-rays near the bright star HD 49798. Now, thanks to XMM-Newton's superior sensitivity, the mysterious object has been tracked along its orbit. The observation has shown it to be a white dwarf, the dead heart of a star, shining X-rays into space."http://www.sciencecentric.com/news/article.php?q=09090422-xmm-newton-... The nature of the bright subdwarf HD 49798 and its X-ray pulsating companion "The subdwarf, which prob- ably has a mass between 0.7 − 1.3M⊙, is the descendant of a massive asymptotic giant branch star that lost its hydrogen-rich outer layers in a common-envelope event."http://74.125.113.132/search?q=cache:C7yAyloGuroJ:www.phys.uu.nl/~pol... Anything less than 8 solar masses is not likely to become a full blown supernova, but instead just another pesky nova that could expand its molecular debris out to a dozen some odd light years radii. Sirius B was originally 8+9solar masses before becoming a red supergiant of 5+ solar masses, subsequently terminating its nova phase into becoming a 1+ white dwarf that's nicely sucking away at Sirius A on each and every near pass. *At some point Sirius A+B could merge and become yet another nova, and possibly evolve into a binary white dwarf system, or into becoming a singular and somewhat larger white dwarf that'll supposedly remain stable for billions of years. The bad new is, Sirius is too close and only getting closer for our level of discomfort tolerance, whereas human life as we've known Eden/ Earth to support may not be as local nova immune as we'd care to think. *Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”- Hide quoted text - - Show quoted text - Stars don't exchange matter except it is possible by their stellar winds. But this is insignifricant mass. Mitch Raemsch |
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Nearby white dwarf found, ready to go supernova
On Sep 6, 10:59*am, BURT wrote:
On Sep 6, 9:46*am, BradGuth wrote: On Sep 6, 10:01*am, Yousuf Khan wrote: Type Ia supernova forming within the galaxy. The white dwarf's companion is now in the range of 0.7 to 1.3 solar masses, and it may have been much more massive before but lost much of its mass to the white dwarf.. * * * * Yousuf Khan Science Centric | News | XMM-Newton uncovers a celestial Rosetta stone "Astronomers have been on the trail of this mysterious object since 1997, when they discovered that something was giving off X-rays near the bright star HD 49798. Now, thanks to XMM-Newton's superior sensitivity, the mysterious object has been tracked along its orbit. The observation has shown it to be a white dwarf, the dead heart of a star, shining X-rays into space."http://www.sciencecentric.com/news/article.php?q=09090422-xmm-newton-... The nature of the bright subdwarf HD 49798 and its X-ray pulsating companion "The subdwarf, which prob- ably has a mass between 0.7 − 1.3M⊙, is the descendant of a massive asymptotic giant branch star that lost its hydrogen-rich outer layers in a common-envelope event."http://74.125.113.132/search?q=cache:C7yAyloGuroJ:www.phys.uu.nl/~pol... Anything less than 8 solar masses is not likely to become a full blown supernova, but instead just another pesky nova that could expand its molecular debris out to a dozen some odd light years radii. Sirius B was originally 8+9solar masses before becoming a red supergiant of 5+ solar masses, subsequently terminating its nova phase into becoming a 1+ white dwarf that's nicely sucking away at Sirius A on each and every near pass. *At some point Sirius A+B could merge and become yet another nova, and possibly evolve into a binary white dwarf system, or into becoming a singular and somewhat larger white dwarf that'll supposedly remain stable for billions of years. The bad new is, Sirius is too close and only getting closer for our level of discomfort tolerance, whereas human life as we've known Eden/ Earth to support may not be as local nova immune as we'd care to think. *Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”- Hide quoted text - - Show quoted text - Stars don't exchange matter except it is possible by their stellar winds. But this is insignifricant mass. Mitch Raemsch But stars do merge (run into one another). Or doesn't trajectory and gravity count for anything? ~ BG |
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Nearby white dwarf found, ready to go supernova
BradGuth wrote:
On Sep 6, 10:01 am, Yousuf Khan wrote: Type Ia supernova forming within the galaxy. The white dwarf's companion is now in the range of 0.7 to 1.3 solar masses, and it may have been much more massive before but lost much of its mass to the white dwarf. Anything less than 8 solar masses is not likely to become a full blown supernova, but instead just another pesky nova that could expand its molecular debris out to a dozen some odd light years radii. Read it again, it's a white dwarf, so it doesn't need to be supermassive. It accretes mass off its companion and heads towards the Chandresekhar Limit. Yousuf Khan |
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Nearby white dwarf found, ready to go supernova
On Sep 6, 4:09*pm, Yousuf Khan wrote:
BradGuth wrote: On Sep 6, 10:01 am, Yousuf Khan wrote: Type Ia supernova forming within the galaxy. The white dwarf's companion is now in the range of 0.7 to 1.3 solar masses, and it may have been much more massive before but lost much of its mass to the white dwarf. Anything less than 8 solar masses is not likely to become a full blown supernova, but instead just another pesky nova that could expand its molecular debris out to a dozen some odd light years radii. Read it again, it's a white dwarf, so it doesn't need to be supermassive. It accretes mass off its companion and heads towards the Chandresekhar Limit. * * * * Yousuf Khan Exactly like Sirius-B, although Sirius-A is kind of a wussy star to draw from. ~ BG |
#7
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Nearby white dwarf found, ready to go supernova
On Sep 6, 2:20*pm, BradGuth wrote:
On Sep 6, 10:59*am, BURT wrote: On Sep 6, 9:46*am, BradGuth wrote: On Sep 6, 10:01*am, Yousuf Khan wrote: Type Ia supernova forming within the galaxy. The white dwarf's companion is now in the range of 0.7 to 1.3 solar masses, and it may have been much more massive before but lost much of its mass to the white dwarf. * * * * Yousuf Khan Science Centric | News | XMM-Newton uncovers a celestial Rosetta stone "Astronomers have been on the trail of this mysterious object since 1997, when they discovered that something was giving off X-rays near the bright star HD 49798. Now, thanks to XMM-Newton's superior sensitivity, the mysterious object has been tracked along its orbit. The observation has shown it to be a white dwarf, the dead heart of a star, shining X-rays into space."http://www.sciencecentric.com/news/article.php?q=09090422-xmm-newton-... The nature of the bright subdwarf HD 49798 and its X-ray pulsating companion "The subdwarf, which prob- ably has a mass between 0.7 − 1.3M⊙, is the descendant of a massive asymptotic giant branch star that lost its hydrogen-rich outer layers in a common-envelope event."http://74.125.113.132/search?q=cache:C7yAyloGuroJ:www.phys.uu.nl/~pol... Anything less than 8 solar masses is not likely to become a full blown supernova, but instead just another pesky nova that could expand its molecular debris out to a dozen some odd light years radii. Sirius B was originally 8+9solar masses before becoming a red supergiant of 5+ solar masses, subsequently terminating its nova phase into becoming a 1+ white dwarf that's nicely sucking away at Sirius A on each and every near pass. *At some point Sirius A+B could merge and become yet another nova, and possibly evolve into a binary white dwarf system, or into becoming a singular and somewhat larger white dwarf that'll supposedly remain stable for billions of years. The bad new is, Sirius is too close and only getting closer for our level of discomfort tolerance, whereas human life as we've known Eden/ Earth to support may not be as local nova immune as we'd care to think. *Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”- Hide quoted text - - Show quoted text - Stars don't exchange matter except it is possible by their stellar winds. But this is insignifricant mass. Mitch Raemsch But stars do merge (run into one another). *Or doesn't trajectory and gravity count for anything? *~ BG- Hide quoted text - - Show quoted text - No. Rarely. It has never been observed in astronomy. Gravity tends to keep stars in orbit not flying into one another. If that was true eventually all stars would collide. And that is simply not the case. Mitch Raemsch |
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Nearby white dwarf found, ready to go supernova
Yousuf Khan wrote:
[...] To be "ready to go" means that they have an understanding of the accretion rate and the existing stockpile of hydrogen on the star's surface. Their entire basis is knowing that the mass of the object [within 50%...laff] is that it is close to the Chandrasakhar limit, which has proben to be rather fungible. No accretion rate, no timeframe. |
#9
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Nearby white dwarf found, ready to go supernova
On Sep 6, 10:09*pm, eric gisse wrote:
To be "ready to go" means that they have an understanding of the accretion rate and the existing stockpile of hydrogen on the star's surface. Their entire basis is knowing that the mass of the object [within 50%...laff] is that it is close to the Chandrasakhar limit, which has proben to be rather fungible. No accretion rate, no timeframe. I don't know if they don't have an accretion rate or not, more likely it just wasn't mentioned in this article. Yousuf Khan |
#10
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Eric Gisse isn't subscribed to the “Sci.Astro” news·group.
Eric Gisse isn't subscribed to the “Sci.Astro” news·group; so, unless he Googles it, he won't see your reply, Yousuf Khan. He has me plonked, so he won't see this either. Eric's news·reader, knode, automatically adds the mono·group followup: Followup-To: sci.astro As a former Google·Groups user, Eric doesn't understand that he asked you to move to a news·group that he doesn't read. ························ For those just now tuning in, the heritage of this post is: ―― Oldest ancestor first ―― Yousuf•Khan eric•gisse Yousuf•Khan Sci.Astro Google·, ISO-8859-1, 70.49.137.78, Gecko➤Jun·2009➤XP, Sep 6, 2009 Nearby white dwarf found, ready to go supernova |
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