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Elenin Dwarf Star Warning
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<blockquote data-quote="StarLord" data-source="post: 46239" data-attributes="member: 44"><p>Dwarf Stars have how much mass? The closest is how many Light Years away? Having a celestial "object" the same size as Jupiter would cause how many changes to our Sol, it's planets, and all of those chunks of planet and asteroids in that belt???</p><p> </p><p><span style="font-size: 15px"><strong><span style="font-size: 17px"><strong><span style="color: black"><span style="color: #ffffff">""Distinguishing high-mass brown dwarfs from low-mass stars</span></span></strong></span></strong></span></p><p></p><p><span style="color: #ffffff"><strong><a href="http://en.wikipedia.org/wiki/Lithium" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">Lithium</span></span></a></strong>: <a href="http://en.wikipedia.org/wiki/Lithium" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">Lithium</span></span></a> is generally present in brown dwarfs and not in low-mass stars. Stars, which achieve the high temperature necessary for fusing hydrogen, rapidly deplete their lithium. This occurs by a collision of <a href="http://en.wikipedia.org/wiki/Lithium-7" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">Lithium-7</span></span></a> and a <a href="http://en.wikipedia.org/wiki/Proton" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">proton</span></span></a> producing two <a href="http://en.wikipedia.org/wiki/Helium-4" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">Helium-4</span></span></a> nuclei. The temperature necessary for this reaction is just below the temperature necessary for hydrogen fusion. Convection in low-mass stars ensures that lithium in the whole volume of the star is depleted. Therefore, the presence of the lithium <a href="http://en.wikipedia.org/wiki/Spectral_line" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">line</span></span></a> in a candidate brown dwarf's spectrum is a strong indicator that it is indeed substellar. The use of lithium to distinguish candidate brown dwarfs from low-mass stars is commonly referred to as the <strong>lithium test</strong>, and was pioneered by <a href="http://en.wikipedia.org/w/index.php?title=Rafael_Rebolo,_Eduardo_Martin_and_Antonio_Magazzu&action=edit&redlink=1" target="_blank"><span style="color: #ba0000"><span style="color: #ffffff">Rafael Rebolo, Eduardo Martin and Antonio Magazzu</span></span></a>.</span></p><ul> <li data-xf-list-type="ul"><span style="color: #ffffff">However, lithium is also seen in very young stars, which have not yet had enough time to burn it all. Heavier stars like our sun can retain lithium in their outer atmospheres, which never get hot enough for lithium depletion, but those are distinguishable from brown dwarfs by their size.</span></li> <li data-xf-list-type="ul"><span style="color: #ffffff">Contrariwise, brown dwarfs at the high end of their mass range can be hot enough to deplete their lithium when they are young. Dwarfs of mass greater than 65 Jupiter masses can burn off their lithium by the time they are half a billion years old[Kulkarni], thus this test is not perfect.</span></li> </ul><p><span style="color: #ffffff"><strong><a href="http://en.wikipedia.org/wiki/Methane" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">Methane</span></span></a></strong>: Unlike stars, older brown dwarfs are sometimes cool enough that over very long periods of time their atmospheres can gather observable quantities of <a href="http://en.wikipedia.org/wiki/Methane" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">methane</span></span></a>. Dwarfs confirmed in this fashion include <a href="http://en.wikipedia.org/wiki/Gliese_229B" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">Gliese 229B</span></span></a>.</span></p><p><span style="color: #ffffff"><strong>Luminosity</strong>: Main sequence stars cool, but eventually reach a minimum <a href="http://en.wikipedia.org/wiki/Luminosity" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">luminosity</span></span></a> which they can sustain through steady fusion. This varies from star to star, but is generally at least 0.01% the luminosity of our Sun. Brown dwarfs cool and darken steadily over their lifetimes: sufficiently old brown dwarfs will be too faint to be detectable.</span></p><p><span style="color: #ffffff"><strong>Iron rain</strong> as part of atmospheric convection processes is possible only with brown dwarfs, and not with small stars. The spectroscopy research into iron rain is still ongoing–and not all brown dwarfs will always have this atmospheric anomaly.</span></p><p><span style="font-size: 15px"><strong><span style="font-size: 17px"><strong><span style="color: black"><span style="color: #ffffff"><span style="font-size: 13px"><p style="text-align: right">[<a href="http://en.wikipedia.org/w/index.php?title=Brown_dwarf&action=edit&section=4" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">edit</span></span></a>]</p><p></span>Distinguishing low-mass brown dwarfs from high-mass planets</span></span></strong></span></strong></span></p><p></p><p><span style="color: #ffffff">A remarkable property of brown dwarfs is that they are all roughly the same radius as Jupiter. At the high end of their mass range (60–90 Jupiter masses), the volume of a brown dwarf is governed primarily by <a href="http://en.wikipedia.org/wiki/Degenerate_matter" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">electron degeneracy</span></span></a> pressure,<a href="http://en.wikipedia.org/wiki/Brown_dwarf#cite_note-1" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">[2]</span></span></a> as it is in white dwarfs; at the low end of the range (10 Jupiter masses), their volume is governed primarily by <a href="http://en.wikipedia.org/wiki/Coulomb_barrier" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">Coulomb pressure</span></span></a>, as it is in planets. The net result is that the radii of brown dwarfs vary by only 10–15% over the range of possible masses. This can make distinguishing them from planets difficult.</span></p><p><span style="color: #ffffff">In addition, many brown dwarfs undergo no fusion; those at the <a href="http://en.wikipedia.org/wiki/Sub-brown_dwarf" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">low end of the mass range</span></span></a> (under 13 Jupiter masses) are never hot enough to fuse even deuterium, and even those at the high end of the mass range (over 60 Jupiter masses) cool quickly enough that they no longer undergo fusion after a period of time on the order of 10 million years. However, there are ways to distinguish dwarfs from planets:</span></p><p><span style="color: #ffffff"><strong>Mass</strong>, if over 10 Jupiter masses, means a body is unlikely to be a planet.</span></p><p><span style="color: #ffffff"><strong>X-ray and infrared</strong> spectra are telltale signs. Some brown dwarfs emit <a href="http://en.wikipedia.org/wiki/X-ray" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">X-rays</span></span></a>; and all "warm" dwarfs continue to glow tellingly in the red and <a href="http://en.wikipedia.org/wiki/Infrared" target="_blank"><span style="color: #0645ad"><span style="color: #ffffff">infrared</span></span></a> spectra until they cool to planetlike temperatures (under 1000 K).""</span></p><p></p><p><strong><a href="http://en.wikipedia.org/wiki/Brown_dwarf" target="_blank">http://en.wikipedia.org/wiki/Brown_dwarf</a></strong></p></blockquote><p></p>
[QUOTE="StarLord, post: 46239, member: 44"] Dwarf Stars have how much mass? The closest is how many Light Years away? Having a celestial "object" the same size as Jupiter would cause how many changes to our Sol, it's planets, and all of those chunks of planet and asteroids in that belt??? [SIZE=4][B][SIZE=17px][B][COLOR=black][COLOR=#ffffff]""Distinguishing high-mass brown dwarfs from low-mass stars[/COLOR][/COLOR][/B][/SIZE][/B][/SIZE] [COLOR=#ffffff][B][URL='http://en.wikipedia.org/wiki/Lithium'][COLOR=#0645ad][COLOR=#ffffff]Lithium[/COLOR][/COLOR][/URL][/B]: [URL='http://en.wikipedia.org/wiki/Lithium'][COLOR=#0645ad][COLOR=#ffffff]Lithium[/COLOR][/COLOR][/URL] is generally present in brown dwarfs and not in low-mass stars. Stars, which achieve the high temperature necessary for fusing hydrogen, rapidly deplete their lithium. This occurs by a collision of [URL='http://en.wikipedia.org/wiki/Lithium-7'][COLOR=#0645ad][COLOR=#ffffff]Lithium-7[/COLOR][/COLOR][/URL] and a [URL='http://en.wikipedia.org/wiki/Proton'][COLOR=#0645ad][COLOR=#ffffff]proton[/COLOR][/COLOR][/URL] producing two [URL='http://en.wikipedia.org/wiki/Helium-4'][COLOR=#0645ad][COLOR=#ffffff]Helium-4[/COLOR][/COLOR][/URL] nuclei. The temperature necessary for this reaction is just below the temperature necessary for hydrogen fusion. Convection in low-mass stars ensures that lithium in the whole volume of the star is depleted. Therefore, the presence of the lithium [URL='http://en.wikipedia.org/wiki/Spectral_line'][COLOR=#0645ad][COLOR=#ffffff]line[/COLOR][/COLOR][/URL] in a candidate brown dwarf's spectrum is a strong indicator that it is indeed substellar. The use of lithium to distinguish candidate brown dwarfs from low-mass stars is commonly referred to as the [B]lithium test[/B], and was pioneered by [URL='http://en.wikipedia.org/w/index.php?title=Rafael_Rebolo,_Eduardo_Martin_and_Antonio_Magazzu&action=edit&redlink=1'][COLOR=#ba0000][COLOR=#ffffff]Rafael Rebolo, Eduardo Martin and Antonio Magazzu[/COLOR][/COLOR][/URL].[/COLOR] [LIST] [*][COLOR=#ffffff]However, lithium is also seen in very young stars, which have not yet had enough time to burn it all. Heavier stars like our sun can retain lithium in their outer atmospheres, which never get hot enough for lithium depletion, but those are distinguishable from brown dwarfs by their size.[/COLOR] [*][COLOR=#ffffff]Contrariwise, brown dwarfs at the high end of their mass range can be hot enough to deplete their lithium when they are young. Dwarfs of mass greater than 65 Jupiter masses can burn off their lithium by the time they are half a billion years old[Kulkarni], thus this test is not perfect.[/COLOR] [/LIST] [COLOR=#ffffff][B][URL='http://en.wikipedia.org/wiki/Methane'][COLOR=#0645ad][COLOR=#ffffff]Methane[/COLOR][/COLOR][/URL][/B]: Unlike stars, older brown dwarfs are sometimes cool enough that over very long periods of time their atmospheres can gather observable quantities of [URL='http://en.wikipedia.org/wiki/Methane'][COLOR=#0645ad][COLOR=#ffffff]methane[/COLOR][/COLOR][/URL]. Dwarfs confirmed in this fashion include [URL='http://en.wikipedia.org/wiki/Gliese_229B'][COLOR=#0645ad][COLOR=#ffffff]Gliese 229B[/COLOR][/COLOR][/URL].[/COLOR] [COLOR=#ffffff][B]Luminosity[/B]: Main sequence stars cool, but eventually reach a minimum [URL='http://en.wikipedia.org/wiki/Luminosity'][COLOR=#0645ad][COLOR=#ffffff]luminosity[/COLOR][/COLOR][/URL] which they can sustain through steady fusion. This varies from star to star, but is generally at least 0.01% the luminosity of our Sun. Brown dwarfs cool and darken steadily over their lifetimes: sufficiently old brown dwarfs will be too faint to be detectable.[/COLOR] [COLOR=#ffffff][B]Iron rain[/B] as part of atmospheric convection processes is possible only with brown dwarfs, and not with small stars. The spectroscopy research into iron rain is still ongoing–and not all brown dwarfs will always have this atmospheric anomaly.[/COLOR] [SIZE=4][B][SIZE=17px][B][COLOR=black][COLOR=#ffffff][SIZE=13px][RIGHT][[URL='http://en.wikipedia.org/w/index.php?title=Brown_dwarf&action=edit§ion=4'][COLOR=#0645ad][COLOR=#ffffff]edit[/COLOR][/COLOR][/URL]][/RIGHT][/SIZE]Distinguishing low-mass brown dwarfs from high-mass planets[/COLOR][/COLOR][/B][/SIZE][/B][/SIZE] [COLOR=#ffffff]A remarkable property of brown dwarfs is that they are all roughly the same radius as Jupiter. At the high end of their mass range (60–90 Jupiter masses), the volume of a brown dwarf is governed primarily by [URL='http://en.wikipedia.org/wiki/Degenerate_matter'][COLOR=#0645ad][COLOR=#ffffff]electron degeneracy[/COLOR][/COLOR][/URL] pressure,[URL='http://en.wikipedia.org/wiki/Brown_dwarf#cite_note-1'][COLOR=#0645ad][COLOR=#ffffff][2][/COLOR][/COLOR][/URL] as it is in white dwarfs; at the low end of the range (10 Jupiter masses), their volume is governed primarily by [URL='http://en.wikipedia.org/wiki/Coulomb_barrier'][COLOR=#0645ad][COLOR=#ffffff]Coulomb pressure[/COLOR][/COLOR][/URL], as it is in planets. The net result is that the radii of brown dwarfs vary by only 10–15% over the range of possible masses. This can make distinguishing them from planets difficult.[/COLOR] [COLOR=#ffffff]In addition, many brown dwarfs undergo no fusion; those at the [URL='http://en.wikipedia.org/wiki/Sub-brown_dwarf'][COLOR=#0645ad][COLOR=#ffffff]low end of the mass range[/COLOR][/COLOR][/URL] (under 13 Jupiter masses) are never hot enough to fuse even deuterium, and even those at the high end of the mass range (over 60 Jupiter masses) cool quickly enough that they no longer undergo fusion after a period of time on the order of 10 million years. However, there are ways to distinguish dwarfs from planets:[/COLOR] [COLOR=#ffffff][B]Mass[/B], if over 10 Jupiter masses, means a body is unlikely to be a planet.[/COLOR] [COLOR=#ffffff][B]X-ray and infrared[/B] spectra are telltale signs. Some brown dwarfs emit [URL='http://en.wikipedia.org/wiki/X-ray'][COLOR=#0645ad][COLOR=#ffffff]X-rays[/COLOR][/COLOR][/URL]; and all "warm" dwarfs continue to glow tellingly in the red and [URL='http://en.wikipedia.org/wiki/Infrared'][COLOR=#0645ad][COLOR=#ffffff]infrared[/COLOR][/COLOR][/URL] spectra until they cool to planetlike temperatures (under 1000 K).""[/COLOR] [B][URL]http://en.wikipedia.org/wiki/Brown_dwarf[/URL][/B] [/QUOTE]
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