brown dwarf question

[idlewild]

<p>&nbsp;</p><p>&nbsp; Are brown dwarfs ordinary matter or are brown dwarfs dark matter?&nbsp; Are they MACHO's? </p><p>&nbsp;</p> <div class="Discussion_UserSignature"> </div>

 

[weeman]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;&nbsp; Are brown dwarfs ordinary matter or are brown dwarfs dark matter?&nbsp; Are they MACHO's? &nbsp; <br />Posted by idlewild</DIV><br /><br />Ordinary matter. They are failed stars that do not have enough mass to maintain hydrogen-burning nuclear fusion (like our Sun). Think of them as protostars that never made it to a full-fledged star. A protostar is a star that is early in its formation before it is massive enough to sustain nuclear fusion (with current planetary formation theory). </p><p>Also, brown dwarfs are detectable through modern instruments, since they still give off some form of electromagnetic radiation. Dark matter, on the other hand, gives off no radiation, thus it is completely undetectable with our current means of exlporation. </p> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>

 

[Philotas]

Have we found any birth places for brown dwarves? Do they form in H II regions? <div class="Discussion_UserSignature"> </div>

 

[idlewild]

<p>&nbsp;&nbsp; Is a brown dwarf a MACHO?&nbsp; I have a book that says that brown dwarves are MACHO's.&nbsp; </p><p>If they are MACHO's then aren't they dark matter? </p><p>The book says that MACHO's are believed to account for a relatively small proportion of the unseen <u>dark</u> <u>matter</u> in a galaxy's halo. </p><p>I am very confused! </p> <div class="Discussion_UserSignature"> </div>

 

[baulten]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;&nbsp; Is a brown dwarf a MACHO?&nbsp; I have a book that says that brown dwarves are MACHO's.&nbsp; If they are MACHO's then aren't they dark matter? The book says that MACHO's are believed to account for a relatively small proportion of the unseen dark matter in a galaxy's halo. I am very confused! <br /> Posted by idlewild</DIV></p><p>MACHOs are "MAssive Compact Halo Objects".&nbsp; Typically very dim pieces of regular matter, such as brown dwarfs, white dwarfs, black holes, and interstellar dust.&nbsp; So, it's not really dark matter, at least not non-baryonic dark matter. </p>

 

[weeman]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>MACHOs are "MAssive Compact Halo Objects".&nbsp; Typically very dim pieces of regular matter, such as brown dwarfs, white dwarfs, black holes, and interstellar dust.&nbsp; So, it's not really dark matter, at least not non-baryonic dark matter. <br /> Posted by baulten</DIV></p><p>IMO, MACHOs are one of the many limits to our knowledge of the cosmos. They are masses in the universe who's presence we can detect, yet we have no definitive answer as to what they are exactly. Of course, like you've stated, they may not be any one thing, but rather a collection of different interstellar objects.&nbsp; </p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>