KBOs Orcus & Quaoar have moons.

[3488]

KBOs Orcus & Quaoar have moons.<br /><br />Seems like many KBOs will have moons.<br /><br />Not surprised with Orcus & Quaoar though, as they are both rather large (approx the size of Charon<br />or half of Pluto).<br /><br />To me Quaoar is more interesting due to it being covered in crystalline ice, <br />cryovolcanism??<br /><br />What will its newly found moon reveal?<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[venator_3000]

Perhaps the newly found moons will help astronomers determine the densities, and therefore possibly the compositions, of these interesting bodies.<br /><br />v3k <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

They most certaily will help.<br />Moons allow computation of mass. <br />I suspect the largest source of incertainty in density will be in the volume of the bodies as the size is poorly contstrained. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[3488]

Hopefully next month, the HST will obtain spectra. If we can ascertain what the <br />surface compositions are, than we will know the albedo. Because the heliocentric distances<br />are known as well as distance from Earth, it should be a simple procedure of visible brightness<br />verses distance. <br /><br />With that we should know what size we are dealing with. <br /><br />As MeteorWayne says, the densities, thus mass of the primaries will then be calculatable<br />owing to orbital periods of the moons involved. We are going to learn an awful lot from this.<br /><br />Remember what Dysnomia, the moon of Eris revealed. <br /><br />That Eris is 27% more massive than Pluto. That was information we could get no other way,<br />at present.<br /><br />We'll see what the newly found moons will reveal obut Orcus & Quaoar.<br /><br />I wonder if these moons are chips of the old block or were captured? The spectra <br />should help.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[CalliArcale]

I would think it would be difficult for such small bodies to capture moons of substantial size. They're awfully small themselves.<br /><br />Very VERY cool news, though! <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[3488]

Hi CalliArcale, I suspect that too.<br /><br />Hopefully we will get spectral data next month as the HST has been allocated for<br />observations of both.<br /><br />I suspect that they are chips of the old block so to speak.<br /><br />It is fantastic news, we are going to learn much from this.<br /><br />Quaoar itself is worthy of study & a New Horizons type mission, as are Eris, Sedna & 2003 EL61.<br /><br />A surface odf crystalline ice with frozen methane. To me Quaoar was cryovolcanically<br />active, in the geologically recent past, as the ice turns homogenous over time, not<br />to mention cratering damage, so I suspect Quaoar may not be as heavily cratered as might<br />be expected. To have a moon also, is another big plus point. <br /><br />Perhaps formed from ejected ice crystals from Quaoar's ice volcanoes? <br /><br />I find in Quaoar's case, an impact origin for it's moon harder to take, as surely the<br />impact would affect Quaoar's clean crystalline ice?<br /><br />With Orcus, it does seem an impact origin for its moon is more likely. Orcus appears <br />far more primitive than Quaoar.<br /><br />Shortly after the Pluto encounter, New Horizons passes 16 AU from Quaoar. Wonder if the<br />LORRI camera could observe Quaoar & its moon from that distance?<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[brellis]

hi Calli<br /><font color="yellow">I would think it would be difficult for such small bodies to capture moons of substantial size. They're awfully small themselves. </font><br /><br />Well, we have a N3AR™ to study for answers to that mystery - <img src="/images/icons/cool.gif" /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[3488]

Thanks borman.<br /><br />I just hope the sort of situation you have described can be observed by the HST next month.<br /><br />I agree that only the Quaoar facing side of said moon can be used as evidence for <br />sputtering & / or geysers on Quaoar itself.<br /><br />I have no details as to sizes & distances of the Orcus & Quaoar moons.<br /><br />What ever, this is a fascinating development.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[jmilsom]

Very interesting. Thanks for posting. <br /><br />(thinks to himself - arrrgggh I've got to finish this thesis so I can back into my interest in KBOs) <div class="Discussion_UserSignature"> </div>

 

[h2ouniverse]

Hi Andrew,<br /><br />The source from EKO newsletter:<br />http://www.boulder.swri.edu/ekonews/issues/past/n051/html/index.html<br /><br />"More binaries...lots more... <br />In IAUC 8811, 8814, 8815, and 8816, Noll et al. report satellites of five TNOs from HST observations: <br />(123509) 2000 WK183, separation = 0.080 arcsec, magnitude difference = 0.4 mag <br />2002 WC19, separation = 0.090 arcsec, magnitude difference = 2.5 mag <br />2002 GZ31, separation = 0.070 arcsec, magnitude difference = 1.0 mag <br />2004 PB108, separation = 0.172 arcsec, magnitude difference = 1.2 mag <br />(60621) 2000 FE8, separation = 0.044 arcsec, magnitude difference = 0.6 mag <br />In IAUC 8812, Brown and Suer report satellites of four TNOs from HST observations: <br />(50000) Quaoar, separation = 0.35 arcsec, magnitude difference = 5.6 mag <br />(55637) 2002 UX25, separation = 0.164 arcsec, magnitude difference = 2.5 mag <br />(90482) Orcus, separation = 0.25 arcsec, magnitude difference = 2.7 mag <br />2003 AZ84, separation = 0.22 arcsec, magnitude difference = 5.0 mag <br />"<br /><br />Note that the four last primaries are all candidates to dwarfplanethood.<br />Apparently the orbits are not studied, only one spot per moon. So you can only use the angular separation as a minimum distance.<br />From difference in magnitude they have inferred<br />(from Wikipedia!)<br />when assuming albedo similar to the primary:<br />< 100km for Quaoar's moon <br />about 220km for Orcus'moon <br /><br />Regards

 

[3488]

Thanks Joel,<br /><br />Good to see you back,<br /><br />The figures you posted for the Orcus & Quaoar moons are quite large.<br /><br />Primary KBOs 55637 2002 UX25 & 2003 AZ84, see what you mean, diameters of 681 KM & 686 KM <br />diameters respectively.<br /><br />Their moons respectively approx 70 KM & 205 KM across repectively. The one of 2003 AZ84 does seem<br />very large in relation to the primary.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

hi andrew<br /><br />in reply to<br />-----<br />The one of 2003 AZ84 does seem <br />very large in relation to the primary.<br />--------<br /><br />Huh? The mag difference is 5, that means a factor of 100 on surface at iso-albedo, i.e. a factor of 10 on diameter.<br /><br />For Orcus, the mag difference is 2.7, hence a factor of 3.5 on diameter. I get about 250km.<br /><br />Regards.