Comments on Mike Brown's Planets: A ghost of Christmas past

Kevin -- Yup. TX300 indeed has a high albedo. Funn...

2010-06-17T12:43:23.747-07:00

Kevin -- Yup. TX300 indeed has a high albedo. Funny to see the paper say "unexpectedly high." Clearly they don't read the blog here....

2002 TX300 is now estimated to be about ~286km in ...

2010-06-17T12:08:42.938-07:00

2002 TX300 is now estimated to be about ~286km in diameter with an albedo of ~0.88.

Size and albedo of Kuiper belt object 55636 from a stellar occultation: 10.1038/nature09109

-- Kevin Heider

To Mike, thanks for the answer! (in addition to p...

2010-01-07T12:42:21.500-08:00

To Mike,

thanks for the answer! (in addition to populating the Solar System!)
A typo: the Eris-orbit-like object announced by D. Rabinowicz is 2009 YG19, not QG19.

Neptune's Guard

IIRC, there are a few Plutinos with inclinations u...

2010-01-07T10:40:20.390-08:00

IIRC, there are a few Plutinos with inclinations up to 33 degrees. Still (as you said, and I have for a few days) even with a 24 day arc, it's too early to bet farms or houses on how the orbit will turn out :)

Meteor Wayne

NG: The distance is usually very well determined. ...

2010-01-07T10:03:36.789-08:00

NG: The distance is usually very well determined. It's usually the photometry that is bad. We (and I suspect D. Rabin, too) take uncalibrated images for our searching and only try to calibrate them after the fact. As you see, that doesn't always work so well. It's not too much of a problem, because when we DO find something, we always go back and take calibrated images of it. But those first reports can be a bit amiss. I must say, though, I've never seen one change by quite this much. My guess is that David is still working out the bugs in his southern hemisphere observing. As always, I would say, stay tuned.

Still bet it's part of the Haumea family, though. :)

Hi Mike, I am baffled by the H=4.1 too. Given tha...

2010-01-07T09:58:53.481-08:00

Hi Mike,

I am baffled by the H=4.1 too. Given that you are supposed to know your photometry and your distance to the Sun, how can H vary so much?
By the way you had a big variation too on 2007 OR10 going from 2.5 to 1.9 in the days after your announcement. At that time, I thought this was due to revision of distance to the Sun (outwards) by you but only you know the answer!
JPL.orbits still displays an object at about 50AU from the Earth so it seems indeed the distance has not been revised.
Guh?

Neptune's guard

Wow; you guys are right, 2009 YE7 is actually MUCH...

2010-01-07T09:45:20.551-08:00

Wow; you guys are right, 2009 YE7 is actually MUCH fainter than the initial report (something like the 26th brightest, not the 9th brightest). And a longer observation suggests that it is a Plutino, not part of the Haumea family.

Interestingly, though, with only a 24 day arc, you should not put any faith in semimajor axis or eccentricity, only in inclination and distance. With the inclination still at 29 degrees I am still willing to bet that this guy is part of the Haumea family. But the H=4.1 is the part that now gives me pause.

We need a color. Anyone measured one yet? When someone shows that it is not neutrally colored I will officially give up on my prediction!

Mike, you made on incorrect statement. It had not ...

2010-01-07T08:00:09.919-08:00

Mike, you made on incorrect statement. It had not been observed for a "few weeks", but rather only 5 days, IMHO, too early to assume much about the orbit. New data in today (11 obs over 24 day arc) has shortened the period considerably, now leading to MPC classifying it as a Plutino rather than a Cubewano.

MW

Neptune's guard to Mike Hi again Mike, Very bad ne...

2010-01-07T04:05:29.459-08:00

Neptune's guard to Mike
Hi again Mike,
Very bad news... 2009YE7 parameters have been revised at MPC, with H collapsing down to 4.1!!! Semi-major axis a would decrease to 39.7AU, that of a Plutino. Perihelion q of 26.5AU would be extremely low for a plutino...

So long for the haumeid assumption, unless this is the remnant of the impactor on the proto-Haumea?

By the way, D. Rabinowicz has announced another Eris-orbit-like object (2009 QG19, at H=6 and a=67.7AU).

From Neptune's guard: Mike, is 2007 OR10 ultra-red...

2010-01-06T00:19:07.626-08:00

From Neptune's guard:
Mike, is 2007 OR10 ultra-red AND ultra-bright (like Makemake) or just ultra-red? In other words, can we hope that the albedo is not too high for Snow White (or should I say Snow Red) to be above Desch's threshold of 1100km in diameter?

In any case this is indeed surprising that such a body with an Eris-like orbit presents a dissimilar surface spectrum, while being like Eris close to its aphelion (hence at the coldest end of its potential N2 recondensation cycle).
I like it: for this means a specificity hence more interest. 2006 QH181 is on a similar orbit with H=3.8, so hopefully not too dissimilar in size: may be its spectrum would provide for an interesting comparison?

By the way Mike, there seems to be many objects with an Eris-like period and eccentricity, close to the 10:3 resonance vs Neptune(but not at the resonance, apparently, most often with a>67.07=a(10:3)). Eris, 2007OR10, 2009 KN30, 2008 OG19, 2006 QH181, 2006 HX122, 2003 QK91, 2003 OS33, 2001 OM109, 2001 OT108, 2001 FN&FJ194, 2000 QK226... This is a significant fraction of all SDOs discovered to day. Looks like an attraction point period-wise. What is your opinion about it?

@kevin We just got new data on 2007 OR10, and, ind...

2010-01-05T21:35:59.888-08:00

@kevin We just got new data on 2007 OR10, and, indeed, it is crazy red. What does this mean? Current theory: baffled.

@chuck: age constraint on Haumea is actually quite a cool little gravitational story. we can basically simulate how long the chunks took to disperse. For [gory] details, see
http://www.gps.caltech.edu/~mbrown/papers
/ps/darin1.pdf

@greg: I really wanted to believe that theory about 8 years ago, but the rest of the dynamics of the Kuiper belt doesn't make sense. Doesn't mean there is nothing out there. I'm working [slowly] on a piece about the true limits to what might be found.

@NeptunesGuard: I'm with you. The bigger the better.

From Neptune's Guard Hi Mike, I can understand you...

2010-01-04T13:08:50.670-08:00

From Neptune's Guard
Hi Mike,
I can understand your joy to see another potential haumeid that would consolidate your models. However for those who await eagerly the discovery of new planetary bodies, with some structure and astrogeological value per se, this prospect is a disappointment. I hope that the southern skies will reveal bigger fishes.

Oh, by the way, you state that 2009YE7 comes 9th in absolute magnitude but I'm afraid you are forgetting Charon (H=+1).

Mike, if you could indulge an old Caltecher in wha...

2010-01-03T17:10:27.252-08:00

Mike, if you could indulge an old Caltecher in what might be a dumb question, is anyone thinking that things like the abrupt edge to the Kuiper Belt and the odd orbit of Sedna are caused by an unseen Brown Dwarf companion to the sun? It's one of the things that has me especially interested in the WISE mission, but I have never seen anyone voice this hypothesis, so I'm wondering if there's some obvious reason it can't be so.

--Greg

Wikipedia is also a time machine: Mike is right, H...

2010-01-02T01:41:40.749-08:00

Wikipedia is also a time machine: Mike is right, Haumea was "twice as wide as Pluto" back in July 2005. :-) Then the IAU used their ray gun to shrink everything.

In March 2004 Sedna was almost 2000 kilometers.

In February 2004 Orcus was assumed to be approximately 1600 km.

In October 2002 Quaoar was 1,280 kilometres.

-- Kevin Heider

Where does the age constraint on the Haumea breaku...

2009-12-30T03:26:21.923-08:00

Where does the age constraint on the Haumea breakup come from?

Idea for a new bumper sticker: Reunite Haumea! B...

2009-12-29T22:07:56.284-08:00

Idea for a new bumper sticker: Reunite Haumea!

Bob Shepard

Any updates on the red-sloped reflectance spectrum...

2009-12-29T21:26:15.068-08:00

Any updates on the red-sloped reflectance spectrum of 2007 OR10? I assume the redness is caused by tholins?

-- Kevin Heider

Kevin -- Oh yeah, 2002 TX300 >definitely< has an a...

2009-12-29T21:20:01.113-08:00

Kevin --
Oh yeah, 2002 TX300 >definitely< has an albedo of near 0.7. It's spectrum is identical to Haumea's and its satellites, so it would be pretty tough not to have the same surface thus same albedo. It is certainly in the 360 km range. I'm not quite prepared to say "definitely" for 2009 YE7, until we get a spectrum measured, but, as I said, I'll be happy to take bets! ;)
Mike

Mike; Thank you for bringing all of us up to spee...

2009-12-29T21:07:43.117-08:00

Mike;

Thank you for bringing all of us up to speed on the ideas behind objects like 2009 YE7. Haumeid or not, it is quite funny that it was discovered almost exactly 5 years after Santa was.

Since you are inclined to believe that YE7 (H=2.8) has a high albedo of 0.7 resulting in a diameter near 440km, do you think 2002 TX300 (H=3.2) has basically the same albedo and thus is even smaller (H=3.2 with albedo=0.7 would be 364km)? Is there any reason to think brighter/larger Haumeids could have an intermediate albedo of like 0.4?

-- Kevin Heider

Personally I think it's way too premature to say w...

2009-12-29T21:00:25.309-08:00

Personally I think it's way too premature to say we've given up on counting Kuiper Belt Objects as planets. That seems to depend on whether one takes a dynamical or geophysical perspective. I wonder if we may not end up with two different paradigms existing side by side depending on the perspective of the astronomer in question. Then there is also the theory of a brown dwarf somewhere possibly as far as the Oort Cloud. Would that be a second star, making our system a binary, a planet, a dwarf planet, or something else?

As an astronomy grad student, I have to say, you don't need to have a kid to be super excited to find out about a new Kuiper Belt Object, exoplanet, or any astronomical discovery. Sometimes it seems like the academic world shows favoritism towards PhDs and MScs with kids as opposed to those who don't have them. There is nothing better than a new discovery, period. Like you I've also heard that a couple of new Kuiper Belt searches are being started, so I'm looking forward to some great news in the New Year.

I understand that next year the newly launched WIS...

2009-12-29T16:19:40.193-08:00

I understand that next year the newly launched WISE telescope will scan the heavans looking for previously unseen objects.

I think we are in for some interesting discoveries!

One thing I have noted though.

Our solar system seems to be defined by a inner system of medium rocky planets then a middle system of large gas giants (getting progressively smaller) followed by an outer system of small rocky planets.

Following the pattern I wonder whether outside the outer system of small rocky bodies there is an outer outer system of small gas giants.

And then past that an outer, outer, outer system of small to medium rocky bodies etc...

Regards Peter

It is stuff like this is why science is so awesome...

2009-12-29T12:52:32.338-08:00

It is stuff like this is why science is so awesome. There is so much to learn, to explore and to think about. The Kuiper Belt still has big surprises out there. As a matter of fact, I made a bet with a Twitter follower of mine that someone (maybe you) will discover an object as large as Mercury in the next twenty years.

A also think there is a chance (maybe 25%) that the sun has a brown dwarf companion out there.

Thank for sharing your insights!