2009 YE7: New "large" dwarf planet candidate discovered

[h2ouniverse]

A new dwarf planet candidate has been announced by Dr Rabinowitz, 2009 YE7, with an absolute magnitude of H=2.8. It lies in the Kuiper Belt (perihelion 35.9 AU, aphelion 51.1 AU). H2.8 would give it the tenth brightest absolute magnitude in the transneptunian region, after Eris (-1.2), Pluto (-0.7), Makemake (-0.3), Haumea (+0.2), Charon (+1), Sedna (+1.6), 2007 OR10 (+1.9), Orcus (+2.3) and Quaoar (+2.7).

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009+YE7&orb=1

We may expect revisions of H and other parameters in weeks to come (as often).

 

[pberrett]

That's great news

I wonder whether it could potentially be bigger than Eris, or alternatively whether a planet as big as earth is ever likely to be found out there somewhere.

If such a planet was found, partiuclarly if it had an atmosphere, it could really rekindle interest in Space exploration.

cheers Peter

 

[neilsox]

Typically planets with a thick or medium atmosphere are brighter than planets that have no atmosphere, but I suppose an exception is possible. Twice the radius means 4 times as bright, so I suppose an Earth mass planet is possible about twice as far from the Sun. Unless it produced more internal heat than Mercury, Venus, Earth and Mars combined, the atmosphere, except helium and hydrogen would be frozen. Neil

 

[MeteorWayne]

We may expect revisions of H and other parameters in weeks to come (as often).

Indeed, all the parameters should be considered very preliminary as there are only 8 observations over a 5 day interval (Dec 12-17).

It could even turn out to be a Plutino. The currently listed period is 287 years, but with such a short arc, it could easily turn out to be close to the 2:3 resonance with Neptune of 247 years that defines the class.

Thanx for the heads up!

 

[MeteorWayne]

That's great news

I wonder whether it could potentially be bigger than Eris, or alternatively whether a planet as big as earth is ever likely to be found out there somewhere.

If such a planet was found, partiuclarly if it had an atmosphere, it could really rekindle interest in Space exploration.

cheers Peter

It seems unlikely it's bigger than Eris, that's a pretty big gap in H value; but like I said, the data is preliminary; now that it's been announced there will be plenty of follow up observations.

 

[bjorkstrand]

Here's the data sheet so for this object. The arc is only 5 days.
Maybe they'll name it.

Jim


JPL/HORIZONS (2009 YE7) 2009-Dec-26 08:49:18
Rec #:648551 Soln.date: - # obs: 8 (5 days)

FK5/J2000.0 helio. eclip. TWO-BODY elements (AU, DAYS, DEG, period=Julian yrs):

EPOCH= 2455180.5 ! 2009-Dec-15.00 (CT) RMSW= n.a.
EC= .1748288 QR= 35.9205981 TP= 2507419.3027951
OM= 138.81889 W= 96.11184 IN= 29.22239
A= 43.5310856 MA= 180.73419 ADIST= 51.1415731
PER= 287.21522 N= .003431665 ANGMOM= .111748194
DAN= 43.00097 DDN= 41.42939 L= 235.8137317
B= 29.0403728 TP= 2152-Dec-23.8027951

Physical parameters (KM, SEC, rotational period in hours):
GM= n.a. RAD= n.a. ROTPER= n.a.
H= 2.8 G= .150 B-V= n.a.
ALBEDO= n.a. STYP= n.a.

ASTEROID comments:
1: soln ref.= E2009Y48, TWO_BODY OCC=E
2: source=MPC:mp1; MPC Cubewano

 

[bjorkstrand]

2009 YE7 2009 12 17 809 D. L. Rabinowitz

It was discovered on 17 Dec 2009 at La Silla Observatory(European Southern Observatory)(809).
Source = tnos list
I haven't seen an mpec for it. Anybody seen it?

Jim

 

[MeteorWayne]

The JPL entry appears to refernce this one:

http://www.cfa.harvard.edu/mpec/K09/K09Y48.html

 

[h2ouniverse]

Thanks all for the info

I'm surprised it has been spotted at La Silla. I did not know that they were doing sky surveys right now in La Silla. They use the largest telescopes for focused research not surveys. May be with a smaller one?

To MeteorWayne:
Indeed last time for 2007OR10, they had announced it at H=2.5 then revised few days later at H=1.9.
For the period, 287 years is very close to 7:4 so can be in the main resonances vs Neptune.

As far as diameter is concerned, I agree there is not a single chance that it can be bigger than Eris. For that to occur you would need a big misestimate of H combined with an ultra-low albedo. But the orbit of 2009 YE7 ("Yes, Evan") is significantly elliptical which tends to be associated to larger albedos (cycling of evaporation/recondensation of volatiles). If H is about 2.8, the diameter is probably comparable to the ones of Orcus and 2002 AW197 (which has a similar orbit) i.e. in the 700-1000km range. The 1100 km threshold that would theoretically allow for a deep subsurface ocean (Desch et al 2007) is unfortunately unlikely to be reached. We should be cautious though since there is so much variety in TNOs, we might have surprises...

 

[MeteorWayne]

And also, there are only 8 obs from one location (based on what you say). There could be large changes in H, as well as all orbital parameters including period, q, Q, a, etc.

If I can ask, where did you find out the source of the observations? I haven't found that in the places I usually check. However, the ones I use most of the time are more aimed at NEOs rather than TNOs

thanx, MW

 

[MeteorWayne]

Out of curiousity, I ran the JPL Horizon Ephemeris generator to find out where the object was and how bright.

It is currently located in the constellation Eridinus (below and to the right of Orion in the northen hemisphere). Current location ~ RA 4:00, Dec -9.5 degrees. The current observed magnitude is ~ +20, so it is quite faint, needing a big scope. It's highest in the sky around 9:30 PM local time, so probably out of reach for the Australian observatories. With the Full Moon passing nearby during the next week, I suspect there won't be any new observations until early next year.

This warning was posted with the Horizons ephemeris, never seen this before. It underscores the fact that the orbit is VERY poorly known at this time, and there could be significant changes when new obs come in after the Full Moon passes by.

** WARNING **

The initial state available for this object was a Keplerian two-body
orbital element set, not osculating elements. This means the orbit is probably
very poorly determined. Predictions for times many months or years from the
epoch may not be suitable for high-accuracy applications or expectations.

Since the epoch is inside or within ~30 days of the relatively short data
arc, the elements (such as they are) were numerically propagated with
perturbations, just as if they were osculating elements.

 

[bjorkstrand]

Here's a link to a harvard tno list which gives the observatory code.

http://www.cfa.harvard.edu/iau/lists/TNOs.html

ps SInce we lost the services of Michael Brown there will few discoveries.
2009 YE7 is a chance miracle.

Jim

 

[alan714586]

The current elements a=43.5 i=29 are similar to those of Haumea. If they are accurate it could be part of the collisional group associated with Haumea.

 

[h2ouniverse]

The current observed magnitude is ~ +20, so it is quite faint, needing a big scope. .[/color]

20 is quite "bright" actually. We reach 20 with our 400mm telescope. (and long exposures!)

 

[h2ouniverse]

2009 YE7 2009 12 17 809 D. L. Rabinowitz

It was discovered on 17 Dec 2009 at La Silla Observatory(European Southern Observatory)(809).
Source = tnos list

Jim

Rabinowicz has announced too two centaurs 2009 YD7 and YF7, located too at 4h RA, -10° and +1° elevation (2009 YE9 is at 4hRA, -9° elevation). That seems to indicate an observation campaign relatively restricted, as opposed to a large survey.

 

[MeteorWayne]

Here's a link to a harvard tno list which gives the observatory code.

http://www.cfa.harvard.edu/iau/lists/TNOs.html

ps SInce we lost the services of Michael Brown there will few discoveries.
2009 YE7 is a chance miracle.

Jim

Thanx for the link.

Hadn't heard about Michel Brown. Wassup with him? I guess I should peek at his blog.

 

[kg]

...The current observed magnitude is ~ +20, so it is quite faint, needing a big scope...

Is this object bright enough to show up in any archival survey images?

 

[MeteorWayne]

That's certainly a possibility.

In fact, it's one of the benefits of publishing the discovery. The brightness doesn't change, it's always around Mag +20, and with such a long orbital period, it moves very slowly, about 1 degree per year, so has been in Eridinus for decades in the past and for decades in the future. So now a search of old images can begin. In fact. with so much data online nowadays, I might do a search through images myself, if I have the time.

 

[bjorkstrand]

Survey Archives. Where are they?
I think there was an electronic one made around 2002.They scanned the 1950's photos. and in the 1980's.
Did you know that the germans had pluto on a 1914 photo. The first image.

Jim

 

[MeteorWayne]

Still searching, when I have time. I'm cooking dinner now

 

[h2ouniverse]

The current elements a=43.5 i=29 are similar to those of Haumea. If they are accurate it could be part of the collisional group associated with Haumea.

hi alan,

Looks indeed similar in terms of orbital plane. Would be bad news though (imnsho) for if YE7 is a haumeid, then a quite large albedo should be expected, wiping out any residual hope of a diameter larger than 1100km. Its physical characteristics would then be close to the ones of 2002 TX300.

Best regards.

 

[h2ouniverse]

2009 YE7: "not so large?" dwarf planet candidate discovered

Bad news, Mike Brown expects 2009 YE7 to be a Haumeid, hence with a ultra-high albedo.

http://www.mikebrownsplanets.com/2009/1 ... -past.html

Would then mean a very small diameter not even above 500. Dynamicists would be elated as they would get another tracker of a collision and orbital evolution of debris. But planetary scientists would miss a potential new planetary body.

Let's see when they get a spectrum.

 

[MeteorWayne]

Just to document, preliminary orbit based on 8 obs over 5 days:

Element Value Uncertainty Units
e 0.1748288
a 43.5310856 AU
q 35.9205981 AU
i 29.22239 deg
node 138.81889 deg
peri 96.11184 deg
M 180.73419 deg
tp 2507419.3027951
(2152-Dec-23.80279511) JED
period 104905.4976309 days
287.22 yr
n 0.00343166deg/d
Q 51.1415731 AU

There are no 1 sigma errors listed because the orbit is too poorly defined.

 

[3488]

I've tried to find out, but as yet there are no spectra for 2009 YE7.

I agree Joel,

Dynamics suggest Haumid, but I strongly resist jumping to conclusions as to the physical nature of this body. If it is 'bright' in visible light, but dim in IR, than it is optically bright & cold, thus smaller than anticipated (Enceladus, Triton, Eris, Haumea, being good examples).

OTOH it could be darker, but warmer & larger, like Mercury, Callisto, Umbriel, etc. Until we get that all important spectra, we dunno. Also if this body has a moon, that will help pin down the mass, thus density too.

Andrew Brown.

 

[MeteorWayne]

Honestly, we just have to wait until the moon gets out of the way, and more observations can be made. Of course, should predisovery images be found, it would refine the orbit, but there almost certainly would be no prediscovery spectra.

In a few days, that area of the sky will be moon free and we might find out more.