New data on 2005 YU 55

[MeteorWayne]

New observations have been made, extending the arc to over 4 years (1519 days from 12/24/2005 to 2/20/2010)

It has now two Torino Scale 1 impacts listed on Nov 10, 2103, PS for them are -1.90 and -2.48. Cumulative PS for the object is now -1.79, with 46 potential impacts between 2043 and 2109. (The period for TS ranking now extends to 2110)

The object is ~ 140 meters in diameter, and the weighted impact velocity is 17.56 km/sec with an energy of 130 Megatons.

 

[nimbus]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

I must be doing something wrong - the NASA Java applet doesn't show YU55 and the Earth near each other in Nov 2103.

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

The only thing you're doing wrong is failing to read the warning above the applet

"This applet is provided as a 3D orbit visualization tool. The applet was implemented using 2-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances. For accurate long-term ephemerides, please instead use our Horizons system.

Using the Ephemeris link at the bottom, I find a close approach of 0.111 AU on Nov 3-6 2103. With the large uncertainty associated with projections 93 years in the future, that is sufficient to explain the risk.

In fact this year's close approach (0.0152 AU, or 5.9 Lunar Distance on April 20) is far closer, but the uncertainty in it's position is far lower as well.

Oh, and do be careful to specify 2005 YU 55...there are YU 55's an many other years over the last decade.

 

[silylene]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

Wayne, interesting! What was the PS prior to the new observations?

 

[silylene]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

Slightly off topic, but 2010 CL 19 is turning out to be interesting too. 4 day arc. If the arc grows to 1 week, and it continues to be interesting, let's start a new thread.

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

Wayne, interesting! What was the PS prior to the new observations?

Yeah, of course I don't know off the top of my head. I am checking....somewhere in my notebook I listed the top 10 or 15 PS objects, but haven't found it yet

 

[nimbus]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

Thanks Wayne. I'd actually skimmed over that part in bold and couldn't understand why the Horizons page gave collision that didn't match the java simulation.

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

Just to clarify, the risk page is called Sentry, the Horizons info is the detailed orbits and Ephemeris's that come from calculating the effects of all the planets and the 3 largest asteroids (whcih account for > 95% of the mass affecting NEOs.) (the link near the bottom of the object page). Those perterbations are used in calculating the Sentry risk page, the Ephemeris gives accurate positional info on the object.

 

[galldora]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

I so *love* that I can pop by here when I have a little freak out :roll: (though I honestly do try not to, so don't laugh at me too much ) and then it's okay again. My silly admission for the day.

Thank you for providing the information. It is very much appreciated.

hehe now if this post included information for newbie budgie owners, it'd be ever more awesome :lol:

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

I wanted to add that the NEODyS analysis has a much lower impact risk for the Nov 10 2103 virtual impactors. The highest has a PS of -2.51 as compared to the Sentry highest PS of - 1.79.

The PS risk of the 13 impactors on that date (which also include 1 on the 11th) are

-2.51
-2.60
-3.01
-4.80
-5.60
-6.11
-6.39
-7.03
-7.14
-7.22
-7.43
-7.55
-7.58

Sentry has 6 impactors:

PS -1.90
-2.46
-4.17
-5.66
-6.21
-6.49

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

# obs. used (total) 46
data-arc span 1519 days (4.16 yr)
first obs. used 2005-12-24
last obs. used 2010-02-20
planetary ephem. DE405
SB-pert. ephem. SB405-CPV-2
quality code 3
fit RMS .77215
data source ORB
producer Otto Matic
solution date 2010-Feb-20 19:50:02


Additional Information Earth MOID = .00110242 AU
T_jup = 5.408

Element Value Uncertainty (1-sigma) Units
e .4289279337869014 ...1.7448e-05
a 1.140607402265598 ...2.2157e-06 AU
q .6513690259497699 ...2.1132e-05 AU
i .508101160809019 ......3.1558e-05 deg
node 39.43271510661236 ..0.00656 deg
peri 268.8880218964223 ..0.0062951 deg
M 224.2796711077019.. 0.0035485 deg
tp 2455368.243271220332
(2010-Jun-20.74327123) 0.0047429 JED
period 444.9412857468144....0.0012965 d
1.22 .....3.55e-06 yr

n .8090955178406423.... 2.3576e-06 deg/d
Q 1.629845778581426.... 3.1661e-06 AU

 

[silylene]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

new data! risk increases

2005 YU55 JPL Sentry 0513
collisions 2043-2109 number 61
cum probability 8.1e-04 (1 chance in 1234)
TS = -1.83 cum -2.00 total
PS = 1

JPL: "Analysis based on 51 observations spanning 1533.0 days (2005-Dec-24.29832 to 2010-Mar-06.342175)." Diameter approximately 0.140 km. from mean, weighted H=21.9.

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

New observations through March 18th. JPL Risk page has not been updated since March 10th, still showing highest impact risk 1 on 1230 on Nov 10 2103. Cumulative PS -1.83, Max PS -2.00.

Current Sentry page (Through Mar 10, 51 obs/1533 days) has 9 virtual impactors on that date ranging from PS -2.00 and -2.38 through - 6.78.

NEODyS (66 obs/1545 days) has 15 VI's on that date from PS -2.56 to -7.82.

New NEODyS orbital parameters:

Value ....1-σ variation Units
a =1.14061 ...1.975e-06 AU
e =0.428923 ....1.311e-05
i =0.508 ....1.426e-05 deg
Ω =39.429.... 0.001939 deg
ω =268.892 ....0.001972 deg
M= 224.279 ....0.001108 deg

While JPL risk page has not updated, their sbdb page has:

Orbit Determination Parameters # obs. used (total) 66
data-arc span 1545 days (4.23 yr)
first obs. used 2005-12-24
last obs. used 2010-03-18
planetary ephem. DE405
SB-pert. ephem. SB405-CPV-2
quality code 3
fit RMS .69855
data source ORB
producer Otto Matic
solution date 2010-Mar-19 01:50:13


Additional Information Earth MOID = .001103 AU
T_jup = 5.408

Element Value.... Uncertainty (1-sigma) Units
e .4289258245544528.... 1.263e-05
a 1.140607635720558.... 1.9007e-06 AU
q .6513715650760128 ....1.5487e-05 AU
i .5080799291477561...... 1.3807e-05 deg
node 39.42845786625636.. 0.0018875 deg
peri 268.8924463172157 ...0.0019177 deg
M 224.2792059529726 .....0.0010718 deg
tp 2455368.243897627109
(2010-Jun-20.74389763) 0.0017036 JED
period 444.941422350025...0.0011122 d
1.22... 3.045e-06 yr
n .809095269437055 ....2.0224e-06 deg/d
Q 1.629843706365103 ....2.716e-06 AU

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

Some new updates. The JPL Sentry risk page has been updated through 66 obs over 1545 days.
TS = 1
Cumulative PS -1.95
Highest PS -1.96 one (That's the TS 1) of 7 VIs on 11/10/2103 (PS -1.96 to -7.37)
Totals VIs 45 from 2046-2109

THe JPL sbdb page and NEODyS show 69 obs over 1548 days.

NEODyS has one TS 1, PS-2.56 on 11/10/2103, one of 14 on that date (and there's one on Nov 8 as well)
PS range -2.56 to -7.54

NEODyS Totals 94 VI's from 2046-2109.

 

[silylene]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

So the risk has decreased slightly with the newer data.

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

Well, yes and no. The Sentry risk has increased slightly and the NEODyS risk has slightly decreased.

 

[silylene]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

New data, risk up and down slightly.
1563 days of ARC

NeoDYS PS cum = -2.42 (107 solutions)
JPL PS cum = -2.12 (36 solutions)

 

[silylene]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

New data risk significantly less.

NeoDYS, cum PS = -3.50 (78 solutions)

 

[MeteorWayne]

Re: New data on now Torino Scale 1 2005 YU 55 (in 2103)

From SDC:

http://www.space.com/scienceastronomy/p ... 00429.html

"At one time we had classified 2005 YU55 as a potential threat," said Steve Chesley, a scientist with NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. [More asteroid photos.]

Chesley said the new Arecibo observations have allowed astronomers to rule out any chance of 2005 YU55 hitting Earth in the next 100 years. Additional observations will help better refine those projections, he said.

The Arecibo observations revealed some unexpected new details about the nearby space rock.

The astronomers found that the asteroid is about 1,300 feet (400 meters) in size – about a quarter-mile (400 meters) long and twice as big as originally thought. The Arecibo telescope's planetary radar system resolved features on the asteroid down to about 25 feet (7.5 meters).

Asteroid 2005 YU55 was first discovered by astronomer Robert McMillan, of the Spacewatch detection team, on Dec. 28, 2005. And this isn't the only chance astronomers will have to study 2005 YU55.

On Nov. 8, 2011, the asteroid will complete another trip around the sun and swing by Earth again just inside the moon's orbit. It should fly by at a distance of 191,120 miles (307,577 km), about eight-tenths the distance between Earth and the moon. The distance from Earth to the moon is on average about 238,900 miles (384,472 km).

The asteroid poses no risk of impacting the Earth when it returns next year, though astronomers will keep watching its path through space.

 

[3488]

NEA 2005 YU55.

Arecibo radar imaged NEA 2005 YU55.

It is 400 metres wide & very spherical. Some indentations, possibly craters can be seen. Resolution 7.5 metres.

Wonder what type it is?? I assume a Type S (Silicate) asteroid.

Article here. Asteroid 2005 YU55.

Andrew Brown.

 

[MeteorWayne]

Re: New data on 2005 YU 55 (in 2103)

It's been a while since I updated the sbdb info on this asteroid:

Element Value ....Uncertainty (1-sigma) ... Units
e .4290569891829463.... 6.9291e-08
a 1.142705301714156.... 2.3147e-08 AU
q .6524196054372902.... 8.7798e-08 AU
i .5135186678741143.... 6.5019e-06 deg
node 39.30461345173072.... 0.00017709 deg
peri 268.7914422368116 ....0.00017803 deg
M 26.09429914659912.... 1.0416e-06 deg
tp 2455368.159783236972
(2010-Jun-20.65978324) 9.9911e-07 JED
period 446.1694092369392
1.22 1.3556e-05
3.711e-08 d
yr
n .8068684059171373 2.4516e-08 deg/d
Q 1.632990997991023 3.3078e-08 AU

Orbit Determination Parameters # obs. used (total) 738
# delay obs. used 3
# Doppler obs. used 4
data-arc span 1579 days (4.32 yr)
first obs. used 2005-12-24
last obs. used 2010-04-21
planetary ephem. DE405
SB-pert. ephem. SB405-CPV-2
quality code 0
fit RMS .39047
data source ORB
producer Otto Matic
solution date 2010-Apr-29 00:50:06

Additional Information Earth MOID = .00106489 AU
T_jup = 5.400

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 21.877 mag .4326 30 autocmod 2.4a