11842 Kap'bos (1987 BR1) vs 436415 (2011 AW46)

11842 Kap'bos (1987 BR1) is an interesting asteroid indeed!

First of all, looking at proper elements (see this page), this asteroid has already been recognized to be associated to (228747) 2002 VH3

Furthermore, but this is not sure, it may be even more strictly associated to 436415 (2011 AW46)

JPL Small-Body Database Browser

11842 Kap'bos (1987 BR1)
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 14 (heliocentric ecliptic J2000)

Element	Value	Uncertainty (1-sigma)	Units
e	.09426143976452217	5.4457e-08
a	2.250221196226988	1.1502e-08	AU
q	2.038112106481987	1.1993e-07	AU
i	3.688461615022471	5.8652e-06	deg
node	272.8444791596755	7.5115e-05	deg
peri	172.3596586176659	8.1653e-05	deg
M	181.7294574254017	3.145e-05	deg
tp	2457811.038885071140 (2017-Feb-26.53888507)	0.00010929	JED
period	1232.923821576616 3.38	9.4533e-06 2.588e-08	d yr
n	.2919888428626886	2.2388e-09	deg/d
Q	2.462330285971989	1.2586e-08	AU

436415 (2011 AW46) 
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 8 (heliocentric ecliptic J2000)

Element Value Uncertainty (1-sigma)   Units  e .09435201650783409 1.8231e-07   a 2.25006679453928 5.9552e-08 AU q 2.03776845519718 4.095e-07 AU i 3.688904837606787 1.5844e-05 deg node 272.8087674388969 0.00022201 deg peri 172.3636156199904 0.0002396 deg M 151.7058568204286 9.5288e-05 deg tp 2456680.993016870443 (2014-Jan-23.49301687) 0.00031517 JED period 1232.7969258828 3.38 4.8942e-05 1.34e-07 d yr n .2920188981994789 1.1593e-08 deg/d Q 2.462365133881379 6.5171e-08 AU

This is the result of a simulation made with Mercury6 software (graphs made with package R):

Looking at nominal parameters, it seems that these two asteroids had a very close encounter (nearly 9000 km) with a relative velocity of about 30 cm/s about 11500 years ago.

I do not know whether this is true and, if yes, whether this is just a coincidence or these two asteroids separated in that moment from a common body.

Kind Regards,
Alessandro Odasso

421781 (2014 QG22) vs 53576 (2000 CS47)

These two asteroids are a potentially interesting couple.
I do not know if this couple is already known and if it is really a couple with a common origin.

Let's look at the JPL data, showing very similar orbital parameters:
421781 (2014 QG22)
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 5 (heliocentric ecliptic J2000)

Element	Value	Uncertainty (1-sigma)	Units
e	.1415490034245739	7.6497e-08
a	2.219666740174171	5.0262e-08	AU
q	1.905475125167845	1.6225e-07	AU
i	5.547751979163497	1.1933e-05	deg
node	270.894647775993	0.00023172	deg
peri	334.1685226014454	0.00025596	deg
M	170.5342535281013	0.00011344	deg
tp	2456628.311384753553 (2013-Dec-01.81138475)	0.00037629	JED
period	1207.897517520007 3.31	4.1027e-05 1.123e-07	d yr
n	.2980385295758646	1.0123e-08	deg/d
Q	2.533858355180498	5.7376e-08	AU

 Orbit Determination Parameters

# obs. used (total)      49      data-arc span      3697 days (10.12 yr)      first obs. used      2004-08-14      last obs. used      2014-09-28      planetary ephem.      DE431      SB-pert. ephem.      SB431-BIG16      condition code      0      fit RMS      .55494      data source      ORB      producer      Otto Matic      solution date      2015-Jan-08 13:35:22

Additional Information

Earth MOID = .893565 AU

T_jup = 3.631

53576 (2000 CS47)
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 11 (heliocentric ecliptic J2000)

Element	Value	Uncertainty (1-sigma)	Units
e	.1413172303277337	5.195e-08
a	2.219866104654218	1.5604e-08	AU
q	1.906160775046069	1.1284e-07	AU
i	5.548153406788004	6.1614e-06	deg
node	270.899183954788	6.9605e-05	deg
peri	334.2072656882382	7.5251e-05	deg
M	151.5995810376835	2.9164e-05	deg
tp	2456691.773809093385 (2014-Feb-03.27380909)	9.8063e-05	JED
period	1208.060256319952 3.31	1.2737e-05 3.487e-08	d yr
n	.2979983805581422	3.142e-09	deg/d
Q	2.533571434262367	1.7809e-08	AU

Orbit Determination Parameters

# obs. used (total)      610      data-arc span      7436 days (20.36 yr)      first obs. used      1994-07-08      last obs. used      2014-11-16      planetary ephem.      DE431      SB-pert. ephem.      SB431-BIG16      condition code      0      fit RMS      .49974      data source      ORB      producer      Otto Matic      solution date      2015-Mar-09 16:42:10

Additional Information

Earth MOID = .894238 AU

T_jup = 3.631

 I tried to run the Mercury simulator (BS2 integrator, timestep 1 day) with the nominal parameters, with this result (graph done with the R package)

Kind Regards,
Alessandro Odasso

2002 UP11 vs 2015 VF105

See update about this case:
https://groups.yahoo.com/neo/groups/mpml/conversations/messages/31516

=================================
2002 UP11 and 2015 VF105 have similar orbit parameters.
The uncertainty for 2015 VF105 is unknown and I do not find its observations.


Using the Mercury software, it seems that they had a relative close approach on May 8th, 2001 when their nominal relative distance and velocity were:

• distance 0.00147 AU
• velocity: ca 5 m/s

Maybe in the future, when further observations will be available, it will be possible to study them looking for a common origin

JPL Small-Body Database Browser:

(2002 UP11)

Classification: Mars-crossing Asteroid          SPK-ID: 3224224

[ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters ]

[ show orbit diagram ]

Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB Reference: JPL 2 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .382955379120253 0.00010057 a 2.187589320416579 0.00042822 AU q 1.349840222857032 4.6502e-05 AU i 22.87063099452443 0.0044292 deg node 43.70403288617293 0.0014051 deg peri 62.82185003664876 0.00090087 deg M 293.5443079306065 0.40392 deg tp 2457418.660842947343 (2016-Jan-31.16084295) 1.39 JED period 1181.808525581734 3.24 0.34701 0.0009501 d yr n .3046178735449497 8.9443e-05 deg/d Q 3.025338417976127 0.0005922 AU

Orbit Determination Parameters    # obs. used (total)      17      data-arc span      49 days      first obs. used      2002-10-04      last obs. used      2002-11-22      planetary ephem.      DE431      SB-pert. ephem.      SB431-BIG16      condition code      6      fit RMS      .53879      data source      ORB      producer      Otto Matic      solution date      2014-Jun-13 03:11:31   Additional Information  Earth MOID = .485591 AU   T_jup = 3.482

(2015 VF105)

Classification: Mars-crossing Asteroid          SPK-ID: 3734494

[ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters ]

[ show orbit diagram ]

Orbital Elements at Epoch 2457300.5 (2015-Oct-05.0) TDB Reference: E2015-VE1 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e 0.3831181 n/a a 2.1883016 n/a AU q 1.3499236 n/a AU i 22.88002 n/a deg node 43.69986 n/a deg peri 62.82823 n/a deg M 323.14568 n/a deg tp 2457421.5445051 (2016-Feb-03.04450510) n/a JED period 1182.3857240 3.24 n/a n/a d yr n 0.30446917 n/a deg/d Q 3.0266796 n/a AU

Orbit Determination Parameters    # obs. used (total)      21      data-arc span      62 days      first obs. used      2015-09-11      last obs. used      2015-11-12      # oppositions      1      two-body model      T      fit RMS      0.13      data source      MPC:mp1      producer      MPCW   Additional Information  T_jup = 3.482

Graph

Kind Regards,
Alessandro Odasso

(356713) 2010 GS25 vs 2014 QX220

These two asteroids have similar orbits:
(356713) 2010 GS25
2014 QX220


Mean motion uncertainty a little less than 10^-8 deg/day

I wonder if these two asteroids originated from a common parent body about 10Kyears ago.

Using the Mercury simulator by John Chambers on the nominal parameters, we have this result:

Year -8168
Distance = 0.0000232 (AU) about 3500 km
Relative Velocity = 7.270e-08 (AU/Day) about 12 cm/s


Kind Regards,
Alessandro Odasso

Question about divorced asteroid pairs orbit stability

I refer to the list of most recently potentially divorced binary pairs found by Robert D, Matson.

I used JPL Horizons Web Interface to get the orbital data for (63440) 2001 MD30 and (331933) 2004 TV14

Then, I used the Mercury simulator to look at their past and future orbits and I used the R package to plot the results:

Let's look at the past:

Let's now look at the future:

 

I do not know if it is common for two divorced asteroid pairs to continue to stay on a very similar orbit. At least in this case, these asteroids will come again very very near. 

Not clear if this is a proof of the fact that they are a divorced pair or this is just a nice example of two asteroids that have nothing to do but are by chance on a (almost) collision orbit.

The nominal result for the event "minimum distance" is:

• date: 25-May-5418
• minimum distance : 8.95e-06 (AU) ... just about 1300 km
• relative velocity:       2.16e-07 ( AU/day ) ... just about 0.37 m/s

uncertainty error : unknown

Kind Regards,

Alessandro Odasso

Asteroids with high perihelion precession rates

As described in this MPML message, an interesting study is under way: its goal is to
measure the perihelion precession rates for a number of objects to quantify the effects of general relativity (GR) and solar oblateness.

More at http://mel.epss.ucla.edu/jlm/research/NEAs/GR/

Based on this list, we can get the following data:

Symbol Description H Absolute magnitude a Semi-major axis (au) e Eccentricity i Inclination (deg) P Orbital period (days) SLR Semilatus rectum (au) dr Range rate due to GR/J2 (km/y) dw Perihelion shift (asec/century) arc Length of optical arc nobs Number of optical observations

Let's visually see how SLR, dr and dw are related:

• Graph 1 - dw vs SLR (parameter = quartile of dr)
  

• Graph 2 - dw vs dr (parameter = quartile of SLR) 
  

Graph 1 - dw vs SLR (parameter = quartile of dr)

> quantile of dr (km/y)
     0%     25%     50%     75%    100% 
 48.800  55.425  66.300  80.300 171.000 

Graph 2 - dw vs dr (parameter = quartile of SLR)

> quantileof SLR (au)
     0%     25%     50%     75%    100% 
0.17400 0.37400 0.48550 0.58675 0.66400

It seems to me that both graphs show (as expected) that the more an asteroid comes near the sun the more important is the dr effect.

The same is true for the dw effect but I do not understand this:

• dw belongs to an area defined by two almost linear boundaries (the slope of the higher boundary is greater than the slope of the lower boundary , thus we see a "triangular shape"...)
  Why does this happen?

Multiple regression

Coming back to easier considerations, there may be another way to show the relation between dw, dr and SLR.

Look at the multiple regression fit that predicts dw based on SLR and dr taking into
account the interaction between SLR and dr:

> summary(fit)

Call:
lm(formula = dw ~ SLR * dr, data = p)

Residuals:
     Min       1Q   Median       3Q      Max 
-2.15438 -0.30660  0.04085  0.24131  3.13628 

Coefficients:
              Estimate Std. Error t value Pr(>|t|)    
(Intercept) -27.820350   0.981042 -28.358  < 2e-16 ***
SLR          -6.124334   1.318151  -4.646 1.15e-05 ***
dr            0.146494   0.006126  23.912  < 2e-16 ***
SLR:dr        1.038595   0.028026  37.059  < 2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 0.5601 on 90 degrees of freedom
Multiple R-squared:  0.9863, Adjusted R-squared:  0.9859 
F-statistic:  2163 on 3 and 90 DF,  p-value: < 2.2e-16

dw - Fitted values vs original values

This is the normal probability plot used to see how much the residuals of the model are
normally distributed:

Kind regards,
Alessandro Odasso

Near Earth Asteroids - Low Delta-V - Frame of reference co-rotating with earth

Due to their earth like orbit, these low delta-v asteroids move slowly when seen from earth. The resulting movement is very nice.

I tried to visualize asteroids which are likely to be lunar ejecta. I also add Bennu that moves much faster but it is interesting to see how it gets "near" to the earth during the Osiris-REx mission 

All the other asteroids are sorted by Delta-V.

The last two asteroids have a very low eccentricity.

The following graphs show their movement in the next 10 years:

• Sun is at (0,0)
• Earth is at about (1,0)

Bennu
a-e-i

1.126  0.204    6.0 

 
2006RH120
a-e-i 

1.033  0.024    0.6

2012TF79
a-e-i

1.050  0.038    1.0

2009BD
a-e-i 

1.062  0.052    1.3

2014WX202
a-e-i 

1.035  0.059    0.4

1991VG
a-e-i 

1.027  0.049    1.4

2013RZ53 (maybe artificial, though not very likely: see this link)
a-e-i

1.013  0.027    2.1

2014WA366
a-e-i 

1.034  0.071    1.6

2014WU200
a-e-i 

1.027  0.072    1.3

2015JD3
a-e-i 

1.058  0.008    2.7

2014TW
a-e-i 

1.029  0.009    9.0

Kind Regards,
Alessandro Odasso