2015 MM64 versus 2019 van Albada (1935 SX1)

This case may deserve further investigation because (2019) van Albada (1935 SX1) is a known binary asteroid with a satellite, as reported  here by Johnston’s Archive and a  photometric study by Vladimir Benishek, Petr Pravec, Russell Durkee, Marek Husarik.

Confirming a genetic relationship with 2015 MM64 would make the system particularly intriguing.

The nominal solutions show a clear convergence epoch broadly supported by the covariance clones. However, at the selected minimum-median-velocity epoch, all clone combinations remain outside van Albada’s Hill sphere and above the local escape-velocity curve. 

Thus, the case is intriguing but remains inconclusive.

 

Simulation details

Covariance clone convergence summary

Run setup:

- Pair mode, 100 covariance clones per target plus nominal.

- 101 samples per target, 10,201 sample cross-combinations.

- Analysis epoch: JD 2461200.5.

- Objective: minimize median velocity.

- Nominal sample source: covariance.

- Integrator: REBOUND IAS15 in AU-yr-Msun, initial dt 0.3652564 day (0.001 yr), default IAS15 epsilon.

- Massive bodies: Sun; Mercury, Venus, Earth-Moon, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto barycenters; Ceres, Pallas, and Vesta.

- Test particles: all nominal/covariance-clone samples for the 2 targets; clones are massless and do not perturb the massive bodies or each other.

Window window_1:

- Window center: 43768.781000 yr before analysis epoch.

- Selected best time: 43768.013514 yr before analysis epoch.

- Selected-time JD: -13525346.551110.

- Median relative velocity at selected time: 9.172443 m/s.

- Median distance at selected time: 168,300.443 km.

Distance distribution at selected time:

- Minimum combination at selected time: 10,143.336 km.

- p05 / p16: 17,042.759 / 53,341.853 km.

- Median / p84 / p95: 168,300.443 / 555,126.540 / 810,551.880 km.

- Max: 1,091,114.734 km.

- Nominal at selected time: 85,208.192 km.

- Fractions below thresholds: 0.00% < 10,000 km; 33.61% < 100,000 km; 99.01% < 1,000,000 km.

Relative-velocity distribution at selected time:

- Minimum combination at selected time: 0.693410 m/s.

- p05 / p16: 0.991334 / 2.770931 m/s.

- Median / p84 / p95: 9.172443 / 29.927771 / 43.668428 m/s.

- Max: 58.722771 m/s.

- Nominal at selected time: 4.752497 m/s.

- Fractions below thresholds: 5.10% < 1 m/s; 52.48% < 10 m/s.

Let's look at the distance and relative velocity distributions at the time when the median relative velocity was minimum:

Let's put together all pair combinations on the same density plot: