As many NEOphiles may have noticed, the largest of the “lost” NEOs was identified recently by Andrea Boattini (of the CSS), with some help from Giovanni Valsecchi (link). The MPC contributed by adding an additional opposition with the short-arc object 1997 VB1. The resulting orbit and identifications (and short narrative) were published in MPEC 2011-N25.
Andrea identified the newly-designated NEO 2011 NQ with 1984 QY1 based on the concept of ‘orbit-orbit identification’. Using this technique, identifications are suggested based very simply on similarity of orbital elements. Similar elements generally means a similarity in the shape and orientation of the orbit. Even if the orbital period is highly uncertain, similarly aligned and inclined orbits can fairly reliably be identified and linked as a single object. For simplicity, I’ve included the argument of perihelion, the inclination, the eccentricity, and the longitude of ascending node for the short-arc orbits for 1984 QY1 and 2011 NQ. Perhaps now it can be seen that these objects might be one and the same based on this limited and rather uncertain information:
| Object | ω (°) | i (°) | e | Ω (°) |
|---|---|---|---|---|
| 1984 QY1 | 335.4 | 15.5 | 0.92 | 144.1 |
| 2011 NQ | 337.3 | 14.5 | 0.90 | 142.3 |
Other famous historical cases of identifications using the orbit-orbit identification method are (719) Albert (identified by G. V. Williams), 1937 UB (Hermes) (identified by T. B. Spahr and A. Boattini), and 1950 DA (identified by C. Bardwell).
The list of large, lost NEOs is now down to just a handful of objects. The most interesting from an MPC perspective are 1972 RB, 1979 XB, and 1987 SF3, these being the oldest and largest of the objects left.
Potential NEO discoverers take heart! 1984 QY1 was repeatedly above 18th magnitude when at modest solar elongations of ~90°. An object such as this would be easily discoverable with amateur observing equipment. Concentrating on areas of the sky the large surveys don’t cover, or observing when they aren’t doing it due to the Summer Monsoon in Arizona, would be a good starting strategy for those amateur astronomers with a hunger for discovery. This particular time window is open now for the next 1 to 2 months. Take out your telescopes and make the most of it!
—T. B. Spahr
Director, MPC
No related posts.