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The Planned "Future Alert List"
Whenever people stumble upon an interesting-looking lightcurve they can advertise it on
the SAPC (Standard Asteroid Photometric Catalogue) and/or CALL site so that after four or
more apparitions (or about six years) we might have a first model of it. If several
asteroids are worked through in that way, we'll have hundreds and hundreds of asteroid
models by the end of the decade! Systematic observations are the key! Use the CALL, MPML, or Asteroid Studies sites to help
coordinate efforts.
Current Alert List
With data from one or two more apparitions, it should be possible to determine the shapes
of the following asteroids.
NEAs
| 1566 Icarus | 1866 Sisyphus | 4197 1982 TA |
| 1685 Toro | 1917 Cuyo | 4954 Eric |
| 1864 Daedalus | 3103 Eger | 5751 Zao |
| 1865 Cerberus | 3122 Florence | 7822 1991 CS |
MBAs
| 5 Astraea | 80 Sappho | 324 Bamberga | 747 Winchester |
| 24 Themis | 83 Beatrix | 334 Chicago | 776 Berbericia |
| 30 Urania | 93 Minerva | 344 Desiderata | 804 Hispania |
| 31 Euphrosyne | 110 Lydia | 369 Aeria | 944 Hidalgo |
| 34 Circe | 114 Kassandra | 377 Campania | 1902 Shaposhnikov |
| 36 Atalante | 125 Liberatrix | 386 Siegena | 3415 Danby |
| 40 Harmonia | 133 Cyrene | 409 Aspasia | |
| 47 Aglaja | 165 Loreley | 416 Vaticana | |
| 48 Doris | 196 Philomela | 419 Aurelia | |
| 51 Nemausa | 218 Bianca | 441 Bathilde | |
| 54 Alexandra | 221 Eos | 471 Papagena | |
| 59 Elpis | 233 Asterope | 480 Hansa | |
| 76 Freia | 238 Hypatia | 487 Venetia | |
| 77 Frigga | 258 Tyche | 505 Cava | |
| 79 Eurynome | 276 Adelheid | 683 Lanzia | |
Frequently Asked Questions
It's probably easiest if people first check which objects on the
list are currently well observable (depending on each observer's location) and then send
me their shortlist. I can then iterate it more by checking which of the targets stand the
best chances.
Q: Do you think the one lightcurve during one dark run would
normally be sufficient, or will a second lightcurve in a subsequent month, at a different
phase angle, be needed?
A: It's certainly good to try and catch different solar
phases during one apparition -- it gives more confidence on the details of the model.
Another good practice is to eliminate potential systematical errors by observing on two
adjacent or at least nearby nights, particularly if the rotation period is not short
enough for overlapping rotational phases during one night (and especially if the period is
so long that one night is not enough for complete rotation coverage). In this way one can
be sure that possible features in lc are really repeated and not artificial.
As to solar phase angles, the basic rule is to get as high a phase angle as possible to
get maximal shadowing effects (and light-scattering behaviour different from the
simple geometric mode at opposition). Both pre- and post-opposition would be good:
illumination from opposite sides should confirm model details.
Q: Is there a point where the percentage of period coverage
overcomes phase angle for you? Obviously we can work objects at higher angles on either
side of opposition but would be constrained by twilight.
A: Yes, this is, of course, the basic tradeoff factor in
lightcurves, and I guess it's best to aim at the best compromise. No good getting a large
phase when there's not much of an observing window. Perhaps a good rule of thumb for one
apparition would be two curves at the largest useful phase angles (to get a meaningful
part of the period covered; more than one night is good for this), and one at a smaller
phase just to get as long a stretch as possible. In this way one should get the most of
the apparition.