Occultation event with (6090) Aulis, event index number 1739
Regions able to see the event: Japan
Geocentric closest approach at 2025/12/31 16:52:29 UTC
J2000 position of star is 10:56:19.3 +04:13:35
Equinox of date position of star is 10:57:40.0 +04:05:13
Star is 102 degrees from the moon. Moon is 89% illuminated.
Stellar brightness G=15.9, apparent brightess of occulting body is G=15.1
Use an exposure time of 2.00 seconds with the standard RECON-QHY system.
SNR of 7.3 per integration for unocculted signal
Expected flux drop is 32% with SNR of 2.3 for the occulted depth (per occulted point)
Apparent velocity is 5.7 km/sec on the sky relative to the star, or, 5.8 arcsec/hr.
Position angle of asteroid motion is 40.1 degrees
The recommended exposure time corresponds to 11.3 km per image.
The 1-sigma error in the time of the event is 1.0 seconds.
The 1-sigma cross-track error in the shadow position is 39.9 km.
The sky-plane scale is 3537.4 km/arcsec.
Diameter estimates:
75.2 km assuming a 5% albedo, aximum of 13.3 sec for a central chord
30.7 km assuming a 30% albedo, maximum of 5.4 sec for a central chord
Cross-track diameter of 59.6 km used for deployment plan.
Star training set for 6090_Aulis, (2025/12/31 16:52UT) Object RA Dec mag sep mel Regulus 10:09:45.2 +11:50:21 1.3 14.16 88 58 Leo 11:01:54.2 +03:28:38 4.8 1.22 103 PPM 157350 10:57:51.7 +05:08:01 7.8 1.05 101 PPM 157383 10:59:44.0 +04:25:00 10.0 0.61 102 PPM 157365 10:58:28.9 +04:19:28 10.7 0.31 102 6090_Aulis 10:57:40.0 +04:05:13 15.1 102 Positions are for equinox of date
This table contains the target star visibility for registered Japan sites that are relevant for this occultation. This list has been filtered to only those sites that can see the field and are within range of the shadow given the uncertainties. The observing time range has been calculated to cover the time of the event at each site with allowances for the event timing uncertainty plus time for obtaining a pre and post event baseline lightcurve. This set of stations has a 11.0 % chance of getting at least one chord. There is a 0.0% chance of 2 or more chords assuming clear weather for all.
| Site Name | Site mid-time (UT) |
Sun alt (deg) |
Sky | Moon | Star alt (deg) |
Star az (deg) |
Target | Observing Time | Xtrack (km) |
Prob |
|---|---|---|---|---|---|---|---|---|---|---|
| Sapporo | 16:47:30 | -56.6 | Dark | Up | 42.7 | 136.5 | Up | 16:48:27-16:54:27 | 225.8 | 0.000 | Akita | 16:48:32 | -58.7 | Dark | Up | 44.5 | 133.1 | Up | 16:48:59-16:54:59 | 191.1 | 0.000 | Niigata | 16:49:08 | -60.0 | Dark | Up | 45.2 | 130.7 | Up | 16:48:38-16:54:38 | 188.7 | 0.000 | Tokyo | 16:49:39 | -60.1 | Dark | Up | 47.1 | 129.7 | Up | 16:45:32-16:51:32 | 73.5 | 0.110 |
Star training set for 6090_Aulis, (2025/12/31 16:52UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 14.16 88 58 Leo 11:00:33.7 +03:37:02 4.8 1.22 103 PPM 157350 10:56:30.9 +05:16:23 7.8 1.05 101 PPM 157383 10:58:23.3 +04:33:23 10.0 0.61 102 PPM 157365 10:57:08.2 +04:27:50 10.7 0.31 102 6090_Aulis 10:56:19.3 +04:13:35 15.1 102 Positions are for J2000