| Parameter |
Value |
| Designation |
C/2012 A1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-11-29T15:21:03.746880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:59Z |
| Obs used |
322 |
| NEO |
- |
| M1 |
10.100 |
| K1 |
5.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-12-26.0000000 |
| e |
1.00119496 |
| q (au) |
7.604434 |
| a (au) |
-6363.768778 |
| i (deg) |
120.900017 |
| Ω (om, deg) |
277.972039 |
| ω (w, deg) |
191.758696 |
| M (ma, deg) |
-0.000657 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.521 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.521 |
| n |
2.000 |
| gf |
0.822 |
| gb |
-0.955 |
| k |
1.000 |
| δ90 |
2.925 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
22:44:48.05 |
-59:05:12.3 |
HIP 112569 |
34.35 |
| 2026-07-29 12:00 |
22:44:39.38 |
-59:05:54.7 |
HIP 112569 |
35.65 |
| 2026-07-30 00:00 |
22:44:30.66 |
-59:06:36.8 |
HIP 112569 |
36.94 |
| 2026-07-30 12:00 |
22:44:21.90 |
-59:07:18.5 |
HIP 112569 |
38.24 |
| 2026-07-31 00:00 |
22:44:13.09 |
-59:07:59.9 |
HIP 112569 |
39.53 |
| 2026-07-31 12:00 |
22:44:04.25 |
-59:08:40.8 |
HIP 112569 |
40.83 |
| 2026-08-01 00:00 |
22:43:55.35 |
-59:09:21.5 |
HIP 112297 |
41.77 |
| 2026-08-01 12:00 |
22:43:46.42 |
-59:10:01.7 |
HIP 111834 |
41.74 |
| 2026-08-02 00:00 |
22:43:37.44 |
-59:10:41.6 |
HIP 111834 |
41.10 |
| 2026-08-02 12:00 |
22:43:28.43 |
-59:11:21.1 |
HIP 111834 |
40.49 |
| 2026-08-03 00:00 |
22:43:19.37 |
-59:12:00.2 |
HIP 111834 |
39.91 |
| 2026-08-03 12:00 |
22:43:10.27 |
-59:12:38.9 |
HIP 111834 |
39.36 |
| 2026-08-04 00:00 |
22:43:01.14 |
-59:13:17.3 |
HIP 111834 |
38.84 |
| 2026-08-04 12:00 |
22:42:51.96 |
-59:13:55.2 |
HIP 111834 |
38.35 |
| 2026-08-05 00:00 |
22:42:42.74 |
-59:14:32.8 |
HIP 111834 |
37.90 |
| 2026-08-05 12:00 |
22:42:33.49 |
-59:15:09.9 |
HIP 111834 |
37.48 |
| 2026-08-06 00:00 |
22:42:24.20 |
-59:15:46.7 |
HIP 111834 |
37.10 |
| 2026-08-06 12:00 |
22:42:14.88 |
-59:16:23.0 |
HIP 111834 |
36.75 |
| 2026-08-07 00:00 |
22:42:05.52 |
-59:16:58.9 |
HIP 111834 |
36.44 |
| 2026-08-07 12:00 |
22:41:56.12 |
-59:17:34.4 |
HIP 111834 |
36.17 |
| 2026-08-08 00:00 |
22:41:46.69 |
-59:18:09.5 |
HIP 111834 |
35.95 |
| 2026-08-08 12:00 |
22:41:37.23 |
-59:18:44.2 |
HIP 111834 |
35.76 |
| 2026-08-09 00:00 |
22:41:27.73 |
-59:19:18.4 |
HIP 111834 |
35.62 |
| 2026-08-09 12:00 |
22:41:18.20 |
-59:19:52.3 |
HIP 111648 |
35.09 |
| 2026-08-10 00:00 |
22:41:08.64 |
-59:20:25.6 |
HIP 111648 |
33.75 |
| 2026-08-10 12:00 |
22:40:59.04 |
-59:20:58.6 |
HIP 111648 |
32.41 |
| 2026-08-11 00:00 |
22:40:49.42 |
-59:21:31.1 |
HIP 111648 |
31.07 |
| 2026-08-11 12:00 |
22:40:39.77 |
-59:22:03.1 |
HIP 111648 |
29.73 |
| 2026-08-12 00:00 |
22:40:30.09 |
-59:22:34.7 |
HIP 111648 |
28.39 |
| 2026-08-12 12:00 |
22:40:20.38 |
-59:23:05.9 |
HIP 111648 |
27.04 |
| 2026-08-13 00:00 |
22:40:10.65 |
-59:23:36.6 |
HIP 111648 |
25.70 |
| 2026-08-13 12:00 |
22:40:00.88 |
-59:24:06.8 |
HIP 111648 |
24.36 |
| 2026-08-14 00:00 |
22:39:51.10 |
-59:24:36.6 |
HIP 111648 |
23.02 |
| 2026-08-14 12:00 |
22:39:41.29 |
-59:25:05.9 |
HIP 111648 |
21.68 |
| 2026-08-15 00:00 |
22:39:31.45 |
-59:25:34.8 |
HIP 111648 |
20.34 |
| 2026-08-15 12:00 |
22:39:21.59 |
-59:26:03.2 |
HIP 111648 |
19.01 |
| 2026-08-16 00:00 |
22:39:11.71 |
-59:26:31.1 |
HIP 111648 |
17.67 |
| 2026-08-16 12:00 |
22:39:01.81 |
-59:26:58.5 |
HIP 111648 |
16.33 |
| 2026-08-17 00:00 |
22:38:51.89 |
-59:27:25.5 |
HIP 111648 |
15.00 |
| 2026-08-17 12:00 |
22:38:41.94 |
-59:27:52.0 |
HIP 111648 |
13.67 |
| 2026-08-18 00:00 |
22:38:31.98 |
-59:28:18.0 |
HIP 111648 |
12.34 |
| 2026-08-18 12:00 |
22:38:22.00 |
-59:28:43.5 |
HIP 111648 |
11.01 |
| 2026-08-19 00:00 |
22:38:12.01 |
-59:29:08.6 |
HIP 111648 |
9.69 |