| 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
$$
M_a = (9.596 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.596 |
| n |
2.000 |
| gf |
0.822 |
| gb |
-0.955 |
| k |
1.000 |
| δ90 |
2.186 |
| 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) |
| 2026-03-26 00:00 |
22:48:13.06 |
-56:13:13.9 |
HIP 112764 |
24.84 |
| 2026-03-26 12:00 |
22:48:18.91 |
-56:13:17.7 |
HIP 112764 |
24.34 |
| 2026-03-27 00:00 |
22:48:24.74 |
-56:13:22.0 |
HIP 112764 |
23.87 |
| 2026-03-27 12:00 |
22:48:30.53 |
-56:13:26.7 |
HIP 112764 |
23.43 |
| 2026-03-28 00:00 |
22:48:36.30 |
-56:13:31.9 |
HIP 112764 |
23.02 |
| 2026-03-28 12:00 |
22:48:42.04 |
-56:13:37.6 |
HIP 112764 |
22.64 |
| 2026-03-29 00:00 |
22:48:47.75 |
-56:13:43.8 |
HIP 112764 |
22.28 |
| 2026-03-29 12:00 |
22:48:53.43 |
-56:13:50.3 |
HIP 112764 |
21.97 |
| 2026-03-30 00:00 |
22:48:59.08 |
-56:13:57.4 |
HIP 112764 |
21.68 |
| 2026-03-30 12:00 |
22:49:04.70 |
-56:14:04.9 |
HIP 112764 |
21.43 |
| 2026-03-31 00:00 |
22:49:10.29 |
-56:14:12.9 |
HIP 112764 |
21.21 |
| 2026-03-31 12:00 |
22:49:15.85 |
-56:14:21.3 |
HIP 112839 |
21.02 |
| 2026-04-01 00:00 |
22:49:21.38 |
-56:14:30.2 |
HIP 112839 |
20.36 |
| 2026-04-01 12:00 |
22:49:26.87 |
-56:14:39.6 |
HIP 112839 |
19.71 |
| 2026-04-02 00:00 |
22:49:32.33 |
-56:14:49.4 |
HIP 112839 |
19.07 |
| 2026-04-02 12:00 |
22:49:37.77 |
-56:14:59.6 |
HIP 112839 |
18.44 |
| 2026-04-03 00:00 |
22:49:43.16 |
-56:15:10.4 |
HIP 112839 |
17.81 |
| 2026-04-03 12:00 |
22:49:48.53 |
-56:15:21.5 |
HIP 112839 |
17.19 |
| 2026-04-04 00:00 |
22:49:53.86 |
-56:15:33.2 |
HIP 112839 |
16.58 |
| 2026-04-04 12:00 |
22:49:59.15 |
-56:15:45.3 |
HIP 112839 |
15.99 |
| 2026-04-05 00:00 |
22:50:04.41 |
-56:15:57.8 |
HIP 112839 |
15.40 |
| 2026-04-05 12:00 |
22:50:09.64 |
-56:16:10.8 |
HIP 112839 |
14.82 |
| 2026-04-06 00:00 |
22:50:14.83 |
-56:16:24.3 |
HIP 112839 |
14.26 |
| 2026-04-06 12:00 |
22:50:19.98 |
-56:16:38.2 |
HIP 112839 |
13.71 |
| 2026-04-07 00:00 |
22:50:25.10 |
-56:16:52.5 |
HIP 112839 |
13.17 |
| 2026-04-07 12:00 |
22:50:30.18 |
-56:17:07.3 |
HIP 112839 |
12.66 |
| 2026-04-08 00:00 |
22:50:35.23 |
-56:17:22.6 |
HIP 112839 |
12.16 |
| 2026-04-08 12:00 |
22:50:40.23 |
-56:17:38.3 |
HIP 112839 |
11.68 |
| 2026-04-09 00:00 |
22:50:45.20 |
-56:17:54.4 |
HIP 112839 |
11.22 |
| 2026-04-09 12:00 |
22:50:50.13 |
-56:18:11.0 |
HIP 112839 |
10.79 |
| 2026-04-10 00:00 |
22:50:55.02 |
-56:18:28.1 |
HIP 112839 |
10.39 |
| 2026-04-10 12:00 |
22:50:59.88 |
-56:18:45.6 |
HIP 112839 |
10.02 |
| 2026-04-11 00:00 |
22:51:04.69 |
-56:19:03.5 |
HIP 112839 |
9.68 |
| 2026-04-11 12:00 |
22:51:09.46 |
-56:19:21.9 |
HIP 112839 |
9.38 |
| 2026-04-12 00:00 |
22:51:14.19 |
-56:19:40.8 |
HIP 112839 |
9.12 |
| 2026-04-12 12:00 |
22:51:18.88 |
-56:20:00.1 |
HIP 112839 |
8.90 |
| 2026-04-13 00:00 |
22:51:23.53 |
-56:20:19.8 |
HIP 112839 |
8.73 |
| 2026-04-13 12:00 |
22:51:28.14 |
-56:20:39.9 |
HIP 112839 |
8.61 |
| 2026-04-14 00:00 |
22:51:32.70 |
-56:21:00.6 |
HIP 112839 |
8.53 |
| 2026-04-14 12:00 |
22:51:37.22 |
-56:21:21.6 |
HIP 112892 |
8.12 |
| 2026-04-15 00:00 |
22:51:41.70 |
-56:21:43.1 |
HIP 112892 |
7.74 |
| 2026-04-15 12:00 |
22:51:46.14 |
-56:22:05.0 |
HIP 112892 |
7.39 |
| 2026-04-16 00:00 |
22:51:50.53 |
-56:22:27.4 |
HIP 112892 |
7.10 |