| 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) |
| 2026-06-01 00:00 |
22:54:39.54 |
-57:23:03.9 |
HIP 113330 |
19.73 |
| 2026-06-01 12:00 |
22:54:38.41 |
-57:23:56.5 |
HIP 113330 |
19.85 |
| 2026-06-02 00:00 |
22:54:37.22 |
-57:24:49.3 |
HIP 113330 |
20.02 |
| 2026-06-02 12:00 |
22:54:35.95 |
-57:25:42.3 |
HIP 113330 |
20.24 |
| 2026-06-03 00:00 |
22:54:34.62 |
-57:26:35.4 |
HIP 113330 |
20.51 |
| 2026-06-03 12:00 |
22:54:33.21 |
-57:27:28.8 |
HIP 113330 |
20.82 |
| 2026-06-04 00:00 |
22:54:31.73 |
-57:28:22.2 |
HIP 113330 |
21.17 |
| 2026-06-04 12:00 |
22:54:30.18 |
-57:29:15.8 |
HIP 113330 |
21.57 |
| 2026-06-05 00:00 |
22:54:28.57 |
-57:30:09.6 |
HIP 113330 |
22.01 |
| 2026-06-05 12:00 |
22:54:26.88 |
-57:31:03.5 |
HIP 113022 |
22.19 |
| 2026-06-06 00:00 |
22:54:25.12 |
-57:31:57.6 |
HIP 113022 |
21.27 |
| 2026-06-06 12:00 |
22:54:23.28 |
-57:32:51.8 |
HIP 113022 |
20.35 |
| 2026-06-07 00:00 |
22:54:21.38 |
-57:33:46.1 |
HIP 113022 |
19.42 |
| 2026-06-07 12:00 |
22:54:19.41 |
-57:34:40.6 |
HIP 113022 |
18.49 |
| 2026-06-08 00:00 |
22:54:17.36 |
-57:35:35.2 |
HIP 113022 |
17.55 |
| 2026-06-08 12:00 |
22:54:15.25 |
-57:36:29.9 |
HIP 113022 |
16.61 |
| 2026-06-09 00:00 |
22:54:13.06 |
-57:37:24.7 |
HIP 113022 |
15.66 |
| 2026-06-09 12:00 |
22:54:10.80 |
-57:38:19.6 |
HIP 113022 |
14.71 |
| 2026-06-10 00:00 |
22:54:08.47 |
-57:39:14.7 |
HIP 113022 |
13.76 |
| 2026-06-10 12:00 |
22:54:06.06 |
-57:40:09.9 |
HIP 113022 |
12.80 |
| 2026-06-11 00:00 |
22:54:03.59 |
-57:41:05.1 |
HIP 113022 |
11.84 |
| 2026-06-11 12:00 |
22:54:01.04 |
-57:42:00.5 |
HIP 113022 |
10.87 |
| 2026-06-12 00:00 |
22:53:58.42 |
-57:42:55.9 |
HIP 113022 |
9.90 |
| 2026-06-12 12:00 |
22:53:55.73 |
-57:43:51.4 |
HIP 113022 |
8.93 |
| 2026-06-13 00:00 |
22:53:52.96 |
-57:44:47.1 |
HIP 113022 |
7.96 |
| 2026-06-13 12:00 |
22:53:50.13 |
-57:45:42.8 |
HIP 113022 |
6.99 |
| 2026-06-14 00:00 |
22:53:47.22 |
-57:46:38.5 |
HIP 113022 |
6.02 |
| 2026-06-14 12:00 |
22:53:44.24 |
-57:47:34.4 |
HIP 113022 |
5.06 |
| 2026-06-15 00:00 |
22:53:41.19 |
-57:48:30.3 |
HIP 113022 |
4.12 |
| 2026-06-15 12:00 |
22:53:38.06 |
-57:49:26.2 |
HIP 113022 |
3.21 |
| 2026-06-16 00:00 |
22:53:34.86 |
-57:50:22.2 |
HIP 113022 |
2.39 |
| 2026-06-16 12:00 |
22:53:31.59 |
-57:51:18.3 |
HIP 113022 |
1.79 |
| 2026-06-17 00:00 |
22:53:28.25 |
-57:52:14.4 |
HIP 113022 |
1.67 |
| 2026-06-17 12:00 |
22:53:24.84 |
-57:53:10.5 |
HIP 113022 |
2.12 |
| 2026-06-18 00:00 |
22:53:21.35 |
-57:54:06.7 |
HIP 113022 |
2.89 |
| 2026-06-18 12:00 |
22:53:17.79 |
-57:55:02.9 |
HIP 113022 |
3.79 |
| 2026-06-19 00:00 |
22:53:14.16 |
-57:55:59.1 |
HIP 113022 |
4.76 |
| 2026-06-19 12:00 |
22:53:10.46 |
-57:56:55.3 |
HIP 113022 |
5.76 |
| 2026-06-20 00:00 |
22:53:06.69 |
-57:57:51.6 |
HIP 113022 |
6.78 |
| 2026-06-20 12:00 |
22:53:02.84 |
-57:58:47.8 |
HIP 113022 |
7.81 |
| 2026-06-21 00:00 |
22:52:58.93 |
-57:59:44.1 |
HIP 113022 |
8.86 |
| 2026-06-21 12:00 |
22:52:54.94 |
-58:00:40.3 |
HIP 113022 |
9.91 |
| 2026-06-22 00:00 |
22:52:50.88 |
-58:01:36.6 |
HIP 113022 |
10.97 |