| Parameter |
Value |
| Designation |
C/2015 M3 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-08-26T05:34:05.033280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:13Z |
| Obs used |
150 |
| NEO |
- |
| M1 |
14.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-09-03.0000000 |
| e |
0.97327847 |
| q (au) |
3.552414 |
| a (au) |
132.942015 |
| i (deg) |
65.951065 |
| Ω (om, deg) |
143.092842 |
| ω (w, deg) |
123.762544 |
| M (ma, deg) |
0.004995 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.907 + 2.182\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.907 |
| n |
2.182 |
| gf |
0.967 |
| gb |
-0.511 |
| k |
0.800 |
| δ90 |
9.982 |
| 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) |
| 2026-09-20 00:00 |
03:59:16.92 |
-48:17:39.4 |
HIP 18556 |
12.65 |
| 2026-09-20 12:00 |
03:59:14.47 |
-48:18:41.7 |
HIP 18556 |
12.97 |
| 2026-09-21 00:00 |
03:59:11.96 |
-48:19:43.7 |
HIP 18556 |
13.37 |
| 2026-09-21 12:00 |
03:59:09.40 |
-48:20:45.6 |
HIP 18556 |
13.84 |
| 2026-09-22 00:00 |
03:59:06.77 |
-48:21:47.2 |
HIP 18556 |
14.37 |
| 2026-09-22 12:00 |
03:59:04.09 |
-48:22:48.6 |
HIP 18556 |
14.96 |
| 2026-09-23 00:00 |
03:59:01.35 |
-48:23:49.8 |
HIP 18556 |
15.60 |
| 2026-09-23 12:00 |
03:58:58.56 |
-48:24:50.7 |
HIP 18556 |
16.28 |
| 2026-09-24 00:00 |
03:58:55.71 |
-48:25:51.3 |
HIP 18556 |
17.00 |
| 2026-09-24 12:00 |
03:58:52.80 |
-48:26:51.7 |
HIP 18556 |
17.76 |
| 2026-09-25 00:00 |
03:58:49.84 |
-48:27:51.9 |
HIP 18556 |
18.54 |
| 2026-09-25 12:00 |
03:58:46.82 |
-48:28:51.8 |
HIP 18469 |
19.14 |
| 2026-09-26 00:00 |
03:58:43.75 |
-48:29:51.4 |
HIP 18469 |
18.66 |
| 2026-09-26 12:00 |
03:58:40.62 |
-48:30:50.8 |
HIP 18469 |
18.23 |
| 2026-09-27 00:00 |
03:58:37.43 |
-48:31:49.9 |
HIP 18469 |
17.85 |
| 2026-09-27 12:00 |
03:58:34.19 |
-48:32:48.7 |
HIP 18469 |
17.52 |
| 2026-09-28 00:00 |
03:58:30.90 |
-48:33:47.2 |
HIP 18469 |
17.25 |
| 2026-09-28 12:00 |
03:58:27.55 |
-48:34:45.4 |
HIP 18469 |
17.04 |
| 2026-09-29 00:00 |
03:58:24.15 |
-48:35:43.3 |
HIP 18469 |
16.89 |
| 2026-09-29 12:00 |
03:58:20.69 |
-48:36:41.0 |
HIP 18469 |
16.80 |
| 2026-09-30 00:00 |
03:58:17.18 |
-48:37:38.3 |
HIP 18469 |
16.78 |
| 2026-09-30 12:00 |
03:58:13.62 |
-48:38:35.3 |
HIP 18469 |
16.82 |
| 2026-10-01 00:00 |
03:58:10.00 |
-48:39:32.1 |
HIP 18469 |
16.93 |
| 2026-10-01 12:00 |
03:58:06.33 |
-48:40:28.5 |
HIP 18469 |
17.10 |
| 2026-10-02 00:00 |
03:58:02.60 |
-48:41:24.5 |
HIP 18624 |
17.29 |
| 2026-10-02 12:00 |
03:57:58.83 |
-48:42:20.3 |
HIP 18624 |
16.99 |
| 2026-10-03 00:00 |
03:57:55.00 |
-48:43:15.7 |
HIP 18624 |
16.77 |
| 2026-10-03 12:00 |
03:57:51.12 |
-48:44:10.8 |
HIP 18624 |
16.63 |
| 2026-10-04 00:00 |
03:57:47.19 |
-48:45:05.5 |
HIP 18624 |
16.57 |
| 2026-10-04 12:00 |
03:57:43.20 |
-48:45:59.9 |
HIP 18624 |
16.60 |
| 2026-10-05 00:00 |
03:57:39.17 |
-48:46:53.9 |
HIP 18624 |
16.71 |
| 2026-10-05 12:00 |
03:57:35.08 |
-48:47:47.6 |
HIP 18484 |
15.80 |
| 2026-10-06 00:00 |
03:57:30.95 |
-48:48:40.9 |
HIP 18484 |
14.74 |
| 2026-10-06 12:00 |
03:57:26.76 |
-48:49:33.8 |
HIP 18484 |
13.70 |
| 2026-10-07 00:00 |
03:57:22.52 |
-48:50:26.4 |
HIP 18484 |
12.67 |
| 2026-10-07 12:00 |
03:57:18.24 |
-48:51:18.6 |
HIP 18484 |
11.66 |
| 2026-10-08 00:00 |
03:57:13.90 |
-48:52:10.4 |
HIP 18484 |
10.68 |
| 2026-10-08 12:00 |
03:57:09.52 |
-48:53:01.8 |
HIP 18484 |
9.74 |
| 2026-10-09 00:00 |
03:57:05.08 |
-48:53:52.8 |
HIP 18484 |
8.84 |
| 2026-10-09 12:00 |
03:57:00.60 |
-48:54:43.5 |
HIP 18484 |
8.00 |
| 2026-10-10 00:00 |
03:56:56.07 |
-48:55:33.7 |
HIP 18484 |
7.25 |
| 2026-10-10 12:00 |
03:56:51.50 |
-48:56:23.5 |
HIP 18484 |
6.62 |
| 2026-10-11 00:00 |
03:56:46.87 |
-48:57:12.9 |
HIP 18484 |
6.13 |