| Parameter |
Value |
| Designation |
C/2015 M1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-05-15T16:23:58.865280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:13Z |
| Obs used |
66 |
| NEO |
- |
| M1 |
15.900 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-06-30.0000000 |
| e |
0.99457925 |
| q (au) |
2.091599 |
| a (au) |
385.850445 |
| i (deg) |
57.309532 |
| Ω (om, deg) |
100.291624 |
| ω (w, deg) |
163.983025 |
| M (ma, deg) |
0.005893 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.909 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.909 |
| n |
2.000 |
| gf |
0.933 |
| gb |
-1.000 |
| k |
0.998 |
| δ90 |
1.000 |
| 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 |
05:01:36.03 |
-16:44:19.0 |
HIP 23445 |
35.97 |
| 2026-09-20 12:00 |
05:01:35.27 |
-16:44:57.9 |
HIP 23445 |
36.64 |
| 2026-09-21 00:00 |
05:01:34.48 |
-16:45:36.9 |
HIP 23445 |
37.32 |
| 2026-09-21 12:00 |
05:01:33.64 |
-16:46:15.8 |
HIP 23445 |
37.99 |
| 2026-09-22 00:00 |
05:01:32.77 |
-16:46:54.7 |
HIP 23445 |
38.68 |
| 2026-09-22 12:00 |
05:01:31.85 |
-16:47:33.6 |
HIP 23445 |
39.36 |
| 2026-09-23 00:00 |
05:01:30.90 |
-16:48:12.4 |
HIP 23445 |
40.05 |
| 2026-09-23 12:00 |
05:01:29.90 |
-16:48:51.3 |
HIP 23445 |
40.73 |
| 2026-09-24 00:00 |
05:01:28.87 |
-16:49:30.0 |
HIP 23445 |
41.43 |
| 2026-09-24 12:00 |
05:01:27.80 |
-16:50:08.8 |
HIP 23512 |
41.93 |
| 2026-09-25 00:00 |
05:01:26.68 |
-16:50:47.5 |
HIP 23512 |
41.61 |
| 2026-09-25 12:00 |
05:01:25.53 |
-16:51:26.2 |
HIP 23512 |
41.31 |
| 2026-09-26 00:00 |
05:01:24.34 |
-16:52:04.8 |
HIP 23512 |
41.02 |
| 2026-09-26 12:00 |
05:01:23.11 |
-16:52:43.4 |
HIP 23512 |
40.75 |
| 2026-09-27 00:00 |
05:01:21.84 |
-16:53:21.9 |
HIP 23350 |
40.10 |
| 2026-09-27 12:00 |
05:01:20.54 |
-16:54:00.4 |
HIP 23350 |
39.46 |
| 2026-09-28 00:00 |
05:01:19.19 |
-16:54:38.8 |
HIP 23350 |
38.82 |
| 2026-09-28 12:00 |
05:01:17.80 |
-16:55:17.2 |
HIP 23350 |
38.18 |
| 2026-09-29 00:00 |
05:01:16.38 |
-16:55:55.4 |
HIP 23350 |
37.54 |
| 2026-09-29 12:00 |
05:01:14.92 |
-16:56:33.7 |
HIP 23350 |
36.91 |
| 2026-09-30 00:00 |
05:01:13.41 |
-16:57:11.8 |
HIP 23350 |
36.29 |
| 2026-09-30 12:00 |
05:01:11.87 |
-16:57:49.9 |
HIP 23350 |
35.67 |
| 2026-10-01 00:00 |
05:01:10.29 |
-16:58:27.9 |
HIP 23350 |
35.06 |
| 2026-10-01 12:00 |
05:01:08.68 |
-16:59:05.8 |
HIP 23350 |
34.45 |
| 2026-10-02 00:00 |
05:01:07.02 |
-16:59:43.7 |
HIP 23350 |
33.85 |
| 2026-10-02 12:00 |
05:01:05.33 |
-17:00:21.4 |
HIP 23350 |
33.26 |
| 2026-10-03 00:00 |
05:01:03.59 |
-17:00:59.1 |
HIP 23350 |
32.68 |
| 2026-10-03 12:00 |
05:01:01.82 |
-17:01:36.7 |
HIP 23350 |
32.11 |
| 2026-10-04 00:00 |
05:01:00.01 |
-17:02:14.2 |
HIP 23350 |
31.55 |
| 2026-10-04 12:00 |
05:00:58.16 |
-17:02:51.5 |
HIP 23350 |
31.00 |
| 2026-10-05 00:00 |
05:00:56.28 |
-17:03:28.8 |
HIP 23350 |
30.46 |
| 2026-10-05 12:00 |
05:00:54.36 |
-17:04:06.0 |
HIP 23350 |
29.94 |
| 2026-10-06 00:00 |
05:00:52.39 |
-17:04:43.0 |
HIP 23350 |
29.43 |
| 2026-10-06 12:00 |
05:00:50.40 |
-17:05:20.0 |
HIP 23350 |
28.94 |
| 2026-10-07 00:00 |
05:00:48.36 |
-17:05:56.8 |
HIP 23350 |
28.46 |
| 2026-10-07 12:00 |
05:00:46.29 |
-17:06:33.5 |
HIP 23350 |
28.01 |
| 2026-10-08 00:00 |
05:00:44.18 |
-17:07:10.1 |
HIP 23350 |
27.57 |
| 2026-10-08 12:00 |
05:00:42.03 |
-17:07:46.6 |
HIP 23350 |
27.15 |
| 2026-10-09 00:00 |
05:00:39.84 |
-17:08:22.9 |
HIP 23306 |
26.74 |
| 2026-10-09 12:00 |
05:00:37.62 |
-17:08:59.1 |
HIP 23306 |
26.16 |
| 2026-10-10 00:00 |
05:00:35.36 |
-17:09:35.1 |
HIP 23306 |
25.60 |
| 2026-10-10 12:00 |
05:00:33.07 |
-17:10:11.0 |
HIP 23306 |
25.05 |
| 2026-10-11 00:00 |
05:00:30.74 |
-17:10:46.8 |
HIP 23306 |
24.53 |