| 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) |
| 2026-07-29 00:00 |
04:59:19.33 |
-15:44:29.6 |
HIP 23237 |
10.65 |
| 2026-07-29 12:00 |
04:59:22.42 |
-15:44:53.6 |
HIP 23237 |
9.82 |
| 2026-07-30 00:00 |
04:59:25.48 |
-15:45:17.9 |
HIP 23237 |
8.99 |
| 2026-07-30 12:00 |
04:59:28.51 |
-15:45:42.5 |
HIP 23237 |
8.18 |
| 2026-07-31 00:00 |
04:59:31.51 |
-15:46:07.3 |
HIP 23237 |
7.38 |
| 2026-07-31 12:00 |
04:59:34.48 |
-15:46:32.4 |
HIP 23237 |
6.58 |
| 2026-08-01 00:00 |
04:59:37.42 |
-15:46:57.7 |
HIP 23237 |
5.81 |
| 2026-08-01 12:00 |
04:59:40.34 |
-15:47:23.3 |
HIP 23237 |
5.06 |
| 2026-08-02 00:00 |
04:59:43.22 |
-15:47:49.1 |
HIP 23237 |
4.34 |
| 2026-08-02 12:00 |
04:59:46.08 |
-15:48:15.2 |
HIP 23237 |
3.66 |
| 2026-08-03 00:00 |
04:59:48.90 |
-15:48:41.5 |
HIP 23237 |
3.07 |
| 2026-08-03 12:00 |
04:59:51.70 |
-15:49:08.1 |
HIP 23237 |
2.60 |
| 2026-08-04 00:00 |
04:59:54.46 |
-15:49:34.9 |
HIP 23237 |
2.33 |
| 2026-08-04 12:00 |
04:59:57.20 |
-15:50:02.0 |
HIP 23237 |
2.33 |
| 2026-08-05 00:00 |
04:59:59.90 |
-15:50:29.3 |
HIP 23237 |
2.59 |
| 2026-08-05 12:00 |
05:00:02.57 |
-15:50:56.8 |
HIP 23237 |
3.04 |
| 2026-08-06 00:00 |
05:00:05.21 |
-15:51:24.6 |
HIP 23237 |
3.62 |
| 2026-08-06 12:00 |
05:00:07.82 |
-15:51:52.6 |
HIP 23237 |
4.26 |
| 2026-08-07 00:00 |
05:00:10.40 |
-15:52:20.9 |
HIP 23237 |
4.95 |
| 2026-08-07 12:00 |
05:00:12.94 |
-15:52:49.4 |
HIP 23237 |
5.65 |
| 2026-08-08 00:00 |
05:00:15.46 |
-15:53:18.1 |
HIP 23237 |
6.38 |
| 2026-08-08 12:00 |
05:00:17.94 |
-15:53:47.0 |
HIP 23237 |
7.11 |
| 2026-08-09 00:00 |
05:00:20.39 |
-15:54:16.2 |
HIP 23237 |
7.84 |
| 2026-08-09 12:00 |
05:00:22.81 |
-15:54:45.6 |
HIP 23237 |
8.58 |
| 2026-08-10 00:00 |
05:00:25.19 |
-15:55:15.2 |
HIP 23237 |
9.32 |
| 2026-08-10 12:00 |
05:00:27.54 |
-15:55:45.1 |
HIP 23237 |
10.07 |
| 2026-08-11 00:00 |
05:00:29.86 |
-15:56:15.1 |
HIP 23237 |
10.81 |
| 2026-08-11 12:00 |
05:00:32.14 |
-15:56:45.4 |
HIP 23237 |
11.55 |
| 2026-08-12 00:00 |
05:00:34.39 |
-15:57:15.9 |
HIP 23237 |
12.28 |
| 2026-08-12 12:00 |
05:00:36.61 |
-15:57:46.6 |
HIP 23237 |
13.02 |
| 2026-08-13 00:00 |
05:00:38.79 |
-15:58:17.5 |
HIP 23237 |
13.75 |
| 2026-08-13 12:00 |
05:00:40.94 |
-15:58:48.6 |
HIP 23237 |
14.48 |
| 2026-08-14 00:00 |
05:00:43.05 |
-15:59:19.9 |
HIP 23237 |
15.21 |
| 2026-08-14 12:00 |
05:00:45.13 |
-15:59:51.4 |
HIP 23237 |
15.93 |
| 2026-08-15 00:00 |
05:00:47.18 |
-16:00:23.1 |
HIP 23237 |
16.65 |
| 2026-08-15 12:00 |
05:00:49.19 |
-16:00:55.0 |
HIP 23237 |
17.37 |
| 2026-08-16 00:00 |
05:00:51.16 |
-16:01:27.1 |
HIP 23237 |
18.09 |
| 2026-08-16 12:00 |
05:00:53.10 |
-16:01:59.4 |
HIP 23237 |
18.80 |
| 2026-08-17 00:00 |
05:00:55.01 |
-16:02:31.9 |
HIP 23237 |
19.51 |
| 2026-08-17 12:00 |
05:00:56.87 |
-16:03:04.5 |
HIP 23237 |
20.21 |
| 2026-08-18 00:00 |
05:00:58.71 |
-16:03:37.4 |
HIP 23237 |
20.92 |
| 2026-08-18 12:00 |
05:01:00.51 |
-16:04:10.4 |
HIP 23445 |
20.48 |
| 2026-08-19 00:00 |
05:01:02.27 |
-16:04:43.6 |
HIP 23445 |
19.92 |