| Parameter |
Value |
| Designation |
P/2015 R1 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-06-25T18:24:22.605120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:14Z |
| Obs used |
257 |
| NEO |
- |
| M1 |
13.500 |
| K1 |
10.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-10-18.0000000 |
| e |
0.63286160 |
| q (au) |
2.165459 |
| a (au) |
5.898208 |
| i (deg) |
22.668327 |
| Ω (om, deg) |
48.514080 |
| ω (w, deg) |
300.537706 |
| M (ma, deg) |
7.859878 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.789 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.789 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.680 |
| k |
0.800 |
| δ90 |
10.000 |
| 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 |
13:37:10.94 |
-01:44:54.9 |
HIP 66499 |
23.01 |
| 2026-09-20 12:00 |
13:37:25.54 |
-01:46:56.8 |
HIP 66499 |
19.67 |
| 2026-09-21 00:00 |
13:37:40.18 |
-01:48:58.8 |
HIP 66499 |
16.70 |
| 2026-09-21 12:00 |
13:37:54.88 |
-01:51:00.8 |
HIP 66499 |
14.35 |
| 2026-09-22 00:00 |
13:38:09.62 |
-01:53:02.8 |
HIP 66499 |
12.98 |
| 2026-09-22 12:00 |
13:38:24.41 |
-01:55:04.8 |
HIP 66499 |
12.90 |
| 2026-09-23 00:00 |
13:38:39.25 |
-01:57:06.8 |
HIP 66499 |
14.15 |
| 2026-09-23 12:00 |
13:38:54.14 |
-01:59:08.8 |
HIP 66499 |
16.44 |
| 2026-09-24 00:00 |
13:39:09.07 |
-02:01:10.8 |
HIP 66499 |
19.41 |
| 2026-09-24 12:00 |
13:39:24.05 |
-02:03:12.9 |
HIP 66686 |
22.69 |
| 2026-09-25 00:00 |
13:39:39.07 |
-02:05:14.9 |
HIP 66686 |
19.06 |
| 2026-09-25 12:00 |
13:39:54.14 |
-02:07:16.9 |
HIP 66686 |
15.76 |
| 2026-09-26 00:00 |
13:40:09.26 |
-02:09:18.9 |
HIP 66686 |
13.03 |
| 2026-09-26 12:00 |
13:40:24.42 |
-02:11:20.9 |
HIP 66686 |
11.31 |
| 2026-09-27 00:00 |
13:40:39.62 |
-02:13:22.9 |
HIP 66686 |
11.11 |
| 2026-09-27 12:00 |
13:40:54.86 |
-02:15:24.8 |
HIP 66686 |
12.49 |
| 2026-09-28 00:00 |
13:41:10.15 |
-02:17:26.8 |
HIP 66686 |
15.05 |
| 2026-09-28 12:00 |
13:41:25.48 |
-02:19:28.7 |
HIP 66686 |
18.29 |
| 2026-09-29 00:00 |
13:41:40.85 |
-02:21:30.5 |
HIP 66922 |
19.50 |
| 2026-09-29 12:00 |
13:41:56.26 |
-02:23:32.4 |
HIP 66922 |
15.21 |
| 2026-09-30 00:00 |
13:42:11.71 |
-02:25:34.2 |
HIP 66922 |
10.94 |
| 2026-09-30 12:00 |
13:42:27.20 |
-02:27:36.0 |
HIP 66922 |
6.79 |
| 2026-10-01 00:00 |
13:42:42.74 |
-02:29:37.7 |
HIP 66922 |
3.27 |
| 2026-10-01 12:00 |
13:42:58.31 |
-02:31:39.4 |
HIP 66922 |
3.69 |
| 2026-10-02 00:00 |
13:43:13.92 |
-02:33:41.0 |
HIP 66922 |
7.42 |
| 2026-10-02 12:00 |
13:43:29.57 |
-02:35:42.6 |
HIP 66922 |
11.63 |
| 2026-10-03 00:00 |
13:43:45.25 |
-02:37:44.2 |
HIP 66922 |
15.95 |
| 2026-10-03 12:00 |
13:44:00.97 |
-02:39:45.6 |
HIP 66922 |
20.32 |
| 2026-10-04 00:00 |
13:44:16.73 |
-02:41:47.1 |
HIP 66922 |
24.71 |
| 2026-10-04 12:00 |
13:44:32.53 |
-02:43:48.4 |
HIP 66922 |
29.12 |
| 2026-10-05 00:00 |
13:44:48.36 |
-02:45:49.7 |
HIP 67099 |
33.54 |
| 2026-10-05 12:00 |
13:45:04.23 |
-02:47:50.9 |
HIP 67099 |
31.10 |
| 2026-10-06 00:00 |
13:45:20.13 |
-02:49:52.0 |
HIP 67099 |
29.14 |
| 2026-10-06 12:00 |
13:45:36.06 |
-02:51:53.1 |
HIP 67099 |
27.77 |
| 2026-10-07 00:00 |
13:45:52.03 |
-02:53:54.0 |
HIP 67099 |
27.08 |
| 2026-10-07 12:00 |
13:46:08.02 |
-02:55:54.9 |
HIP 67099 |
27.12 |
| 2026-10-08 00:00 |
13:46:24.06 |
-02:57:55.7 |
HIP 67099 |
27.89 |
| 2026-10-08 12:00 |
13:46:40.12 |
-02:59:56.4 |
HIP 67099 |
29.34 |
| 2026-10-09 00:00 |
13:46:56.21 |
-03:01:57.0 |
HIP 67385 |
28.10 |
| 2026-10-09 12:00 |
13:47:12.33 |
-03:03:57.5 |
HIP 67385 |
25.49 |
| 2026-10-10 00:00 |
13:47:28.49 |
-03:05:57.8 |
HIP 67385 |
23.45 |
| 2026-10-10 12:00 |
13:47:44.67 |
-03:07:58.1 |
HIP 67385 |
22.15 |
| 2026-10-11 00:00 |
13:48:00.88 |
-03:09:58.2 |
HIP 67385 |
21.72 |