C/2015 R1 (PANSTARRS)
| Parameter |
Value |
| Designation |
C/2015 R1 (PANSTARRS) |
| Type |
C |
| 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) |
| 2026-02-03 00:00 |
13:55:57.72 |
+00:46:59.8 |
HIP 68086 |
8.49 |
| 2026-02-03 12:00 |
13:55:57.55 |
+00:47:29.6 |
HIP 68086 |
8.26 |
| 2026-02-04 00:00 |
13:55:57.25 |
+00:48:00.0 |
HIP 68086 |
8.08 |
| 2026-02-04 12:00 |
13:55:56.82 |
+00:48:30.9 |
HIP 68086 |
7.96 |
| 2026-02-05 00:00 |
13:55:56.26 |
+00:49:02.6 |
HIP 68086 |
7.89 |
| 2026-02-05 12:00 |
13:55:55.58 |
+00:49:34.9 |
HIP 68086 |
7.89 |
| 2026-02-06 00:00 |
13:55:54.77 |
+00:50:07.8 |
HIP 68086 |
7.95 |
| 2026-02-06 12:00 |
13:55:53.84 |
+00:50:41.4 |
HIP 68086 |
8.09 |
| 2026-02-07 00:00 |
13:55:52.77 |
+00:51:15.6 |
HIP 68086 |
8.31 |
| 2026-02-07 12:00 |
13:55:51.58 |
+00:51:50.5 |
HIP 68086 |
8.59 |
| 2026-02-08 00:00 |
13:55:50.27 |
+00:52:26.0 |
HIP 68086 |
8.95 |
| 2026-02-08 12:00 |
13:55:48.82 |
+00:53:02.1 |
HIP 68086 |
9.37 |
| 2026-02-09 00:00 |
13:55:47.25 |
+00:53:38.8 |
HIP 68086 |
9.86 |
| 2026-02-09 12:00 |
13:55:45.55 |
+00:54:16.2 |
HIP 68086 |
10.42 |
| 2026-02-10 00:00 |
13:55:43.72 |
+00:54:54.1 |
HIP 68086 |
11.03 |
| 2026-02-10 12:00 |
13:55:41.76 |
+00:55:32.7 |
HIP 68086 |
11.69 |
| 2026-02-11 00:00 |
13:55:39.67 |
+00:56:11.9 |
HIP 68086 |
12.40 |
| 2026-02-11 12:00 |
13:55:37.46 |
+00:56:51.6 |
HIP 68086 |
13.17 |
| 2026-02-12 00:00 |
13:55:35.11 |
+00:57:32.0 |
HIP 68086 |
13.97 |
| 2026-02-12 12:00 |
13:55:32.64 |
+00:58:13.0 |
HIP 68092 |
14.63 |
| 2026-02-13 00:00 |
13:55:30.04 |
+00:58:54.5 |
HIP 68092 |
15.04 |
| 2026-02-13 12:00 |
13:55:27.31 |
+00:59:36.7 |
HIP 68092 |
15.52 |
| 2026-02-14 00:00 |
13:55:24.46 |
+01:00:19.4 |
HIP 68092 |
16.09 |
| 2026-02-14 12:00 |
13:55:21.47 |
+01:01:02.7 |
HIP 68092 |
16.72 |
| 2026-02-15 00:00 |
13:55:18.36 |
+01:01:46.5 |
HIP 68092 |
17.43 |
| 2026-02-15 12:00 |
13:55:15.11 |
+01:02:31.0 |
HIP 68092 |
18.20 |
| 2026-02-16 00:00 |
13:55:11.74 |
+01:03:15.9 |
HIP 68092 |
19.04 |
| 2026-02-16 12:00 |
13:55:08.25 |
+01:04:01.5 |
HIP 68092 |
19.93 |
| 2026-02-17 00:00 |
13:55:04.62 |
+01:04:47.5 |
HIP 68092 |
20.89 |
| 2026-02-17 12:00 |
13:55:00.87 |
+01:05:34.1 |
HIP 68092 |
21.90 |
| 2026-02-18 00:00 |
13:54:56.98 |
+01:06:21.3 |
HIP 67828 |
22.33 |
| 2026-02-18 12:00 |
13:54:52.98 |
+01:07:09.0 |
HIP 67828 |
21.89 |
| 2026-02-19 00:00 |
13:54:48.84 |
+01:07:57.1 |
HIP 67828 |
21.50 |
| 2026-02-19 12:00 |
13:54:44.58 |
+01:08:45.8 |
HIP 67828 |
21.17 |
| 2026-02-20 00:00 |
13:54:40.19 |
+01:09:35.1 |
HIP 67828 |
20.89 |
| 2026-02-20 12:00 |
13:54:35.67 |
+01:10:24.8 |
HIP 67828 |
20.70 |
| 2026-02-21 00:00 |
13:54:31.03 |
+01:11:15.0 |
HIP 67828 |
20.58 |
| 2026-02-21 12:00 |
13:54:26.26 |
+01:12:05.7 |
HIP 67828 |
20.55 |
| 2026-02-22 00:00 |
13:54:21.37 |
+01:12:56.8 |
HIP 67828 |
20.61 |
| 2026-02-22 12:00 |
13:54:16.36 |
+01:13:48.5 |
HIP 67828 |
20.77 |
| 2026-02-23 00:00 |
13:54:11.22 |
+01:14:40.6 |
HIP 67828 |
21.04 |
| 2026-02-23 12:00 |
13:54:05.95 |
+01:15:33.1 |
HIP 67828 |
21.42 |
| 2026-02-24 00:00 |
13:54:00.57 |
+01:16:26.1 |
HIP 67828 |
21.90 |