| Parameter |
Value |
| Designation |
C/2015 T4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-06-18T22:43:23.779200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:15Z |
| Obs used |
345 |
| NEO |
- |
| M1 |
7.100 |
| K1 |
16.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-12-16.0000000 |
| e |
0.97361730 |
| q (au) |
2.296377 |
| a (au) |
87.040989 |
| i (deg) |
87.917192 |
| Ω (om, deg) |
251.787616 |
| ω (w, deg) |
270.135756 |
| M (ma, deg) |
359.774313 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.288 + 5.229\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.288 |
| n |
5.229 |
| gf |
0.992 |
| gb |
-1.000 |
| k |
0.999 |
| δ90 |
9.995 |
| 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 |
17:08:10.84 |
+33:11:09.0 |
HIP 83899 |
8.23 |
| 2026-09-20 12:00 |
17:08:11.99 |
+33:10:14.1 |
HIP 83899 |
8.25 |
| 2026-09-21 00:00 |
17:08:13.19 |
+33:09:19.2 |
HIP 83899 |
8.37 |
| 2026-09-21 12:00 |
17:08:14.45 |
+33:08:24.5 |
HIP 83899 |
8.58 |
| 2026-09-22 00:00 |
17:08:15.75 |
+33:07:29.9 |
HIP 83899 |
8.88 |
| 2026-09-22 12:00 |
17:08:17.09 |
+33:06:35.3 |
HIP 83899 |
9.25 |
| 2026-09-23 00:00 |
17:08:18.49 |
+33:05:40.9 |
HIP 83899 |
9.70 |
| 2026-09-23 12:00 |
17:08:19.94 |
+33:04:46.5 |
HIP 83899 |
10.22 |
| 2026-09-24 00:00 |
17:08:21.43 |
+33:03:52.3 |
HIP 83899 |
10.78 |
| 2026-09-24 12:00 |
17:08:22.97 |
+33:02:58.2 |
HIP 83899 |
11.39 |
| 2026-09-25 00:00 |
17:08:24.56 |
+33:02:04.2 |
HIP 83899 |
12.04 |
| 2026-09-25 12:00 |
17:08:26.19 |
+33:01:10.3 |
HIP 83899 |
12.72 |
| 2026-09-26 00:00 |
17:08:27.88 |
+33:00:16.6 |
HIP 83899 |
13.44 |
| 2026-09-26 12:00 |
17:08:29.61 |
+32:59:22.9 |
HIP 83899 |
14.17 |
| 2026-09-27 00:00 |
17:08:31.39 |
+32:58:29.4 |
HIP 83899 |
14.93 |
| 2026-09-27 12:00 |
17:08:33.21 |
+32:57:36.1 |
HIP 83899 |
15.71 |
| 2026-09-28 00:00 |
17:08:35.08 |
+32:56:42.9 |
HIP 83899 |
16.50 |
| 2026-09-28 12:00 |
17:08:37.00 |
+32:55:49.8 |
HIP 83899 |
17.31 |
| 2026-09-29 00:00 |
17:08:38.96 |
+32:54:56.9 |
HIP 83899 |
18.12 |
| 2026-09-29 12:00 |
17:08:40.97 |
+32:54:04.1 |
HIP 83899 |
18.96 |
| 2026-09-30 00:00 |
17:08:43.03 |
+32:53:11.5 |
HIP 83899 |
19.80 |
| 2026-09-30 12:00 |
17:08:45.13 |
+32:52:19.1 |
HIP 83899 |
20.64 |
| 2026-10-01 00:00 |
17:08:47.28 |
+32:51:26.8 |
HIP 83899 |
21.50 |
| 2026-10-01 12:00 |
17:08:49.47 |
+32:50:34.7 |
HIP 83899 |
22.37 |
| 2026-10-02 00:00 |
17:08:51.71 |
+32:49:42.7 |
HIP 83899 |
23.24 |
| 2026-10-02 12:00 |
17:08:54.00 |
+32:48:50.9 |
HIP 83899 |
24.12 |
| 2026-10-03 00:00 |
17:08:56.33 |
+32:47:59.4 |
HIP 83899 |
25.00 |
| 2026-10-03 12:00 |
17:08:58.70 |
+32:47:07.9 |
HIP 83899 |
25.89 |
| 2026-10-04 00:00 |
17:09:01.12 |
+32:46:16.7 |
HIP 83899 |
26.78 |
| 2026-10-04 12:00 |
17:09:03.59 |
+32:45:25.7 |
HIP 83899 |
27.68 |
| 2026-10-05 00:00 |
17:09:06.10 |
+32:44:34.8 |
HIP 83899 |
28.58 |
| 2026-10-05 12:00 |
17:09:08.65 |
+32:43:44.2 |
HIP 83899 |
29.49 |
| 2026-10-06 00:00 |
17:09:11.25 |
+32:42:53.8 |
HIP 83899 |
30.40 |
| 2026-10-06 12:00 |
17:09:13.90 |
+32:42:03.5 |
HIP 83899 |
31.32 |
| 2026-10-07 00:00 |
17:09:16.58 |
+32:41:13.5 |
HIP 84089 |
31.51 |
| 2026-10-07 12:00 |
17:09:19.31 |
+32:40:23.7 |
HIP 84089 |
31.41 |
| 2026-10-08 00:00 |
17:09:22.09 |
+32:39:34.1 |
HIP 84089 |
31.35 |
| 2026-10-08 12:00 |
17:09:24.90 |
+32:38:44.8 |
HIP 84089 |
31.30 |
| 2026-10-09 00:00 |
17:09:27.76 |
+32:37:55.6 |
HIP 84089 |
31.28 |
| 2026-10-09 12:00 |
17:09:30.67 |
+32:37:06.8 |
HIP 84040 |
31.03 |
| 2026-10-10 00:00 |
17:09:33.61 |
+32:36:18.1 |
HIP 84040 |
30.02 |
| 2026-10-10 12:00 |
17:09:36.60 |
+32:35:29.7 |
HIP 84040 |
29.00 |
| 2026-10-11 00:00 |
17:09:39.63 |
+32:34:41.5 |
HIP 84040 |
27.98 |