| 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) |
| 2026-07-29 00:00 |
17:10:52.08 |
+34:40:56.6 |
HIP 84242 |
30.54 |
| 2026-07-29 12:00 |
17:10:48.07 |
+34:40:18.0 |
HIP 84242 |
31.14 |
| 2026-07-30 00:00 |
17:10:44.10 |
+34:39:39.0 |
HIP 84242 |
31.74 |
| 2026-07-30 12:00 |
17:10:40.17 |
+34:38:59.7 |
HIP 84242 |
32.36 |
| 2026-07-31 00:00 |
17:10:36.29 |
+34:38:19.9 |
HIP 84242 |
32.99 |
| 2026-07-31 12:00 |
17:10:32.44 |
+34:37:39.9 |
HIP 84242 |
33.63 |
| 2026-08-01 00:00 |
17:10:28.64 |
+34:36:59.4 |
HIP 84242 |
34.28 |
| 2026-08-01 12:00 |
17:10:24.89 |
+34:36:18.6 |
HIP 83872 |
34.65 |
| 2026-08-02 00:00 |
17:10:21.17 |
+34:35:37.5 |
HIP 83872 |
34.67 |
| 2026-08-02 12:00 |
17:10:17.50 |
+34:34:55.9 |
HIP 83872 |
34.72 |
| 2026-08-03 00:00 |
17:10:13.87 |
+34:34:14.1 |
HIP 83872 |
34.82 |
| 2026-08-03 12:00 |
17:10:10.28 |
+34:33:31.9 |
HIP 83872 |
34.95 |
| 2026-08-04 00:00 |
17:10:06.74 |
+34:32:49.4 |
HIP 83872 |
35.12 |
| 2026-08-04 12:00 |
17:10:03.24 |
+34:32:06.5 |
HIP 83872 |
35.33 |
| 2026-08-05 00:00 |
17:09:59.79 |
+34:31:23.3 |
HIP 83872 |
35.58 |
| 2026-08-05 12:00 |
17:09:56.38 |
+34:30:39.7 |
HIP 83872 |
35.86 |
| 2026-08-06 00:00 |
17:09:53.01 |
+34:29:55.9 |
HIP 83872 |
36.18 |
| 2026-08-06 12:00 |
17:09:49.69 |
+34:29:11.7 |
HIP 83872 |
36.53 |
| 2026-08-07 00:00 |
17:09:46.42 |
+34:28:27.2 |
HIP 83872 |
36.91 |
| 2026-08-07 12:00 |
17:09:43.19 |
+34:27:42.4 |
HIP 83872 |
37.33 |
| 2026-08-08 00:00 |
17:09:40.01 |
+34:26:57.2 |
HIP 83872 |
37.77 |
| 2026-08-08 12:00 |
17:09:36.87 |
+34:26:11.8 |
HIP 83872 |
38.25 |
| 2026-08-09 00:00 |
17:09:33.78 |
+34:25:26.1 |
HIP 83872 |
38.75 |
| 2026-08-09 12:00 |
17:09:30.73 |
+34:24:40.0 |
HIP 83971 |
38.17 |
| 2026-08-10 00:00 |
17:09:27.73 |
+34:23:53.7 |
HIP 83971 |
37.48 |
| 2026-08-10 12:00 |
17:09:24.78 |
+34:23:07.1 |
HIP 83971 |
36.79 |
| 2026-08-11 00:00 |
17:09:21.88 |
+34:22:20.2 |
HIP 83971 |
36.11 |
| 2026-08-11 12:00 |
17:09:19.02 |
+34:21:33.0 |
HIP 83971 |
35.44 |
| 2026-08-12 00:00 |
17:09:16.21 |
+34:20:45.6 |
HIP 83971 |
34.78 |
| 2026-08-12 12:00 |
17:09:13.45 |
+34:19:57.8 |
HIP 83971 |
34.13 |
| 2026-08-13 00:00 |
17:09:10.73 |
+34:19:09.8 |
HIP 83971 |
33.48 |
| 2026-08-13 12:00 |
17:09:08.07 |
+34:18:21.6 |
HIP 83971 |
32.85 |
| 2026-08-14 00:00 |
17:09:05.45 |
+34:17:33.1 |
HIP 83971 |
32.22 |
| 2026-08-14 12:00 |
17:09:02.88 |
+34:16:44.3 |
HIP 83971 |
31.61 |
| 2026-08-15 00:00 |
17:09:00.36 |
+34:15:55.3 |
HIP 83971 |
31.01 |
| 2026-08-15 12:00 |
17:08:57.88 |
+34:15:06.0 |
HIP 83971 |
30.42 |
| 2026-08-16 00:00 |
17:08:55.46 |
+34:14:16.6 |
HIP 83971 |
29.84 |
| 2026-08-16 12:00 |
17:08:53.09 |
+34:13:26.8 |
HIP 83971 |
29.27 |
| 2026-08-17 00:00 |
17:08:50.76 |
+34:12:36.9 |
HIP 83971 |
28.72 |
| 2026-08-17 12:00 |
17:08:48.49 |
+34:11:46.7 |
HIP 83971 |
28.18 |
| 2026-08-18 00:00 |
17:08:46.26 |
+34:10:56.3 |
HIP 83971 |
27.66 |
| 2026-08-18 12:00 |
17:08:44.08 |
+34:10:05.7 |
HIP 83971 |
27.15 |
| 2026-08-19 00:00 |
17:08:41.95 |
+34:09:14.9 |
HIP 83971 |
26.66 |