| Parameter |
Value |
| Designation |
C/2015 D2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-09-27T14:47:50.671680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:07Z |
| Obs used |
68 |
| NEO |
- |
| M1 |
7.100 |
| K1 |
12.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-03-24.0000000 |
| e |
0.56825603 |
| q (au) |
5.606049 |
| a (au) |
12.984662 |
| i (deg) |
31.834348 |
| Ω (om, deg) |
162.858947 |
| ω (w, deg) |
291.923116 |
| M (ma, deg) |
11.425219 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.640 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.640 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.639 |
| k |
0.800 |
| δ90 |
9.439 |
| 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 |
16:18:53.39 |
+11:33:18.2 |
HIP 79989 |
22.37 |
| 2026-07-29 12:00 |
16:18:51.12 |
+11:32:34.8 |
HIP 79989 |
22.05 |
| 2026-07-30 00:00 |
16:18:48.91 |
+11:31:51.2 |
HIP 79989 |
21.76 |
| 2026-07-30 12:00 |
16:18:46.74 |
+11:31:07.2 |
HIP 79989 |
21.49 |
| 2026-07-31 00:00 |
16:18:44.64 |
+11:30:22.9 |
HIP 79989 |
21.24 |
| 2026-07-31 12:00 |
16:18:42.58 |
+11:29:38.3 |
HIP 79989 |
21.02 |
| 2026-08-01 00:00 |
16:18:40.58 |
+11:28:53.4 |
HIP 79989 |
20.82 |
| 2026-08-01 12:00 |
16:18:38.63 |
+11:28:08.2 |
HIP 79989 |
20.64 |
| 2026-08-02 00:00 |
16:18:36.74 |
+11:27:22.7 |
HIP 79989 |
20.49 |
| 2026-08-02 12:00 |
16:18:34.90 |
+11:26:36.9 |
HIP 79989 |
20.36 |
| 2026-08-03 00:00 |
16:18:33.12 |
+11:25:50.9 |
HIP 79989 |
20.26 |
| 2026-08-03 12:00 |
16:18:31.39 |
+11:25:04.5 |
HIP 79989 |
20.18 |
| 2026-08-04 00:00 |
16:18:29.71 |
+11:24:17.9 |
HIP 79989 |
20.12 |
| 2026-08-04 12:00 |
16:18:28.09 |
+11:23:31.0 |
HIP 79989 |
20.09 |
| 2026-08-05 00:00 |
16:18:26.52 |
+11:22:43.8 |
HIP 79989 |
20.08 |
| 2026-08-05 12:00 |
16:18:25.01 |
+11:21:56.3 |
HIP 79989 |
20.10 |
| 2026-08-06 00:00 |
16:18:23.56 |
+11:21:08.6 |
HIP 79989 |
20.14 |
| 2026-08-06 12:00 |
16:18:22.16 |
+11:20:20.6 |
HIP 79989 |
20.20 |
| 2026-08-07 00:00 |
16:18:20.82 |
+11:19:32.3 |
HIP 79989 |
20.29 |
| 2026-08-07 12:00 |
16:18:19.53 |
+11:18:43.8 |
HIP 79989 |
20.40 |
| 2026-08-08 00:00 |
16:18:18.30 |
+11:17:55.1 |
HIP 79989 |
20.53 |
| 2026-08-08 12:00 |
16:18:17.12 |
+11:17:06.1 |
HIP 79989 |
20.68 |
| 2026-08-09 00:00 |
16:18:16.00 |
+11:16:16.8 |
HIP 79989 |
20.85 |
| 2026-08-09 12:00 |
16:18:14.94 |
+11:15:27.3 |
HIP 79989 |
21.05 |
| 2026-08-10 00:00 |
16:18:13.93 |
+11:14:37.6 |
HIP 79989 |
21.26 |
| 2026-08-10 12:00 |
16:18:12.99 |
+11:13:47.6 |
HIP 79989 |
21.49 |
| 2026-08-11 00:00 |
16:18:12.09 |
+11:12:57.4 |
HIP 79989 |
21.74 |
| 2026-08-11 12:00 |
16:18:11.26 |
+11:12:07.0 |
HIP 79989 |
22.01 |
| 2026-08-12 00:00 |
16:18:10.48 |
+11:11:16.3 |
HIP 79989 |
22.29 |
| 2026-08-12 12:00 |
16:18:09.76 |
+11:10:25.4 |
HIP 79989 |
22.59 |
| 2026-08-13 00:00 |
16:18:09.09 |
+11:09:34.3 |
HIP 79989 |
22.91 |
| 2026-08-13 12:00 |
16:18:08.49 |
+11:08:43.1 |
HIP 79989 |
23.24 |
| 2026-08-14 00:00 |
16:18:07.94 |
+11:07:51.6 |
HIP 79989 |
23.59 |
| 2026-08-14 12:00 |
16:18:07.45 |
+11:06:59.9 |
HIP 79989 |
23.95 |
| 2026-08-15 00:00 |
16:18:07.01 |
+11:06:08.0 |
HIP 79989 |
24.32 |
| 2026-08-15 12:00 |
16:18:06.64 |
+11:05:15.9 |
HIP 79989 |
24.71 |
| 2026-08-16 00:00 |
16:18:06.32 |
+11:04:23.6 |
HIP 79989 |
25.11 |
| 2026-08-16 12:00 |
16:18:06.06 |
+11:03:31.1 |
HIP 79989 |
25.52 |
| 2026-08-17 00:00 |
16:18:05.85 |
+11:02:38.5 |
HIP 79989 |
25.94 |
| 2026-08-17 12:00 |
16:18:05.71 |
+11:01:45.7 |
HIP 79989 |
26.38 |
| 2026-08-18 00:00 |
16:18:05.62 |
+11:00:52.7 |
HIP 79989 |
26.82 |
| 2026-08-18 12:00 |
16:18:05.59 |
+10:59:59.5 |
HIP 79989 |
27.28 |
| 2026-08-19 00:00 |
16:18:05.62 |
+10:59:06.2 |
HIP 79989 |
27.75 |