| 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
$$
M_a = (6.637 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.637 |
| n |
6.000 |
| gf |
0.948 |
| gb |
-0.640 |
| k |
0.800 |
| δ90 |
8.992 |
| 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) |
| 2026-03-26 00:00 |
16:37:55.75 |
+10:41:14.8 |
HIP 81341 |
17.35 |
| 2026-03-26 12:00 |
16:37:54.12 |
+10:42:11.6 |
HIP 81341 |
16.86 |
| 2026-03-27 00:00 |
16:37:52.42 |
+10:43:08.3 |
HIP 81341 |
16.42 |
| 2026-03-27 12:00 |
16:37:50.67 |
+10:44:05.0 |
HIP 81341 |
16.01 |
| 2026-03-28 00:00 |
16:37:48.87 |
+10:45:01.5 |
HIP 81341 |
15.65 |
| 2026-03-28 12:00 |
16:37:47.00 |
+10:45:58.0 |
HIP 81341 |
15.33 |
| 2026-03-29 00:00 |
16:37:45.08 |
+10:46:54.3 |
HIP 81341 |
15.07 |
| 2026-03-29 12:00 |
16:37:43.10 |
+10:47:50.6 |
HIP 81341 |
14.86 |
| 2026-03-30 00:00 |
16:37:41.07 |
+10:48:46.8 |
HIP 81341 |
14.71 |
| 2026-03-30 12:00 |
16:37:38.97 |
+10:49:42.8 |
HIP 81341 |
14.63 |
| 2026-03-31 00:00 |
16:37:36.83 |
+10:50:38.8 |
HIP 81341 |
14.61 |
| 2026-03-31 12:00 |
16:37:34.62 |
+10:51:34.6 |
HIP 81341 |
14.66 |
| 2026-04-01 00:00 |
16:37:32.36 |
+10:52:30.3 |
HIP 81341 |
14.77 |
| 2026-04-01 12:00 |
16:37:30.04 |
+10:53:25.9 |
HIP 81341 |
14.95 |
| 2026-04-02 00:00 |
16:37:27.67 |
+10:54:21.3 |
HIP 81341 |
15.19 |
| 2026-04-02 12:00 |
16:37:25.25 |
+10:55:16.7 |
HIP 81341 |
15.50 |
| 2026-04-03 00:00 |
16:37:22.76 |
+10:56:11.9 |
HIP 81341 |
15.86 |
| 2026-04-03 12:00 |
16:37:20.23 |
+10:57:06.9 |
HIP 81341 |
16.29 |
| 2026-04-04 00:00 |
16:37:17.64 |
+10:58:01.8 |
HIP 81341 |
16.77 |
| 2026-04-04 12:00 |
16:37:14.99 |
+10:58:56.5 |
HIP 81341 |
17.30 |
| 2026-04-05 00:00 |
16:37:12.29 |
+10:59:51.1 |
HIP 81341 |
17.87 |
| 2026-04-05 12:00 |
16:37:09.54 |
+11:00:45.5 |
HIP 81341 |
18.50 |
| 2026-04-06 00:00 |
16:37:06.73 |
+11:01:39.8 |
HIP 81341 |
19.16 |
| 2026-04-06 12:00 |
16:37:03.87 |
+11:02:33.9 |
HIP 81341 |
19.86 |
| 2026-04-07 00:00 |
16:37:00.96 |
+11:03:27.8 |
HIP 81341 |
20.59 |
| 2026-04-07 12:00 |
16:36:57.99 |
+11:04:21.6 |
HIP 81341 |
21.35 |
| 2026-04-08 00:00 |
16:36:54.98 |
+11:05:15.1 |
HIP 81341 |
22.15 |
| 2026-04-08 12:00 |
16:36:51.91 |
+11:06:08.5 |
HIP 81341 |
22.97 |
| 2026-04-09 00:00 |
16:36:48.78 |
+11:07:01.7 |
HIP 81341 |
23.82 |
| 2026-04-09 12:00 |
16:36:45.61 |
+11:07:54.6 |
HIP 81341 |
24.69 |
| 2026-04-10 00:00 |
16:36:42.38 |
+11:08:47.4 |
HIP 81341 |
25.58 |
| 2026-04-10 12:00 |
16:36:39.11 |
+11:09:40.0 |
HIP 81341 |
26.49 |
| 2026-04-11 00:00 |
16:36:35.78 |
+11:10:32.3 |
HIP 81341 |
27.42 |
| 2026-04-11 12:00 |
16:36:32.40 |
+11:11:24.5 |
HIP 81175 |
28.13 |
| 2026-04-12 00:00 |
16:36:28.98 |
+11:12:16.4 |
HIP 81175 |
26.99 |
| 2026-04-12 12:00 |
16:36:25.50 |
+11:13:08.1 |
HIP 81175 |
25.85 |
| 2026-04-13 00:00 |
16:36:21.97 |
+11:13:59.5 |
HIP 81175 |
24.71 |
| 2026-04-13 12:00 |
16:36:18.40 |
+11:14:50.7 |
HIP 81175 |
23.56 |
| 2026-04-14 00:00 |
16:36:14.77 |
+11:15:41.7 |
HIP 81175 |
22.42 |
| 2026-04-14 12:00 |
16:36:11.10 |
+11:16:32.5 |
HIP 81175 |
21.27 |
| 2026-04-15 00:00 |
16:36:07.38 |
+11:17:22.9 |
HIP 81175 |
20.13 |
| 2026-04-15 12:00 |
16:36:03.61 |
+11:18:13.2 |
HIP 81175 |
18.98 |
| 2026-04-16 00:00 |
16:35:59.80 |
+11:19:03.1 |
HIP 81175 |
17.84 |