| Parameter |
Value |
| Designation |
C/2015 H2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-09-13T06:35:06.138240Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:09Z |
| Obs used |
204 |
| NEO |
- |
| M1 |
11.300 |
| K1 |
5.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-02-24.0000000 |
| e |
1.00351211 |
| q (au) |
4.967122 |
| a (au) |
-1414.285460 |
| i (deg) |
33.705314 |
| Ω (om, deg) |
350.691893 |
| ω (w, deg) |
287.907632 |
| M (ma, deg) |
0.003034 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.029 + 2.136\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.029 |
| n |
2.136 |
| gf |
0.974 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
9.982 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2014-05-19 |
2016-09-08 |
+6.5323 |
-4.790 |
| 2016-11-03 |
2019-10-22 |
+0.0641 |
-0.234 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
01:28:48.24 |
+35:33:14.7 |
HIP 6903 |
13.13 |
| 2026-03-26 12:00 |
01:28:54.65 |
+35:33:36.9 |
HIP 6903 |
12.73 |
| 2026-03-27 00:00 |
01:29:01.07 |
+35:33:59.3 |
HIP 6903 |
12.46 |
| 2026-03-27 12:00 |
01:29:07.51 |
+35:34:22.1 |
HIP 6903 |
12.33 |
| 2026-03-28 00:00 |
01:29:13.96 |
+35:34:45.2 |
HIP 6903 |
12.35 |
| 2026-03-28 12:00 |
01:29:20.43 |
+35:35:08.7 |
HIP 6903 |
12.51 |
| 2026-03-29 00:00 |
01:29:26.90 |
+35:35:32.4 |
HIP 6903 |
12.81 |
| 2026-03-29 12:00 |
01:29:33.39 |
+35:35:56.5 |
HIP 6903 |
13.25 |
| 2026-03-30 00:00 |
01:29:39.89 |
+35:36:20.9 |
HIP 6903 |
13.81 |
| 2026-03-30 12:00 |
01:29:46.40 |
+35:36:45.6 |
HIP 6903 |
14.48 |
| 2026-03-31 00:00 |
01:29:52.93 |
+35:37:10.7 |
HIP 6903 |
15.24 |
| 2026-03-31 12:00 |
01:29:59.46 |
+35:37:36.0 |
HIP 6903 |
16.08 |
| 2026-04-01 00:00 |
01:30:06.00 |
+35:38:01.6 |
HIP 6903 |
17.00 |
| 2026-04-01 12:00 |
01:30:12.55 |
+35:38:27.6 |
HIP 6903 |
17.98 |
| 2026-04-02 00:00 |
01:30:19.12 |
+35:38:53.9 |
HIP 6903 |
19.01 |
| 2026-04-02 12:00 |
01:30:25.69 |
+35:39:20.4 |
HIP 6903 |
20.08 |
| 2026-04-03 00:00 |
01:30:32.27 |
+35:39:47.3 |
HIP 6903 |
21.20 |
| 2026-04-03 12:00 |
01:30:38.86 |
+35:40:14.5 |
HIP 6903 |
22.34 |
| 2026-04-04 00:00 |
01:30:45.46 |
+35:40:42.0 |
HIP 6903 |
23.52 |
| 2026-04-04 12:00 |
01:30:52.06 |
+35:41:09.8 |
HIP 6903 |
24.72 |
| 2026-04-05 00:00 |
01:30:58.67 |
+35:41:37.9 |
HIP 7201 |
23.86 |
| 2026-04-05 12:00 |
01:31:05.29 |
+35:42:06.3 |
HIP 7201 |
22.43 |
| 2026-04-06 00:00 |
01:31:11.92 |
+35:42:34.9 |
HIP 7201 |
21.01 |
| 2026-04-06 12:00 |
01:31:18.55 |
+35:43:03.9 |
HIP 7201 |
19.58 |
| 2026-04-07 00:00 |
01:31:25.19 |
+35:43:33.2 |
HIP 7201 |
18.15 |
| 2026-04-07 12:00 |
01:31:31.84 |
+35:44:02.8 |
HIP 7201 |
16.71 |
| 2026-04-08 00:00 |
01:31:38.49 |
+35:44:32.6 |
HIP 7201 |
15.28 |
| 2026-04-08 12:00 |
01:31:45.14 |
+35:45:02.8 |
HIP 7201 |
13.84 |
| 2026-04-09 00:00 |
01:31:51.80 |
+35:45:33.2 |
HIP 7201 |
12.40 |
| 2026-04-09 12:00 |
01:31:58.47 |
+35:46:03.9 |
HIP 7201 |
10.95 |
| 2026-04-10 00:00 |
01:32:05.14 |
+35:46:34.9 |
HIP 7201 |
9.51 |
| 2026-04-10 12:00 |
01:32:11.81 |
+35:47:06.2 |
HIP 7201 |
8.06 |
| 2026-04-11 00:00 |
01:32:18.48 |
+35:47:37.8 |
HIP 7201 |
6.61 |
| 2026-04-11 12:00 |
01:32:25.16 |
+35:48:09.6 |
HIP 7201 |
5.17 |
| 2026-04-12 00:00 |
01:32:31.84 |
+35:48:41.8 |
HIP 7201 |
3.72 |
| 2026-04-12 12:00 |
01:32:38.53 |
+35:49:14.2 |
HIP 7201 |
2.29 |
| 2026-04-13 00:00 |
01:32:45.21 |
+35:49:46.9 |
HIP 7201 |
0.94 |
| 2026-04-13 12:00 |
01:32:51.90 |
+35:50:19.8 |
HIP 7201 |
0.88 |
| 2026-04-14 00:00 |
01:32:58.59 |
+35:50:53.1 |
HIP 7201 |
2.23 |
| 2026-04-14 12:00 |
01:33:05.27 |
+35:51:26.6 |
HIP 7201 |
3.66 |
| 2026-04-15 00:00 |
01:33:11.96 |
+35:52:00.3 |
HIP 7201 |
5.12 |
| 2026-04-15 12:00 |
01:33:18.65 |
+35:52:34.4 |
HIP 7201 |
6.58 |
| 2026-04-16 00:00 |
01:33:25.34 |
+35:53:08.7 |
HIP 7201 |
8.05 |