C/2015 H2 (PANSTARRS)
| 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) |
| 2026-02-03 00:00 |
01:20:14.11 |
+35:27:09.5 |
HIP 6255 |
19.83 |
| 2026-02-03 12:00 |
01:20:17.22 |
+35:26:54.3 |
HIP 6255 |
19.59 |
| 2026-02-04 00:00 |
01:20:20.39 |
+35:26:39.4 |
HIP 6255 |
19.37 |
| 2026-02-04 12:00 |
01:20:23.60 |
+35:26:24.9 |
HIP 6255 |
19.18 |
| 2026-02-05 00:00 |
01:20:26.86 |
+35:26:10.7 |
HIP 6255 |
19.03 |
| 2026-02-05 12:00 |
01:20:30.16 |
+35:25:57.0 |
HIP 6255 |
18.91 |
| 2026-02-06 00:00 |
01:20:33.52 |
+35:25:43.5 |
HIP 6255 |
18.82 |
| 2026-02-06 12:00 |
01:20:36.92 |
+35:25:30.5 |
HIP 6255 |
18.77 |
| 2026-02-07 00:00 |
01:20:40.36 |
+35:25:17.8 |
HIP 6255 |
18.75 |
| 2026-02-07 12:00 |
01:20:43.86 |
+35:25:05.5 |
HIP 6255 |
18.77 |
| 2026-02-08 00:00 |
01:20:47.40 |
+35:24:53.5 |
HIP 6255 |
18.83 |
| 2026-02-08 12:00 |
01:20:50.98 |
+35:24:42.0 |
HIP 6255 |
18.93 |
| 2026-02-09 00:00 |
01:20:54.61 |
+35:24:30.8 |
HIP 6255 |
19.07 |
| 2026-02-09 12:00 |
01:20:58.29 |
+35:24:19.9 |
HIP 6255 |
19.25 |
| 2026-02-10 00:00 |
01:21:02.01 |
+35:24:09.5 |
HIP 6255 |
19.47 |
| 2026-02-10 12:00 |
01:21:05.78 |
+35:23:59.4 |
HIP 6255 |
19.72 |
| 2026-02-11 00:00 |
01:21:09.59 |
+35:23:49.6 |
HIP 6255 |
20.01 |
| 2026-02-11 12:00 |
01:21:13.44 |
+35:23:40.3 |
HIP 6255 |
20.35 |
| 2026-02-12 00:00 |
01:21:17.34 |
+35:23:31.3 |
HIP 6255 |
20.71 |
| 2026-02-12 12:00 |
01:21:21.28 |
+35:23:22.7 |
HIP 6255 |
21.11 |
| 2026-02-13 00:00 |
01:21:25.27 |
+35:23:14.5 |
HIP 6255 |
21.55 |
| 2026-02-13 12:00 |
01:21:29.30 |
+35:23:06.7 |
HIP 6255 |
22.02 |
| 2026-02-14 00:00 |
01:21:33.37 |
+35:22:59.2 |
HIP 6255 |
22.52 |
| 2026-02-14 12:00 |
01:21:37.49 |
+35:22:52.2 |
HIP 6255 |
23.05 |
| 2026-02-15 00:00 |
01:21:41.64 |
+35:22:45.5 |
HIP 6255 |
23.61 |
| 2026-02-15 12:00 |
01:21:45.84 |
+35:22:39.2 |
HIP 6255 |
24.20 |
| 2026-02-16 00:00 |
01:21:50.08 |
+35:22:33.2 |
HIP 6255 |
24.82 |
| 2026-02-16 12:00 |
01:21:54.37 |
+35:22:27.7 |
HIP 6255 |
25.46 |
| 2026-02-17 00:00 |
01:21:58.69 |
+35:22:22.5 |
HIP 6255 |
26.12 |
| 2026-02-17 12:00 |
01:22:03.05 |
+35:22:17.7 |
HIP 6255 |
26.81 |
| 2026-02-18 00:00 |
01:22:07.46 |
+35:22:13.3 |
HIP 6255 |
27.52 |
| 2026-02-18 12:00 |
01:22:11.90 |
+35:22:09.3 |
HIP 6255 |
28.26 |
| 2026-02-19 00:00 |
01:22:16.39 |
+35:22:05.6 |
HIP 6255 |
29.01 |
| 2026-02-19 12:00 |
01:22:20.91 |
+35:22:02.3 |
HIP 6255 |
29.78 |
| 2026-02-20 00:00 |
01:22:25.47 |
+35:21:59.5 |
HIP 6255 |
30.57 |
| 2026-02-20 12:00 |
01:22:30.08 |
+35:21:57.0 |
HIP 6255 |
31.38 |
| 2026-02-21 00:00 |
01:22:34.72 |
+35:21:54.8 |
HIP 6255 |
32.21 |
| 2026-02-21 12:00 |
01:22:39.39 |
+35:21:53.1 |
HIP 6255 |
33.05 |
| 2026-02-22 00:00 |
01:22:44.11 |
+35:21:51.8 |
HIP 6255 |
33.90 |
| 2026-02-22 12:00 |
01:22:48.86 |
+35:21:50.8 |
HIP 6255 |
34.78 |
| 2026-02-23 00:00 |
01:22:53.65 |
+35:21:50.2 |
HIP 6636 |
35.23 |
| 2026-02-23 12:00 |
01:22:58.48 |
+35:21:50.0 |
HIP 6636 |
34.47 |
| 2026-02-24 00:00 |
01:23:03.34 |
+35:21:50.1 |
HIP 6636 |
33.72 |