| Parameter |
Value |
| Designation |
C/2013 G8 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-11-14T23:30:02.741760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:34Z |
| Obs used |
147 |
| NEO |
- |
| M1 |
7.700 |
| K1 |
11.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-09-14.0000000 |
| e |
0.99844886 |
| q (au) |
5.141176 |
| a (au) |
3314.451067 |
| i (deg) |
27.615046 |
| Ω (om, deg) |
241.021944 |
| ω (w, deg) |
80.168493 |
| M (ma, deg) |
359.999680 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.524 + 2.882\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.524 |
| n |
2.882 |
| gf |
1.000 |
| gb |
-0.652 |
| k |
0.800 |
| δ90 |
10.000 |
| 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) |
| 2026-05-12 00:00 |
05:38:07.68 |
+11:21:05.4 |
HIP 26618 |
21.57 |
| 2026-05-12 12:00 |
05:38:11.86 |
+11:21:11.8 |
HIP 26618 |
20.60 |
| 2026-05-13 00:00 |
05:38:16.07 |
+11:21:18.2 |
HIP 26618 |
19.63 |
| 2026-05-13 12:00 |
05:38:20.30 |
+11:21:24.4 |
HIP 26618 |
18.66 |
| 2026-05-14 00:00 |
05:38:24.54 |
+11:21:30.6 |
HIP 26618 |
17.70 |
| 2026-05-14 12:00 |
05:38:28.81 |
+11:21:36.7 |
HIP 26618 |
16.74 |
| 2026-05-15 00:00 |
05:38:33.09 |
+11:21:42.6 |
HIP 26618 |
15.80 |
| 2026-05-15 12:00 |
05:38:37.39 |
+11:21:48.5 |
HIP 26618 |
14.86 |
| 2026-05-16 00:00 |
05:38:41.71 |
+11:21:54.3 |
HIP 26618 |
13.95 |
| 2026-05-16 12:00 |
05:38:46.04 |
+11:22:00.0 |
HIP 26618 |
13.05 |
| 2026-05-17 00:00 |
05:38:50.39 |
+11:22:05.6 |
HIP 26618 |
12.17 |
| 2026-05-17 12:00 |
05:38:54.76 |
+11:22:11.1 |
HIP 26618 |
11.33 |
| 2026-05-18 00:00 |
05:38:59.14 |
+11:22:16.5 |
HIP 26618 |
10.53 |
| 2026-05-18 12:00 |
05:39:03.54 |
+11:22:21.8 |
HIP 26618 |
9.78 |
| 2026-05-19 00:00 |
05:39:07.96 |
+11:22:26.9 |
HIP 26618 |
9.10 |
| 2026-05-19 12:00 |
05:39:12.39 |
+11:22:32.0 |
HIP 26618 |
8.50 |
| 2026-05-20 00:00 |
05:39:16.84 |
+11:22:37.0 |
HIP 26618 |
8.00 |
| 2026-05-20 12:00 |
05:39:21.30 |
+11:22:41.9 |
HIP 26618 |
7.63 |
| 2026-05-21 00:00 |
05:39:25.77 |
+11:22:46.7 |
HIP 26618 |
7.41 |
| 2026-05-21 12:00 |
05:39:30.26 |
+11:22:51.4 |
HIP 26618 |
7.35 |
| 2026-05-22 00:00 |
05:39:34.77 |
+11:22:56.0 |
HIP 26618 |
7.46 |
| 2026-05-22 12:00 |
05:39:39.28 |
+11:23:00.5 |
HIP 26618 |
7.73 |
| 2026-05-23 00:00 |
05:39:43.81 |
+11:23:04.8 |
HIP 26618 |
8.14 |
| 2026-05-23 12:00 |
05:39:48.36 |
+11:23:09.1 |
HIP 26618 |
8.69 |
| 2026-05-24 00:00 |
05:39:52.92 |
+11:23:13.3 |
HIP 26618 |
9.33 |
| 2026-05-24 12:00 |
05:39:57.49 |
+11:23:17.4 |
HIP 26618 |
10.07 |
| 2026-05-25 00:00 |
05:40:02.07 |
+11:23:21.3 |
HIP 26618 |
10.87 |
| 2026-05-25 12:00 |
05:40:06.66 |
+11:23:25.2 |
HIP 26618 |
11.73 |
| 2026-05-26 00:00 |
05:40:11.27 |
+11:23:28.9 |
HIP 26618 |
12.64 |
| 2026-05-26 12:00 |
05:40:15.88 |
+11:23:32.6 |
HIP 26669 |
13.30 |
| 2026-05-27 00:00 |
05:40:20.51 |
+11:23:36.1 |
HIP 26669 |
13.63 |
| 2026-05-27 12:00 |
05:40:25.15 |
+11:23:39.6 |
HIP 26669 |
14.06 |
| 2026-05-28 00:00 |
05:40:29.80 |
+11:23:42.9 |
HIP 26669 |
14.55 |
| 2026-05-28 12:00 |
05:40:34.46 |
+11:23:46.1 |
HIP 26669 |
15.12 |
| 2026-05-29 00:00 |
05:40:39.13 |
+11:23:49.2 |
HIP 26669 |
15.75 |
| 2026-05-29 12:00 |
05:40:43.81 |
+11:23:52.2 |
HIP 26669 |
16.44 |
| 2026-05-30 00:00 |
05:40:48.50 |
+11:23:55.1 |
HIP 26669 |
17.17 |
| 2026-05-30 12:00 |
05:40:53.20 |
+11:23:57.9 |
HIP 26669 |
17.95 |
| 2026-05-31 00:00 |
05:40:57.91 |
+11:24:00.6 |
HIP 26669 |
18.77 |
| 2026-05-31 12:00 |
05:41:02.63 |
+11:24:03.2 |
HIP 26669 |
19.62 |
| 2026-06-01 00:00 |
05:41:07.36 |
+11:24:05.7 |
HIP 26669 |
20.50 |
| 2026-06-01 12:00 |
05:41:12.09 |
+11:24:08.0 |
HIP 26669 |
21.41 |
| 2026-06-02 00:00 |
05:41:16.83 |
+11:24:10.3 |
HIP 26669 |
22.35 |