| Parameter |
Value |
| Designation |
C/2013 E2 (Iwamoto) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-03-09T00:45:46.535040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:32Z |
| Obs used |
1159 |
| NEO |
- |
| M1 |
10.800 |
| K1 |
6.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-08-12.0000000 |
| e |
0.99393505 |
| q (au) |
1.413322 |
| a (au) |
233.031227 |
| i (deg) |
21.857721 |
| Ω (om, deg) |
182.470545 |
| ω (w, deg) |
95.823644 |
| M (ma, deg) |
0.043213 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.451 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.451 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.751 |
| k |
0.996 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2013-03-10 |
2013-06-03 |
+5.4065 |
-1.965 |
| 2013-06-03 |
2014-02-02 |
-0.2753 |
-0.072 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
04:54:05.27 |
+02:27:38.5 |
HIP 22797 |
2.73 |
| 2026-06-01 12:00 |
04:54:09.27 |
+02:27:46.0 |
HIP 22797 |
1.97 |
| 2026-06-02 00:00 |
04:54:13.27 |
+02:27:53.4 |
HIP 22797 |
1.52 |
| 2026-06-02 12:00 |
04:54:17.26 |
+02:28:00.6 |
HIP 22797 |
1.66 |
| 2026-06-03 00:00 |
04:54:21.26 |
+02:28:07.6 |
HIP 22797 |
2.28 |
| 2026-06-03 12:00 |
04:54:25.27 |
+02:28:14.5 |
HIP 22797 |
3.11 |
| 2026-06-04 00:00 |
04:54:29.27 |
+02:28:21.2 |
HIP 22797 |
4.02 |
| 2026-06-04 12:00 |
04:54:33.27 |
+02:28:27.8 |
HIP 22797 |
4.97 |
| 2026-06-05 00:00 |
04:54:37.27 |
+02:28:34.1 |
HIP 22797 |
5.93 |
| 2026-06-05 12:00 |
04:54:41.28 |
+02:28:40.4 |
HIP 22797 |
6.91 |
| 2026-06-06 00:00 |
04:54:45.28 |
+02:28:46.4 |
HIP 22797 |
7.89 |
| 2026-06-06 12:00 |
04:54:49.28 |
+02:28:52.3 |
HIP 22797 |
8.88 |
| 2026-06-07 00:00 |
04:54:53.29 |
+02:28:58.0 |
HIP 22797 |
9.87 |
| 2026-06-07 12:00 |
04:54:57.29 |
+02:29:03.5 |
HIP 22797 |
10.86 |
| 2026-06-08 00:00 |
04:55:01.29 |
+02:29:08.9 |
HIP 22797 |
11.85 |
| 2026-06-08 12:00 |
04:55:05.29 |
+02:29:14.1 |
HIP 22797 |
12.84 |
| 2026-06-09 00:00 |
04:55:09.29 |
+02:29:19.1 |
HIP 22797 |
13.84 |
| 2026-06-09 12:00 |
04:55:13.28 |
+02:29:24.0 |
HIP 22797 |
14.83 |
| 2026-06-10 00:00 |
04:55:17.28 |
+02:29:28.7 |
HIP 22797 |
15.83 |
| 2026-06-10 12:00 |
04:55:21.27 |
+02:29:33.2 |
HIP 22797 |
16.82 |
| 2026-06-11 00:00 |
04:55:25.26 |
+02:29:37.6 |
HIP 22797 |
17.81 |
| 2026-06-11 12:00 |
04:55:29.24 |
+02:29:41.8 |
HIP 22797 |
18.80 |
| 2026-06-12 00:00 |
04:55:33.23 |
+02:29:45.8 |
HIP 22797 |
19.80 |
| 2026-06-12 12:00 |
04:55:37.21 |
+02:29:49.6 |
HIP 22797 |
20.79 |
| 2026-06-13 00:00 |
04:55:41.19 |
+02:29:53.3 |
HIP 22797 |
21.78 |
| 2026-06-13 12:00 |
04:55:45.16 |
+02:29:56.8 |
HIP 22797 |
22.77 |
| 2026-06-14 00:00 |
04:55:49.13 |
+02:30:00.1 |
HIP 22797 |
23.75 |
| 2026-06-14 12:00 |
04:55:53.09 |
+02:30:03.3 |
HIP 22797 |
24.74 |
| 2026-06-15 00:00 |
04:55:57.05 |
+02:30:06.2 |
HIP 22797 |
25.73 |
| 2026-06-15 12:00 |
04:56:01.01 |
+02:30:09.0 |
HIP 22940 |
26.05 |
| 2026-06-16 00:00 |
04:56:04.96 |
+02:30:11.7 |
HIP 22940 |
25.94 |
| 2026-06-16 12:00 |
04:56:08.91 |
+02:30:14.1 |
HIP 22940 |
25.86 |
| 2026-06-17 00:00 |
04:56:12.84 |
+02:30:16.4 |
HIP 22940 |
25.83 |
| 2026-06-17 12:00 |
04:56:16.78 |
+02:30:18.5 |
HIP 22940 |
25.83 |
| 2026-06-18 00:00 |
04:56:20.71 |
+02:30:20.4 |
HIP 22940 |
25.88 |
| 2026-06-18 12:00 |
04:56:24.63 |
+02:30:22.2 |
HIP 22940 |
25.96 |
| 2026-06-19 00:00 |
04:56:28.54 |
+02:30:23.8 |
HIP 22940 |
26.08 |
| 2026-06-19 12:00 |
04:56:32.45 |
+02:30:25.2 |
HIP 22940 |
26.25 |
| 2026-06-20 00:00 |
04:56:36.35 |
+02:30:26.4 |
HIP 22940 |
26.45 |
| 2026-06-20 12:00 |
04:56:40.24 |
+02:30:27.5 |
HIP 22940 |
26.68 |
| 2026-06-21 00:00 |
04:56:44.13 |
+02:30:28.4 |
HIP 22940 |
26.95 |
| 2026-06-21 12:00 |
04:56:48.01 |
+02:30:29.1 |
HIP 22940 |
27.26 |
| 2026-06-22 00:00 |
04:56:51.88 |
+02:30:29.6 |
HIP 22940 |
27.60 |