| 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) |
| 2026-03-26 00:00 |
04:47:02.06 |
+01:51:03.7 |
HIP 22317 |
30.85 |
| 2026-03-26 12:00 |
04:47:03.74 |
+01:51:25.7 |
HIP 22317 |
30.85 |
| 2026-03-27 00:00 |
04:47:05.46 |
+01:51:47.7 |
HIP 22317 |
30.85 |
| 2026-03-27 12:00 |
04:47:07.20 |
+01:52:09.6 |
HIP 22317 |
30.86 |
| 2026-03-28 00:00 |
04:47:08.98 |
+01:52:31.6 |
HIP 22317 |
30.87 |
| 2026-03-28 12:00 |
04:47:10.78 |
+01:52:53.5 |
HIP 22317 |
30.89 |
| 2026-03-29 00:00 |
04:47:12.62 |
+01:53:15.3 |
HIP 22317 |
30.91 |
| 2026-03-29 12:00 |
04:47:14.48 |
+01:53:37.2 |
HIP 22317 |
30.94 |
| 2026-03-30 00:00 |
04:47:16.38 |
+01:53:59.0 |
HIP 22317 |
30.98 |
| 2026-03-30 12:00 |
04:47:18.30 |
+01:54:20.7 |
HIP 22317 |
31.03 |
| 2026-03-31 00:00 |
04:47:20.25 |
+01:54:42.4 |
HIP 22317 |
31.08 |
| 2026-03-31 12:00 |
04:47:22.23 |
+01:55:04.1 |
HIP 22317 |
31.14 |
| 2026-04-01 00:00 |
04:47:24.24 |
+01:55:25.7 |
HIP 22317 |
31.21 |
| 2026-04-01 12:00 |
04:47:26.28 |
+01:55:47.3 |
HIP 22317 |
31.28 |
| 2026-04-02 00:00 |
04:47:28.35 |
+01:56:08.8 |
HIP 22317 |
31.37 |
| 2026-04-02 12:00 |
04:47:30.44 |
+01:56:30.3 |
HIP 22317 |
31.46 |
| 2026-04-03 00:00 |
04:47:32.57 |
+01:56:51.8 |
HIP 22317 |
31.56 |
| 2026-04-03 12:00 |
04:47:34.72 |
+01:57:13.2 |
HIP 22317 |
31.67 |
| 2026-04-04 00:00 |
04:47:36.90 |
+01:57:34.5 |
HIP 22317 |
31.79 |
| 2026-04-04 12:00 |
04:47:39.11 |
+01:57:55.8 |
HIP 22428 |
31.83 |
| 2026-04-05 00:00 |
04:47:41.34 |
+01:58:17.0 |
HIP 22428 |
31.18 |
| 2026-04-05 12:00 |
04:47:43.60 |
+01:58:38.2 |
HIP 22428 |
30.51 |
| 2026-04-06 00:00 |
04:47:45.89 |
+01:58:59.4 |
HIP 22428 |
29.84 |
| 2026-04-06 12:00 |
04:47:48.21 |
+01:59:20.4 |
HIP 22428 |
29.17 |
| 2026-04-07 00:00 |
04:47:50.55 |
+01:59:41.5 |
HIP 22428 |
28.49 |
| 2026-04-07 12:00 |
04:47:52.92 |
+02:00:02.4 |
HIP 22428 |
27.81 |
| 2026-04-08 00:00 |
04:47:55.32 |
+02:00:23.3 |
HIP 22428 |
27.11 |
| 2026-04-08 12:00 |
04:47:57.74 |
+02:00:44.1 |
HIP 22428 |
26.42 |
| 2026-04-09 00:00 |
04:48:00.19 |
+02:01:04.9 |
HIP 22428 |
25.72 |
| 2026-04-09 12:00 |
04:48:02.66 |
+02:01:25.6 |
HIP 22428 |
25.01 |
| 2026-04-10 00:00 |
04:48:05.16 |
+02:01:46.2 |
HIP 22428 |
24.30 |
| 2026-04-10 12:00 |
04:48:07.69 |
+02:02:06.8 |
HIP 22428 |
23.58 |
| 2026-04-11 00:00 |
04:48:10.24 |
+02:02:27.3 |
HIP 22428 |
22.86 |
| 2026-04-11 12:00 |
04:48:12.82 |
+02:02:47.7 |
HIP 22428 |
22.13 |
| 2026-04-12 00:00 |
04:48:15.42 |
+02:03:08.1 |
HIP 22428 |
21.40 |
| 2026-04-12 12:00 |
04:48:18.05 |
+02:03:28.3 |
HIP 22428 |
20.66 |
| 2026-04-13 00:00 |
04:48:20.70 |
+02:03:48.5 |
HIP 22428 |
19.92 |
| 2026-04-13 12:00 |
04:48:23.38 |
+02:04:08.7 |
HIP 22428 |
19.17 |
| 2026-04-14 00:00 |
04:48:26.08 |
+02:04:28.7 |
HIP 22428 |
18.42 |
| 2026-04-14 12:00 |
04:48:28.80 |
+02:04:48.7 |
HIP 22428 |
17.66 |
| 2026-04-15 00:00 |
04:48:31.55 |
+02:05:08.6 |
HIP 22428 |
16.90 |
| 2026-04-15 12:00 |
04:48:34.33 |
+02:05:28.4 |
HIP 22428 |
16.13 |
| 2026-04-16 00:00 |
04:48:37.12 |
+02:05:48.1 |
HIP 22428 |
15.36 |