| 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) |
| 2026-05-12 00:00 |
04:51:29.57 |
+02:20:28.5 |
HIP 22483 |
19.46 |
| 2026-05-12 12:00 |
04:51:33.30 |
+02:20:42.2 |
HIP 22483 |
20.42 |
| 2026-05-13 00:00 |
04:51:37.04 |
+02:20:55.7 |
HIP 22483 |
21.38 |
| 2026-05-13 12:00 |
04:51:40.79 |
+02:21:09.1 |
HIP 22483 |
22.34 |
| 2026-05-14 00:00 |
04:51:44.56 |
+02:21:22.3 |
HIP 22483 |
23.31 |
| 2026-05-14 12:00 |
04:51:48.33 |
+02:21:35.4 |
HIP 22483 |
24.27 |
| 2026-05-15 00:00 |
04:51:52.12 |
+02:21:48.4 |
HIP 22730 |
24.25 |
| 2026-05-15 12:00 |
04:51:55.91 |
+02:22:01.2 |
HIP 22730 |
23.29 |
| 2026-05-16 00:00 |
04:51:59.72 |
+02:22:13.9 |
HIP 22730 |
22.33 |
| 2026-05-16 12:00 |
04:52:03.53 |
+02:22:26.4 |
HIP 22730 |
21.36 |
| 2026-05-17 00:00 |
04:52:07.36 |
+02:22:38.8 |
HIP 22730 |
20.40 |
| 2026-05-17 12:00 |
04:52:11.19 |
+02:22:51.0 |
HIP 22730 |
19.44 |
| 2026-05-18 00:00 |
04:52:15.03 |
+02:23:03.1 |
HIP 22730 |
18.48 |
| 2026-05-18 12:00 |
04:52:18.89 |
+02:23:15.0 |
HIP 22730 |
17.52 |
| 2026-05-19 00:00 |
04:52:22.75 |
+02:23:26.8 |
HIP 22730 |
16.56 |
| 2026-05-19 12:00 |
04:52:26.62 |
+02:23:38.4 |
HIP 22730 |
15.61 |
| 2026-05-20 00:00 |
04:52:30.49 |
+02:23:49.9 |
HIP 22730 |
14.66 |
| 2026-05-20 12:00 |
04:52:34.38 |
+02:24:01.2 |
HIP 22730 |
13.71 |
| 2026-05-21 00:00 |
04:52:38.27 |
+02:24:12.4 |
HIP 22730 |
12.77 |
| 2026-05-21 12:00 |
04:52:42.17 |
+02:24:23.4 |
HIP 22730 |
11.83 |
| 2026-05-22 00:00 |
04:52:46.07 |
+02:24:34.2 |
HIP 22730 |
10.91 |
| 2026-05-22 12:00 |
04:52:49.99 |
+02:24:45.0 |
HIP 22730 |
10.00 |
| 2026-05-23 00:00 |
04:52:53.91 |
+02:24:55.5 |
HIP 22730 |
9.11 |
| 2026-05-23 12:00 |
04:52:57.83 |
+02:25:05.9 |
HIP 22730 |
8.24 |
| 2026-05-24 00:00 |
04:53:01.76 |
+02:25:16.2 |
HIP 22730 |
7.40 |
| 2026-05-24 12:00 |
04:53:05.70 |
+02:25:26.2 |
HIP 22730 |
6.61 |
| 2026-05-25 00:00 |
04:53:09.64 |
+02:25:36.2 |
HIP 22730 |
5.89 |
| 2026-05-25 12:00 |
04:53:13.59 |
+02:25:45.9 |
HIP 22730 |
5.26 |
| 2026-05-26 00:00 |
04:53:17.54 |
+02:25:55.6 |
HIP 22730 |
4.75 |
| 2026-05-26 12:00 |
04:53:21.50 |
+02:26:05.0 |
HIP 22730 |
4.42 |
| 2026-05-27 00:00 |
04:53:25.46 |
+02:26:14.3 |
HIP 22730 |
4.31 |
| 2026-05-27 12:00 |
04:53:29.43 |
+02:26:23.5 |
HIP 22730 |
4.43 |
| 2026-05-28 00:00 |
04:53:33.40 |
+02:26:32.4 |
HIP 22730 |
4.77 |
| 2026-05-28 12:00 |
04:53:37.37 |
+02:26:41.3 |
HIP 22730 |
5.28 |
| 2026-05-29 00:00 |
04:53:41.35 |
+02:26:49.9 |
HIP 22730 |
5.91 |
| 2026-05-29 12:00 |
04:53:45.33 |
+02:26:58.4 |
HIP 22730 |
6.65 |
| 2026-05-30 00:00 |
04:53:49.31 |
+02:27:06.8 |
HIP 22797 |
6.48 |
| 2026-05-30 12:00 |
04:53:53.30 |
+02:27:14.9 |
HIP 22797 |
5.50 |
| 2026-05-31 00:00 |
04:53:57.29 |
+02:27:23.0 |
HIP 22797 |
4.55 |
| 2026-05-31 12:00 |
04:54:01.28 |
+02:27:30.8 |
HIP 22797 |
3.61 |
| 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 |