| 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) |
| 2026-09-20 00:00 |
05:03:02.59 |
+01:51:41.8 |
HIP 23510 |
10.45 |
| 2026-09-20 12:00 |
05:03:02.03 |
+01:51:20.0 |
HIP 23510 |
10.17 |
| 2026-09-21 00:00 |
05:03:01.44 |
+01:50:58.3 |
HIP 23510 |
9.90 |
| 2026-09-21 12:00 |
05:03:00.82 |
+01:50:36.4 |
HIP 23510 |
9.63 |
| 2026-09-22 00:00 |
05:03:00.16 |
+01:50:14.6 |
HIP 23510 |
9.39 |
| 2026-09-22 12:00 |
05:02:59.47 |
+01:49:52.8 |
HIP 23510 |
9.15 |
| 2026-09-23 00:00 |
05:02:58.75 |
+01:49:30.9 |
HIP 23510 |
8.93 |
| 2026-09-23 12:00 |
05:02:57.99 |
+01:49:09.0 |
HIP 23510 |
8.74 |
| 2026-09-24 00:00 |
05:02:57.21 |
+01:48:47.1 |
HIP 23510 |
8.56 |
| 2026-09-24 12:00 |
05:02:56.39 |
+01:48:25.3 |
HIP 23510 |
8.40 |
| 2026-09-25 00:00 |
05:02:55.53 |
+01:48:03.4 |
HIP 23510 |
8.26 |
| 2026-09-25 12:00 |
05:02:54.65 |
+01:47:41.4 |
HIP 23510 |
8.16 |
| 2026-09-26 00:00 |
05:02:53.73 |
+01:47:19.5 |
HIP 23510 |
8.08 |
| 2026-09-26 12:00 |
05:02:52.78 |
+01:46:57.6 |
HIP 23510 |
8.02 |
| 2026-09-27 00:00 |
05:02:51.79 |
+01:46:35.7 |
HIP 23510 |
8.00 |
| 2026-09-27 12:00 |
05:02:50.78 |
+01:46:13.8 |
HIP 23510 |
8.01 |
| 2026-09-28 00:00 |
05:02:49.73 |
+01:45:51.9 |
HIP 23510 |
8.05 |
| 2026-09-28 12:00 |
05:02:48.64 |
+01:45:29.9 |
HIP 23510 |
8.12 |
| 2026-09-29 00:00 |
05:02:47.53 |
+01:45:08.0 |
HIP 23510 |
8.23 |
| 2026-09-29 12:00 |
05:02:46.38 |
+01:44:46.1 |
HIP 23510 |
8.36 |
| 2026-09-30 00:00 |
05:02:45.21 |
+01:44:24.2 |
HIP 23510 |
8.53 |
| 2026-09-30 12:00 |
05:02:44.00 |
+01:44:02.3 |
HIP 23510 |
8.73 |
| 2026-10-01 00:00 |
05:02:42.75 |
+01:43:40.4 |
HIP 23510 |
8.95 |
| 2026-10-01 12:00 |
05:02:41.48 |
+01:43:18.6 |
HIP 23510 |
9.21 |
| 2026-10-02 00:00 |
05:02:40.17 |
+01:42:56.7 |
HIP 23510 |
9.49 |
| 2026-10-02 12:00 |
05:02:38.83 |
+01:42:34.9 |
HIP 23510 |
9.79 |
| 2026-10-03 00:00 |
05:02:37.46 |
+01:42:13.1 |
HIP 23510 |
10.12 |
| 2026-10-03 12:00 |
05:02:36.06 |
+01:41:51.3 |
HIP 23421 |
10.22 |
| 2026-10-04 00:00 |
05:02:34.62 |
+01:41:29.5 |
HIP 23421 |
9.73 |
| 2026-10-04 12:00 |
05:02:33.16 |
+01:41:07.7 |
HIP 23421 |
9.23 |
| 2026-10-05 00:00 |
05:02:31.66 |
+01:40:46.0 |
HIP 23421 |
8.73 |
| 2026-10-05 12:00 |
05:02:30.13 |
+01:40:24.3 |
HIP 23421 |
8.23 |
| 2026-10-06 00:00 |
05:02:28.57 |
+01:40:02.6 |
HIP 23421 |
7.72 |
| 2026-10-06 12:00 |
05:02:26.98 |
+01:39:40.9 |
HIP 23421 |
7.20 |
| 2026-10-07 00:00 |
05:02:25.35 |
+01:39:19.3 |
HIP 23421 |
6.69 |
| 2026-10-07 12:00 |
05:02:23.70 |
+01:38:57.7 |
HIP 23421 |
6.17 |
| 2026-10-08 00:00 |
05:02:22.01 |
+01:38:36.1 |
HIP 23421 |
5.65 |
| 2026-10-08 12:00 |
05:02:20.30 |
+01:38:14.6 |
HIP 23421 |
5.12 |
| 2026-10-09 00:00 |
05:02:18.55 |
+01:37:53.1 |
HIP 23421 |
4.60 |
| 2026-10-09 12:00 |
05:02:16.77 |
+01:37:31.7 |
HIP 23421 |
4.09 |
| 2026-10-10 00:00 |
05:02:14.96 |
+01:37:10.3 |
HIP 23421 |
3.58 |
| 2026-10-10 12:00 |
05:02:13.12 |
+01:36:48.9 |
HIP 23421 |
3.09 |
| 2026-10-11 00:00 |
05:02:11.25 |
+01:36:27.6 |
HIP 23421 |
2.63 |