C/2013 E2 (Iwamoto)
| 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
$$
M_a = (11.449 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.449 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.752 |
| 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 |
+5.0958 |
-1.889 |
| 2013-06-03 |
2014-02-02 |
-0.2618 |
-0.079 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
04:47:06.60 |
+01:16:14.2 |
HIP 22317 |
22.79 |
| 2026-02-03 12:00 |
04:47:04.82 |
+01:16:30.3 |
HIP 22317 |
23.04 |
| 2026-02-04 00:00 |
04:47:03.07 |
+01:16:46.5 |
HIP 22317 |
23.28 |
| 2026-02-04 12:00 |
04:47:01.36 |
+01:17:02.9 |
HIP 22317 |
23.53 |
| 2026-02-05 00:00 |
04:46:59.68 |
+01:17:19.5 |
HIP 22317 |
23.78 |
| 2026-02-05 12:00 |
04:46:58.03 |
+01:17:36.1 |
HIP 22317 |
24.02 |
| 2026-02-06 00:00 |
04:46:56.41 |
+01:17:52.9 |
HIP 22317 |
24.27 |
| 2026-02-06 12:00 |
04:46:54.83 |
+01:18:09.9 |
HIP 22317 |
24.51 |
| 2026-02-07 00:00 |
04:46:53.28 |
+01:18:26.9 |
HIP 22317 |
24.75 |
| 2026-02-07 12:00 |
04:46:51.77 |
+01:18:44.1 |
HIP 22317 |
24.99 |
| 2026-02-08 00:00 |
04:46:50.29 |
+01:19:01.4 |
HIP 22317 |
25.23 |
| 2026-02-08 12:00 |
04:46:48.84 |
+01:19:18.9 |
HIP 22317 |
25.47 |
| 2026-02-09 00:00 |
04:46:47.43 |
+01:19:36.4 |
HIP 22317 |
25.70 |
| 2026-02-09 12:00 |
04:46:46.05 |
+01:19:54.1 |
HIP 22317 |
25.93 |
| 2026-02-10 00:00 |
04:46:44.70 |
+01:20:12.0 |
HIP 22317 |
26.16 |
| 2026-02-10 12:00 |
04:46:43.39 |
+01:20:29.9 |
HIP 22317 |
26.39 |
| 2026-02-11 00:00 |
04:46:42.11 |
+01:20:48.0 |
HIP 22317 |
26.61 |
| 2026-02-11 12:00 |
04:46:40.86 |
+01:21:06.1 |
HIP 22317 |
26.83 |
| 2026-02-12 00:00 |
04:46:39.66 |
+01:21:24.4 |
HIP 22317 |
27.04 |
| 2026-02-12 12:00 |
04:46:38.48 |
+01:21:42.8 |
HIP 22317 |
27.25 |
| 2026-02-13 00:00 |
04:46:37.34 |
+01:22:01.4 |
HIP 22317 |
27.46 |
| 2026-02-13 12:00 |
04:46:36.23 |
+01:22:20.0 |
HIP 22317 |
27.66 |
| 2026-02-14 00:00 |
04:46:35.16 |
+01:22:38.7 |
HIP 22317 |
27.86 |
| 2026-02-14 12:00 |
04:46:34.13 |
+01:22:57.6 |
HIP 22078 |
27.91 |
| 2026-02-15 00:00 |
04:46:33.13 |
+01:23:16.6 |
HIP 22078 |
27.54 |
| 2026-02-15 12:00 |
04:46:32.16 |
+01:23:35.6 |
HIP 22078 |
27.18 |
| 2026-02-16 00:00 |
04:46:31.23 |
+01:23:54.8 |
HIP 22078 |
26.82 |
| 2026-02-16 12:00 |
04:46:30.33 |
+01:24:14.1 |
HIP 22078 |
26.48 |
| 2026-02-17 00:00 |
04:46:29.47 |
+01:24:33.4 |
HIP 22078 |
26.14 |
| 2026-02-17 12:00 |
04:46:28.64 |
+01:24:52.9 |
HIP 22078 |
25.81 |
| 2026-02-18 00:00 |
04:46:27.85 |
+01:25:12.5 |
HIP 22078 |
25.49 |
| 2026-02-18 12:00 |
04:46:27.10 |
+01:25:32.1 |
HIP 22078 |
25.18 |
| 2026-02-19 00:00 |
04:46:26.38 |
+01:25:51.9 |
HIP 22078 |
24.88 |
| 2026-02-19 12:00 |
04:46:25.69 |
+01:26:11.7 |
HIP 22078 |
24.58 |
| 2026-02-20 00:00 |
04:46:25.04 |
+01:26:31.7 |
HIP 22078 |
24.30 |
| 2026-02-20 12:00 |
04:46:24.43 |
+01:26:51.7 |
HIP 22078 |
24.02 |
| 2026-02-21 00:00 |
04:46:23.85 |
+01:27:11.8 |
HIP 22078 |
23.76 |
| 2026-02-21 12:00 |
04:46:23.31 |
+01:27:32.0 |
HIP 22078 |
23.51 |
| 2026-02-22 00:00 |
04:46:22.80 |
+01:27:52.3 |
HIP 22078 |
23.26 |
| 2026-02-22 12:00 |
04:46:22.32 |
+01:28:12.6 |
HIP 22078 |
23.03 |
| 2026-02-23 00:00 |
04:46:21.89 |
+01:28:33.1 |
HIP 22078 |
22.81 |
| 2026-02-23 12:00 |
04:46:21.48 |
+01:28:53.6 |
HIP 22078 |
22.60 |
| 2026-02-24 00:00 |
04:46:21.12 |
+01:29:14.2 |
HIP 22078 |
22.41 |