C/1990 E1 (Cernis-Kiuchi-Nakamura)
| Parameter |
Value |
| Designation |
C/1990 E1 (Cernis-Kiuchi-Nakamura) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1990-03-17T07:48:46.033920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
89 |
| NEO |
- |
| M1 |
7.100 |
| K1 |
39.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1990-04-01.0000000 |
| e |
1.00000000 |
| q (au) |
1.068341 |
| a (au) |
- |
| i (deg) |
48.142430 |
| Ω (om, deg) |
348.444903 |
| ω (w, deg) |
100.620374 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (6.814 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.814 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| k |
1.000 |
| 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 |
| 1990-03-17 |
1990-04-29 |
+22.2011 |
-0.831 |
| 1990-04-29 |
1990-05-26 |
+18.5767 |
-0.755 |
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 |
15:44:02.28 |
-69:02:46.8 |
HIP 77386 |
20.52 |
| 2026-02-03 12:00 |
15:44:03.76 |
-69:03:10.1 |
HIP 77386 |
20.43 |
| 2026-02-04 00:00 |
15:44:05.21 |
-69:03:33.4 |
HIP 77386 |
20.35 |
| 2026-02-04 12:00 |
15:44:06.60 |
-69:03:56.8 |
HIP 77386 |
20.29 |
| 2026-02-05 00:00 |
15:44:07.95 |
-69:04:20.1 |
HIP 77386 |
20.24 |
| 2026-02-05 12:00 |
15:44:09.26 |
-69:04:43.5 |
HIP 77386 |
20.20 |
| 2026-02-06 00:00 |
15:44:10.52 |
-69:05:06.9 |
HIP 77386 |
20.17 |
| 2026-02-06 12:00 |
15:44:11.74 |
-69:05:30.2 |
HIP 77386 |
20.15 |
| 2026-02-07 00:00 |
15:44:12.91 |
-69:05:53.6 |
HIP 77386 |
20.15 |
| 2026-02-07 12:00 |
15:44:14.03 |
-69:06:17.0 |
HIP 77386 |
20.16 |
| 2026-02-08 00:00 |
15:44:15.11 |
-69:06:40.4 |
HIP 77386 |
20.18 |
| 2026-02-08 12:00 |
15:44:16.14 |
-69:07:03.8 |
HIP 77386 |
20.21 |
| 2026-02-09 00:00 |
15:44:17.13 |
-69:07:27.2 |
HIP 77386 |
20.25 |
| 2026-02-09 12:00 |
15:44:18.07 |
-69:07:50.5 |
HIP 77386 |
20.31 |
| 2026-02-10 00:00 |
15:44:18.96 |
-69:08:13.9 |
HIP 77386 |
20.37 |
| 2026-02-10 12:00 |
15:44:19.81 |
-69:08:37.3 |
HIP 77386 |
20.45 |
| 2026-02-11 00:00 |
15:44:20.61 |
-69:09:00.6 |
HIP 77386 |
20.54 |
| 2026-02-11 12:00 |
15:44:21.36 |
-69:09:24.0 |
HIP 77386 |
20.64 |
| 2026-02-12 00:00 |
15:44:22.07 |
-69:09:47.3 |
HIP 77386 |
20.75 |
| 2026-02-12 12:00 |
15:44:22.73 |
-69:10:10.6 |
HIP 77386 |
20.88 |
| 2026-02-13 00:00 |
15:44:23.34 |
-69:10:33.9 |
HIP 77386 |
21.01 |
| 2026-02-13 12:00 |
15:44:23.91 |
-69:10:57.2 |
HIP 77386 |
21.15 |
| 2026-02-14 00:00 |
15:44:24.42 |
-69:11:20.4 |
HIP 77386 |
21.30 |
| 2026-02-14 12:00 |
15:44:24.89 |
-69:11:43.6 |
HIP 77386 |
21.46 |
| 2026-02-15 00:00 |
15:44:25.32 |
-69:12:06.9 |
HIP 77386 |
21.63 |
| 2026-02-15 12:00 |
15:44:25.69 |
-69:12:30.0 |
HIP 77386 |
21.81 |
| 2026-02-16 00:00 |
15:44:26.02 |
-69:12:53.2 |
HIP 77386 |
22.00 |
| 2026-02-16 12:00 |
15:44:26.30 |
-69:13:16.3 |
HIP 77386 |
22.19 |
| 2026-02-17 00:00 |
15:44:26.53 |
-69:13:39.4 |
HIP 77386 |
22.40 |
| 2026-02-17 12:00 |
15:44:26.72 |
-69:14:02.5 |
HIP 77386 |
22.61 |
| 2026-02-18 00:00 |
15:44:26.85 |
-69:14:25.5 |
HIP 77386 |
22.83 |
| 2026-02-18 12:00 |
15:44:26.94 |
-69:14:48.5 |
HIP 77386 |
23.06 |
| 2026-02-19 00:00 |
15:44:26.98 |
-69:15:11.4 |
HIP 77386 |
23.29 |
| 2026-02-19 12:00 |
15:44:26.97 |
-69:15:34.3 |
HIP 77386 |
23.53 |
| 2026-02-20 00:00 |
15:44:26.92 |
-69:15:57.2 |
HIP 77386 |
23.78 |
| 2026-02-20 12:00 |
15:44:26.81 |
-69:16:20.0 |
HIP 77386 |
24.03 |
| 2026-02-21 00:00 |
15:44:26.66 |
-69:16:42.8 |
HIP 77386 |
24.29 |
| 2026-02-21 12:00 |
15:44:26.46 |
-69:17:05.5 |
HIP 77386 |
24.56 |
| 2026-02-22 00:00 |
15:44:26.22 |
-69:17:28.2 |
HIP 77386 |
24.83 |
| 2026-02-22 12:00 |
15:44:25.92 |
-69:17:50.8 |
HIP 77386 |
25.10 |
| 2026-02-23 00:00 |
15:44:25.58 |
-69:18:13.4 |
HIP 77386 |
25.39 |
| 2026-02-23 12:00 |
15:44:25.19 |
-69:18:35.9 |
HIP 77386 |
25.67 |
| 2026-02-24 00:00 |
15:44:24.75 |
-69:18:58.4 |
HIP 77386 |
25.96 |