| Parameter |
Value |
| Designation |
C/1990 N1 (Tsuchiya-Kiuchi) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1990-09-28T17:50:51.195840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
103 |
| NEO |
- |
| M1 |
5.700 |
| K1 |
10.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1990-09-26.0000000 |
| e |
0.99539790 |
| q (au) |
1.092441 |
| a (au) |
237.378969 |
| i (deg) |
143.783475 |
| Ω (om, deg) |
330.737409 |
| ω (w, deg) |
180.920585 |
| M (ma, deg) |
359.999261 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.880 + 4.904\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.880 |
| n |
4.904 |
| gf |
0.998 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
2.918 |
| 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 |
| 1990-07-13 |
1990-08-19 |
-3.4293 |
+0.264 |
| 1990-10-02 |
1991-01-10 |
+3.4774 |
-0.245 |
| 1991-01-10 |
1991-02-10 |
-5.5276 |
+2.934 |
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 |
23:05:20.47 |
-14:44:50.6 |
HIP 114030 |
19.20 |
| 2026-09-20 12:00 |
23:05:18.51 |
-14:45:00.8 |
HIP 114030 |
19.12 |
| 2026-09-21 00:00 |
23:05:16.56 |
-14:45:10.9 |
HIP 114030 |
19.04 |
| 2026-09-21 12:00 |
23:05:14.61 |
-14:45:21.0 |
HIP 114030 |
18.98 |
| 2026-09-22 00:00 |
23:05:12.67 |
-14:45:31.0 |
HIP 114030 |
18.94 |
| 2026-09-22 12:00 |
23:05:10.73 |
-14:45:40.9 |
HIP 114030 |
18.90 |
| 2026-09-23 00:00 |
23:05:08.80 |
-14:45:50.8 |
HIP 114030 |
18.89 |
| 2026-09-23 12:00 |
23:05:06.87 |
-14:46:00.6 |
HIP 114030 |
18.88 |
| 2026-09-24 00:00 |
23:05:04.94 |
-14:46:10.3 |
HIP 114030 |
18.89 |
| 2026-09-24 12:00 |
23:05:03.02 |
-14:46:20.0 |
HIP 114030 |
18.91 |
| 2026-09-25 00:00 |
23:05:01.11 |
-14:46:29.6 |
HIP 114030 |
18.95 |
| 2026-09-25 12:00 |
23:04:59.20 |
-14:46:39.1 |
HIP 114030 |
19.00 |
| 2026-09-26 00:00 |
23:04:57.29 |
-14:46:48.6 |
HIP 114030 |
19.06 |
| 2026-09-26 12:00 |
23:04:55.39 |
-14:46:57.9 |
HIP 114030 |
19.13 |
| 2026-09-27 00:00 |
23:04:53.50 |
-14:47:07.3 |
HIP 114030 |
19.22 |
| 2026-09-27 12:00 |
23:04:51.61 |
-14:47:16.5 |
HIP 114030 |
19.31 |
| 2026-09-28 00:00 |
23:04:49.73 |
-14:47:25.7 |
HIP 114030 |
19.42 |
| 2026-09-28 12:00 |
23:04:47.85 |
-14:47:34.8 |
HIP 114030 |
19.55 |
| 2026-09-29 00:00 |
23:04:45.98 |
-14:47:43.8 |
HIP 114030 |
19.68 |
| 2026-09-29 12:00 |
23:04:44.11 |
-14:47:52.7 |
HIP 114030 |
19.82 |
| 2026-09-30 00:00 |
23:04:42.25 |
-14:48:01.6 |
HIP 114030 |
19.98 |
| 2026-09-30 12:00 |
23:04:40.40 |
-14:48:10.4 |
HIP 114030 |
20.14 |
| 2026-10-01 00:00 |
23:04:38.55 |
-14:48:19.1 |
HIP 114030 |
20.31 |
| 2026-10-01 12:00 |
23:04:36.71 |
-14:48:27.7 |
HIP 114030 |
20.49 |
| 2026-10-02 00:00 |
23:04:34.88 |
-14:48:36.3 |
HIP 114030 |
20.68 |
| 2026-10-02 12:00 |
23:04:33.05 |
-14:48:44.8 |
HIP 114030 |
20.88 |
| 2026-10-03 00:00 |
23:04:31.23 |
-14:48:53.2 |
HIP 114030 |
21.09 |
| 2026-10-03 12:00 |
23:04:29.42 |
-14:49:01.5 |
HIP 114030 |
21.31 |
| 2026-10-04 00:00 |
23:04:27.62 |
-14:49:09.7 |
HIP 114030 |
21.53 |
| 2026-10-04 12:00 |
23:04:25.82 |
-14:49:17.9 |
HIP 114030 |
21.76 |
| 2026-10-05 00:00 |
23:04:24.03 |
-14:49:25.9 |
HIP 114030 |
21.99 |
| 2026-10-05 12:00 |
23:04:22.25 |
-14:49:33.9 |
HIP 114030 |
22.24 |
| 2026-10-06 00:00 |
23:04:20.48 |
-14:49:41.8 |
HIP 114030 |
22.48 |
| 2026-10-06 12:00 |
23:04:18.71 |
-14:49:49.7 |
HIP 114030 |
22.74 |
| 2026-10-07 00:00 |
23:04:16.95 |
-14:49:57.4 |
HIP 114030 |
22.99 |
| 2026-10-07 12:00 |
23:04:15.20 |
-14:50:05.0 |
HIP 114030 |
23.26 |
| 2026-10-08 00:00 |
23:04:13.46 |
-14:50:12.6 |
HIP 114030 |
23.53 |
| 2026-10-08 12:00 |
23:04:11.73 |
-14:50:20.1 |
HIP 113827 |
23.61 |
| 2026-10-09 00:00 |
23:04:10.01 |
-14:50:27.4 |
HIP 113827 |
23.23 |
| 2026-10-09 12:00 |
23:04:08.29 |
-14:50:34.7 |
HIP 113827 |
22.85 |
| 2026-10-10 00:00 |
23:04:06.59 |
-14:50:41.9 |
HIP 113827 |
22.48 |
| 2026-10-10 12:00 |
23:04:04.89 |
-14:50:49.1 |
HIP 113827 |
22.12 |
| 2026-10-11 00:00 |
23:04:03.20 |
-14:50:56.1 |
HIP 113827 |
21.76 |