| 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) |
| 2026-07-29 00:00 |
23:08:38.84 |
-14:23:52.7 |
HIP 114371 |
18.40 |
| 2026-07-29 12:00 |
23:08:37.31 |
-14:24:04.5 |
HIP 114371 |
18.67 |
| 2026-07-30 00:00 |
23:08:35.77 |
-14:24:16.3 |
HIP 114371 |
18.96 |
| 2026-07-30 12:00 |
23:08:34.21 |
-14:24:28.2 |
HIP 114371 |
19.25 |
| 2026-07-31 00:00 |
23:08:32.65 |
-14:24:40.0 |
HIP 114371 |
19.54 |
| 2026-07-31 12:00 |
23:08:31.07 |
-14:24:51.9 |
HIP 114371 |
19.85 |
| 2026-08-01 00:00 |
23:08:29.48 |
-14:25:03.9 |
HIP 114371 |
20.16 |
| 2026-08-01 12:00 |
23:08:27.89 |
-14:25:15.8 |
HIP 114371 |
20.48 |
| 2026-08-02 00:00 |
23:08:26.28 |
-14:25:27.8 |
HIP 114371 |
20.80 |
| 2026-08-02 12:00 |
23:08:24.67 |
-14:25:39.9 |
HIP 114371 |
21.14 |
| 2026-08-03 00:00 |
23:08:23.04 |
-14:25:51.9 |
HIP 114371 |
21.47 |
| 2026-08-03 12:00 |
23:08:21.40 |
-14:26:04.0 |
HIP 114371 |
21.82 |
| 2026-08-04 00:00 |
23:08:19.76 |
-14:26:16.1 |
HIP 114371 |
22.17 |
| 2026-08-04 12:00 |
23:08:18.10 |
-14:26:28.2 |
HIP 114371 |
22.52 |
| 2026-08-05 00:00 |
23:08:16.44 |
-14:26:40.3 |
HIP 114371 |
22.88 |
| 2026-08-05 12:00 |
23:08:14.76 |
-14:26:52.5 |
HIP 114371 |
23.24 |
| 2026-08-06 00:00 |
23:08:13.08 |
-14:27:04.7 |
HIP 114371 |
23.62 |
| 2026-08-06 12:00 |
23:08:11.39 |
-14:27:16.9 |
HIP 114371 |
23.99 |
| 2026-08-07 00:00 |
23:08:09.69 |
-14:27:29.1 |
HIP 114371 |
24.37 |
| 2026-08-07 12:00 |
23:08:07.98 |
-14:27:41.4 |
HIP 114371 |
24.76 |
| 2026-08-08 00:00 |
23:08:06.26 |
-14:27:53.7 |
HIP 114371 |
25.15 |
| 2026-08-08 12:00 |
23:08:04.53 |
-14:28:06.0 |
HIP 114371 |
25.54 |
| 2026-08-09 00:00 |
23:08:02.79 |
-14:28:18.3 |
HIP 114371 |
25.94 |
| 2026-08-09 12:00 |
23:08:01.05 |
-14:28:30.6 |
HIP 114371 |
26.34 |
| 2026-08-10 00:00 |
23:07:59.30 |
-14:28:42.9 |
HIP 114371 |
26.75 |
| 2026-08-10 12:00 |
23:07:57.54 |
-14:28:55.3 |
HIP 114371 |
27.16 |
| 2026-08-11 00:00 |
23:07:55.77 |
-14:29:07.6 |
HIP 114371 |
27.58 |
| 2026-08-11 12:00 |
23:07:53.99 |
-14:29:20.0 |
HIP 114371 |
28.00 |
| 2026-08-12 00:00 |
23:07:52.21 |
-14:29:32.4 |
HIP 114058 |
28.16 |
| 2026-08-12 12:00 |
23:07:50.41 |
-14:29:44.8 |
HIP 114058 |
27.75 |
| 2026-08-13 00:00 |
23:07:48.61 |
-14:29:57.1 |
HIP 114058 |
27.34 |
| 2026-08-13 12:00 |
23:07:46.81 |
-14:30:09.6 |
HIP 114058 |
26.93 |
| 2026-08-14 00:00 |
23:07:44.99 |
-14:30:22.0 |
HIP 114058 |
26.53 |
| 2026-08-14 12:00 |
23:07:43.17 |
-14:30:34.4 |
HIP 114058 |
26.12 |
| 2026-08-15 00:00 |
23:07:41.34 |
-14:30:46.8 |
HIP 114058 |
25.71 |
| 2026-08-15 12:00 |
23:07:39.50 |
-14:30:59.2 |
HIP 114058 |
25.31 |
| 2026-08-16 00:00 |
23:07:37.66 |
-14:31:11.6 |
HIP 114058 |
24.91 |
| 2026-08-16 12:00 |
23:07:35.81 |
-14:31:24.1 |
HIP 114058 |
24.51 |
| 2026-08-17 00:00 |
23:07:33.96 |
-14:31:36.5 |
HIP 114058 |
24.11 |
| 2026-08-17 12:00 |
23:07:32.10 |
-14:31:48.9 |
HIP 114058 |
23.71 |
| 2026-08-18 00:00 |
23:07:30.23 |
-14:32:01.3 |
HIP 114058 |
23.31 |
| 2026-08-18 12:00 |
23:07:28.36 |
-14:32:13.8 |
HIP 114058 |
22.92 |
| 2026-08-19 00:00 |
23:07:26.48 |
-14:32:26.2 |
HIP 114113 |
22.52 |