| 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) |
| 2026-06-01 00:00 |
23:10:03.70 |
-14:08:15.6 |
HIP 114371 |
22.63 |
| 2026-06-01 12:00 |
23:10:03.86 |
-14:08:18.7 |
HIP 114371 |
22.59 |
| 2026-06-02 00:00 |
23:10:04.00 |
-14:08:21.9 |
HIP 114371 |
22.54 |
| 2026-06-02 12:00 |
23:10:04.13 |
-14:08:25.2 |
HIP 114371 |
22.49 |
| 2026-06-03 00:00 |
23:10:04.24 |
-14:08:28.6 |
HIP 114371 |
22.44 |
| 2026-06-03 12:00 |
23:10:04.33 |
-14:08:32.2 |
HIP 114371 |
22.39 |
| 2026-06-04 00:00 |
23:10:04.41 |
-14:08:35.8 |
HIP 114371 |
22.33 |
| 2026-06-04 12:00 |
23:10:04.47 |
-14:08:39.5 |
HIP 114371 |
22.27 |
| 2026-06-05 00:00 |
23:10:04.52 |
-14:08:43.3 |
HIP 114371 |
22.21 |
| 2026-06-05 12:00 |
23:10:04.55 |
-14:08:47.3 |
HIP 114371 |
22.15 |
| 2026-06-06 00:00 |
23:10:04.57 |
-14:08:51.3 |
HIP 114371 |
22.08 |
| 2026-06-06 12:00 |
23:10:04.57 |
-14:08:55.4 |
HIP 114371 |
22.01 |
| 2026-06-07 00:00 |
23:10:04.55 |
-14:08:59.6 |
HIP 114371 |
21.94 |
| 2026-06-07 12:00 |
23:10:04.51 |
-14:09:04.0 |
HIP 114371 |
21.87 |
| 2026-06-08 00:00 |
23:10:04.46 |
-14:09:08.4 |
HIP 114371 |
21.79 |
| 2026-06-08 12:00 |
23:10:04.40 |
-14:09:12.9 |
HIP 114371 |
21.72 |
| 2026-06-09 00:00 |
23:10:04.32 |
-14:09:17.5 |
HIP 114371 |
21.64 |
| 2026-06-09 12:00 |
23:10:04.22 |
-14:09:22.2 |
HIP 114371 |
21.56 |
| 2026-06-10 00:00 |
23:10:04.10 |
-14:09:27.0 |
HIP 114371 |
21.47 |
| 2026-06-10 12:00 |
23:10:03.97 |
-14:09:32.0 |
HIP 114371 |
21.39 |
| 2026-06-11 00:00 |
23:10:03.83 |
-14:09:37.0 |
HIP 114371 |
21.30 |
| 2026-06-11 12:00 |
23:10:03.66 |
-14:09:42.1 |
HIP 114371 |
21.21 |
| 2026-06-12 00:00 |
23:10:03.48 |
-14:09:47.3 |
HIP 114371 |
21.12 |
| 2026-06-12 12:00 |
23:10:03.29 |
-14:09:52.6 |
HIP 114371 |
21.02 |
| 2026-06-13 00:00 |
23:10:03.08 |
-14:09:58.0 |
HIP 114371 |
20.92 |
| 2026-06-13 12:00 |
23:10:02.85 |
-14:10:03.5 |
HIP 114371 |
20.83 |
| 2026-06-14 00:00 |
23:10:02.60 |
-14:10:09.1 |
HIP 114371 |
20.72 |
| 2026-06-14 12:00 |
23:10:02.34 |
-14:10:14.7 |
HIP 114371 |
20.62 |
| 2026-06-15 00:00 |
23:10:02.07 |
-14:10:20.5 |
HIP 114371 |
20.52 |
| 2026-06-15 12:00 |
23:10:01.77 |
-14:10:26.4 |
HIP 114371 |
20.41 |
| 2026-06-16 00:00 |
23:10:01.46 |
-14:10:32.4 |
HIP 114371 |
20.30 |
| 2026-06-16 12:00 |
23:10:01.14 |
-14:10:38.4 |
HIP 114371 |
20.19 |
| 2026-06-17 00:00 |
23:10:00.80 |
-14:10:44.6 |
HIP 114371 |
20.08 |
| 2026-06-17 12:00 |
23:10:00.44 |
-14:10:50.8 |
HIP 114371 |
19.96 |
| 2026-06-18 00:00 |
23:10:00.07 |
-14:10:57.1 |
HIP 114371 |
19.84 |
| 2026-06-18 12:00 |
23:09:59.68 |
-14:11:03.6 |
HIP 114371 |
19.73 |
| 2026-06-19 00:00 |
23:09:59.27 |
-14:11:10.1 |
HIP 114371 |
19.61 |
| 2026-06-19 12:00 |
23:09:58.85 |
-14:11:16.7 |
HIP 114371 |
19.49 |
| 2026-06-20 00:00 |
23:09:58.41 |
-14:11:23.4 |
HIP 114371 |
19.36 |
| 2026-06-20 12:00 |
23:09:57.96 |
-14:11:30.2 |
HIP 114371 |
19.24 |
| 2026-06-21 00:00 |
23:09:57.49 |
-14:11:37.1 |
HIP 114371 |
19.11 |
| 2026-06-21 12:00 |
23:09:57.00 |
-14:11:44.0 |
HIP 114371 |
18.99 |
| 2026-06-22 00:00 |
23:09:56.50 |
-14:11:51.1 |
HIP 114371 |
18.86 |