| Parameter |
Value |
| Designation |
C/1989 Y1 (Skorichenko-George) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1990-04-11T22:18:59.575680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
106 |
| NEO |
- |
| M1 |
5.300 |
| K1 |
12.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1990-02-24.0000000 |
| e |
1.00030135 |
| q (au) |
1.569168 |
| a (au) |
-5207.172639 |
| i (deg) |
59.365874 |
| Ω (om, deg) |
280.009427 |
| ω (w, deg) |
137.833282 |
| M (ma, deg) |
-0.000123 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.464 + 4.016\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.464 |
| n |
4.016 |
| gf |
0.990 |
| gb |
-0.501 |
| k |
1.000 |
| δ90 |
9.995 |
| 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 |
| 1988-06-13 |
1989-12-28 |
+1.3201 |
-0.610 |
| 1989-12-28 |
1990-04-11 |
-4.1215 |
+0.921 |
| 1990-04-12 |
1991-03-18 |
+3.8681 |
+0.256 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
14:08:03.53 |
-66:24:39.6 |
HIP 69023 |
14.96 |
| 2026-03-26 12:00 |
14:07:59.58 |
-66:24:46.2 |
HIP 69023 |
15.04 |
| 2026-03-27 00:00 |
14:07:55.61 |
-66:24:52.6 |
HIP 69023 |
15.12 |
| 2026-03-27 12:00 |
14:07:51.62 |
-66:24:58.8 |
HIP 69023 |
15.21 |
| 2026-03-28 00:00 |
14:07:47.61 |
-66:25:04.8 |
HIP 69023 |
15.31 |
| 2026-03-28 12:00 |
14:07:43.58 |
-66:25:10.6 |
HIP 69023 |
15.42 |
| 2026-03-29 00:00 |
14:07:39.54 |
-66:25:16.1 |
HIP 69023 |
15.53 |
| 2026-03-29 12:00 |
14:07:35.47 |
-66:25:21.4 |
HIP 69023 |
15.65 |
| 2026-03-30 00:00 |
14:07:31.39 |
-66:25:26.5 |
HIP 69023 |
15.77 |
| 2026-03-30 12:00 |
14:07:27.28 |
-66:25:31.4 |
HIP 69023 |
15.90 |
| 2026-03-31 00:00 |
14:07:23.16 |
-66:25:36.1 |
HIP 69023 |
16.04 |
| 2026-03-31 12:00 |
14:07:19.03 |
-66:25:40.6 |
HIP 69023 |
16.19 |
| 2026-04-01 00:00 |
14:07:14.87 |
-66:25:44.8 |
HIP 69023 |
16.34 |
| 2026-04-01 12:00 |
14:07:10.70 |
-66:25:48.8 |
HIP 69023 |
16.50 |
| 2026-04-02 00:00 |
14:07:06.51 |
-66:25:52.7 |
HIP 69023 |
16.66 |
| 2026-04-02 12:00 |
14:07:02.31 |
-66:25:56.2 |
HIP 69023 |
16.83 |
| 2026-04-03 00:00 |
14:06:58.09 |
-66:25:59.6 |
HIP 69023 |
17.01 |
| 2026-04-03 12:00 |
14:06:53.86 |
-66:26:02.8 |
HIP 69023 |
17.19 |
| 2026-04-04 00:00 |
14:06:49.61 |
-66:26:05.7 |
HIP 69023 |
17.38 |
| 2026-04-04 12:00 |
14:06:45.35 |
-66:26:08.4 |
HIP 69023 |
17.57 |
| 2026-04-05 00:00 |
14:06:41.07 |
-66:26:10.9 |
HIP 69023 |
17.77 |
| 2026-04-05 12:00 |
14:06:36.78 |
-66:26:13.2 |
HIP 69023 |
17.98 |
| 2026-04-06 00:00 |
14:06:32.47 |
-66:26:15.3 |
HIP 69023 |
18.19 |
| 2026-04-06 12:00 |
14:06:28.15 |
-66:26:17.1 |
HIP 69023 |
18.40 |
| 2026-04-07 00:00 |
14:06:23.82 |
-66:26:18.7 |
HIP 69023 |
18.62 |
| 2026-04-07 12:00 |
14:06:19.48 |
-66:26:20.1 |
HIP 69023 |
18.85 |
| 2026-04-08 00:00 |
14:06:15.12 |
-66:26:21.3 |
HIP 69023 |
19.08 |
| 2026-04-08 12:00 |
14:06:10.76 |
-66:26:22.2 |
HIP 69023 |
19.31 |
| 2026-04-09 00:00 |
14:06:06.38 |
-66:26:23.0 |
HIP 69023 |
19.55 |
| 2026-04-09 12:00 |
14:06:01.99 |
-66:26:23.5 |
HIP 69023 |
19.79 |
| 2026-04-10 00:00 |
14:05:57.59 |
-66:26:23.8 |
HIP 69023 |
20.04 |
| 2026-04-10 12:00 |
14:05:53.18 |
-66:26:23.9 |
HIP 69023 |
20.29 |
| 2026-04-11 00:00 |
14:05:48.76 |
-66:26:23.7 |
HIP 69023 |
20.55 |
| 2026-04-11 12:00 |
14:05:44.33 |
-66:26:23.3 |
HIP 69023 |
20.81 |
| 2026-04-12 00:00 |
14:05:39.89 |
-66:26:22.7 |
HIP 69023 |
21.07 |
| 2026-04-12 12:00 |
14:05:35.44 |
-66:26:21.9 |
HIP 68692 |
21.23 |
| 2026-04-13 00:00 |
14:05:30.99 |
-66:26:20.9 |
HIP 68692 |
21.00 |
| 2026-04-13 12:00 |
14:05:26.52 |
-66:26:19.6 |
HIP 68692 |
20.79 |
| 2026-04-14 00:00 |
14:05:22.05 |
-66:26:18.1 |
HIP 68692 |
20.58 |
| 2026-04-14 12:00 |
14:05:17.57 |
-66:26:16.4 |
HIP 68692 |
20.39 |
| 2026-04-15 00:00 |
14:05:13.09 |
-66:26:14.5 |
HIP 68692 |
20.21 |
| 2026-04-15 12:00 |
14:05:08.59 |
-66:26:12.3 |
HIP 68692 |
20.03 |
| 2026-04-16 00:00 |
14:05:04.10 |
-66:26:10.0 |
HIP 68692 |
19.87 |