| 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) |
| 2026-05-12 00:00 |
14:01:11.69 |
-66:19:13.3 |
HIP 68455 |
3.64 |
| 2026-05-12 12:00 |
14:01:07.42 |
-66:19:00.0 |
HIP 68455 |
3.23 |
| 2026-05-13 00:00 |
14:01:03.17 |
-66:18:46.4 |
HIP 68455 |
2.85 |
| 2026-05-13 12:00 |
14:00:58.93 |
-66:18:32.7 |
HIP 68455 |
2.50 |
| 2026-05-14 00:00 |
14:00:54.71 |
-66:18:18.8 |
HIP 68455 |
2.19 |
| 2026-05-14 12:00 |
14:00:50.50 |
-66:18:04.8 |
HIP 68455 |
1.96 |
| 2026-05-15 00:00 |
14:00:46.31 |
-66:17:50.5 |
HIP 68455 |
1.83 |
| 2026-05-15 12:00 |
14:00:42.13 |
-66:17:36.1 |
HIP 68455 |
1.81 |
| 2026-05-16 00:00 |
14:00:37.97 |
-66:17:21.5 |
HIP 68455 |
1.92 |
| 2026-05-16 12:00 |
14:00:33.83 |
-66:17:06.8 |
HIP 68455 |
2.13 |
| 2026-05-17 00:00 |
14:00:29.70 |
-66:16:51.8 |
HIP 68455 |
2.42 |
| 2026-05-17 12:00 |
14:00:25.59 |
-66:16:36.7 |
HIP 68455 |
2.76 |
| 2026-05-18 00:00 |
14:00:21.50 |
-66:16:21.4 |
HIP 68455 |
3.14 |
| 2026-05-18 12:00 |
14:00:17.43 |
-66:16:05.9 |
HIP 68455 |
3.54 |
| 2026-05-19 00:00 |
14:00:13.37 |
-66:15:50.3 |
HIP 68455 |
3.96 |
| 2026-05-19 12:00 |
14:00:09.34 |
-66:15:34.5 |
HIP 68455 |
4.39 |
| 2026-05-20 00:00 |
14:00:05.32 |
-66:15:18.5 |
HIP 68455 |
4.83 |
| 2026-05-20 12:00 |
14:00:01.32 |
-66:15:02.3 |
HIP 68455 |
5.28 |
| 2026-05-21 00:00 |
13:59:57.34 |
-66:14:46.0 |
HIP 68455 |
5.73 |
| 2026-05-21 12:00 |
13:59:53.38 |
-66:14:29.6 |
HIP 68455 |
6.18 |
| 2026-05-22 00:00 |
13:59:49.45 |
-66:14:12.9 |
HIP 68455 |
6.64 |
| 2026-05-22 12:00 |
13:59:45.53 |
-66:13:56.1 |
HIP 68455 |
7.10 |
| 2026-05-23 00:00 |
13:59:41.63 |
-66:13:39.2 |
HIP 68455 |
7.56 |
| 2026-05-23 12:00 |
13:59:37.76 |
-66:13:22.1 |
HIP 68455 |
8.03 |
| 2026-05-24 00:00 |
13:59:33.90 |
-66:13:04.8 |
HIP 68455 |
8.49 |
| 2026-05-24 12:00 |
13:59:30.07 |
-66:12:47.4 |
HIP 68455 |
8.96 |
| 2026-05-25 00:00 |
13:59:26.26 |
-66:12:29.8 |
HIP 68455 |
9.43 |
| 2026-05-25 12:00 |
13:59:22.47 |
-66:12:12.1 |
HIP 68455 |
9.89 |
| 2026-05-26 00:00 |
13:59:18.71 |
-66:11:54.2 |
HIP 68455 |
10.36 |
| 2026-05-26 12:00 |
13:59:14.96 |
-66:11:36.2 |
HIP 68455 |
10.83 |
| 2026-05-27 00:00 |
13:59:11.24 |
-66:11:18.1 |
HIP 68455 |
11.30 |
| 2026-05-27 12:00 |
13:59:07.55 |
-66:10:59.7 |
HIP 68455 |
11.77 |
| 2026-05-28 00:00 |
13:59:03.88 |
-66:10:41.3 |
HIP 68455 |
12.24 |
| 2026-05-28 12:00 |
13:59:00.23 |
-66:10:22.7 |
HIP 68455 |
12.71 |
| 2026-05-29 00:00 |
13:58:56.60 |
-66:10:04.0 |
HIP 68455 |
13.17 |
| 2026-05-29 12:00 |
13:58:53.00 |
-66:09:45.1 |
HIP 68455 |
13.64 |
| 2026-05-30 00:00 |
13:58:49.43 |
-66:09:26.1 |
HIP 68455 |
14.11 |
| 2026-05-30 12:00 |
13:58:45.87 |
-66:09:06.9 |
HIP 68455 |
14.58 |
| 2026-05-31 00:00 |
13:58:42.35 |
-66:08:47.6 |
HIP 68455 |
15.05 |
| 2026-05-31 12:00 |
13:58:38.85 |
-66:08:28.2 |
HIP 68455 |
15.52 |
| 2026-06-01 00:00 |
13:58:35.37 |
-66:08:08.7 |
HIP 68455 |
15.98 |
| 2026-06-01 12:00 |
13:58:31.92 |
-66:07:49.0 |
HIP 68455 |
16.45 |
| 2026-06-02 00:00 |
13:58:28.50 |
-66:07:29.2 |
HIP 68455 |
16.92 |