| 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 |
1.000 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
10.000 |
| 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 |
+1.3205 |
-0.610 |
| 1989-12-28 |
1990-04-11 |
-4.1211 |
+0.921 |
| 1990-04-12 |
1991-03-18 |
+3.8685 |
+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) |
| 2026-07-29 00:00 |
13:55:33.13 |
-65:23:02.5 |
HIP 67833 |
15.56 |
| 2026-07-29 12:00 |
13:55:33.68 |
-65:22:39.5 |
HIP 67833 |
15.35 |
| 2026-07-30 00:00 |
13:55:34.26 |
-65:22:16.5 |
HIP 67833 |
15.16 |
| 2026-07-30 12:00 |
13:55:34.88 |
-65:21:53.7 |
HIP 67833 |
14.97 |
| 2026-07-31 00:00 |
13:55:35.54 |
-65:21:30.9 |
HIP 67833 |
14.80 |
| 2026-07-31 12:00 |
13:55:36.23 |
-65:21:08.2 |
HIP 67833 |
14.64 |
| 2026-08-01 00:00 |
13:55:36.96 |
-65:20:45.6 |
HIP 67833 |
14.49 |
| 2026-08-01 12:00 |
13:55:37.72 |
-65:20:23.1 |
HIP 67833 |
14.35 |
| 2026-08-02 00:00 |
13:55:38.52 |
-65:20:00.6 |
HIP 67833 |
14.23 |
| 2026-08-02 12:00 |
13:55:39.36 |
-65:19:38.2 |
HIP 67833 |
14.12 |
| 2026-08-03 00:00 |
13:55:40.23 |
-65:19:16.0 |
HIP 67833 |
14.02 |
| 2026-08-03 12:00 |
13:55:41.14 |
-65:18:53.8 |
HIP 67833 |
13.94 |
| 2026-08-04 00:00 |
13:55:42.09 |
-65:18:31.6 |
HIP 67833 |
13.87 |
| 2026-08-04 12:00 |
13:55:43.07 |
-65:18:09.6 |
HIP 67833 |
13.82 |
| 2026-08-05 00:00 |
13:55:44.08 |
-65:17:47.7 |
HIP 67833 |
13.78 |
| 2026-08-05 12:00 |
13:55:45.13 |
-65:17:25.9 |
HIP 67833 |
13.76 |
| 2026-08-06 00:00 |
13:55:46.22 |
-65:17:04.1 |
HIP 67833 |
13.75 |
| 2026-08-06 12:00 |
13:55:47.34 |
-65:16:42.5 |
HIP 67833 |
13.75 |
| 2026-08-07 00:00 |
13:55:48.50 |
-65:16:20.9 |
HIP 67833 |
13.77 |
| 2026-08-07 12:00 |
13:55:49.70 |
-65:15:59.5 |
HIP 67833 |
13.80 |
| 2026-08-08 00:00 |
13:55:50.93 |
-65:15:38.1 |
HIP 67833 |
13.85 |
| 2026-08-08 12:00 |
13:55:52.19 |
-65:15:16.9 |
HIP 67833 |
13.91 |
| 2026-08-09 00:00 |
13:55:53.49 |
-65:14:55.7 |
HIP 67912 |
13.78 |
| 2026-08-09 12:00 |
13:55:54.83 |
-65:14:34.7 |
HIP 67912 |
13.59 |
| 2026-08-10 00:00 |
13:55:56.20 |
-65:14:13.7 |
HIP 67912 |
13.41 |
| 2026-08-10 12:00 |
13:55:57.60 |
-65:13:52.9 |
HIP 67912 |
13.24 |
| 2026-08-11 00:00 |
13:55:59.04 |
-65:13:32.2 |
HIP 67912 |
13.09 |
| 2026-08-11 12:00 |
13:56:00.51 |
-65:13:11.6 |
HIP 67912 |
12.95 |
| 2026-08-12 00:00 |
13:56:02.02 |
-65:12:51.1 |
HIP 67912 |
12.82 |
| 2026-08-12 12:00 |
13:56:03.57 |
-65:12:30.7 |
HIP 67912 |
12.70 |
| 2026-08-13 00:00 |
13:56:05.14 |
-65:12:10.5 |
HIP 67912 |
12.60 |
| 2026-08-13 12:00 |
13:56:06.76 |
-65:11:50.3 |
HIP 67912 |
12.52 |
| 2026-08-14 00:00 |
13:56:08.40 |
-65:11:30.3 |
HIP 67912 |
12.45 |
| 2026-08-14 12:00 |
13:56:10.08 |
-65:11:10.4 |
HIP 67912 |
12.39 |
| 2026-08-15 00:00 |
13:56:11.79 |
-65:10:50.6 |
HIP 67912 |
12.35 |
| 2026-08-15 12:00 |
13:56:13.54 |
-65:10:31.0 |
HIP 67912 |
12.32 |
| 2026-08-16 00:00 |
13:56:15.32 |
-65:10:11.4 |
HIP 67912 |
12.31 |
| 2026-08-16 12:00 |
13:56:17.14 |
-65:09:52.0 |
HIP 67912 |
12.32 |
| 2026-08-17 00:00 |
13:56:18.98 |
-65:09:32.7 |
HIP 67912 |
12.34 |
| 2026-08-17 12:00 |
13:56:20.86 |
-65:09:13.6 |
HIP 67912 |
12.38 |
| 2026-08-18 00:00 |
13:56:22.78 |
-65:08:54.6 |
HIP 67912 |
12.43 |
| 2026-08-18 12:00 |
13:56:24.72 |
-65:08:35.7 |
HIP 67912 |
12.50 |
| 2026-08-19 00:00 |
13:56:26.70 |
-65:08:16.9 |
HIP 67912 |
12.58 |