C/1989 Y1 (Skorichenko-George)
| 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) |
| 2026-02-03 00:00 |
14:12:08.19 |
-65:57:38.5 |
HIP 69397 |
3.17 |
| 2026-02-03 12:00 |
14:12:07.65 |
-65:58:01.2 |
HIP 69397 |
2.89 |
| 2026-02-04 00:00 |
14:12:07.07 |
-65:58:23.9 |
HIP 69397 |
2.63 |
| 2026-02-04 12:00 |
14:12:06.45 |
-65:58:46.4 |
HIP 69397 |
2.41 |
| 2026-02-05 00:00 |
14:12:05.79 |
-65:59:08.9 |
HIP 69397 |
2.23 |
| 2026-02-05 12:00 |
14:12:05.09 |
-65:59:31.3 |
HIP 69397 |
2.12 |
| 2026-02-06 00:00 |
14:12:04.35 |
-65:59:53.6 |
HIP 69397 |
2.07 |
| 2026-02-06 12:00 |
14:12:03.57 |
-66:00:15.8 |
HIP 69397 |
2.10 |
| 2026-02-07 00:00 |
14:12:02.75 |
-66:00:37.9 |
HIP 69397 |
2.20 |
| 2026-02-07 12:00 |
14:12:01.89 |
-66:01:00.0 |
HIP 69397 |
2.36 |
| 2026-02-08 00:00 |
14:12:00.98 |
-66:01:21.8 |
HIP 69397 |
2.56 |
| 2026-02-08 12:00 |
14:12:00.04 |
-66:01:43.7 |
HIP 69397 |
2.81 |
| 2026-02-09 00:00 |
14:11:59.06 |
-66:02:05.4 |
HIP 69397 |
3.08 |
| 2026-02-09 12:00 |
14:11:58.04 |
-66:02:27.0 |
HIP 69397 |
3.38 |
| 2026-02-10 00:00 |
14:11:56.97 |
-66:02:48.5 |
HIP 69397 |
3.69 |
| 2026-02-10 12:00 |
14:11:55.87 |
-66:03:10.0 |
HIP 69397 |
4.02 |
| 2026-02-11 00:00 |
14:11:54.73 |
-66:03:31.3 |
HIP 69397 |
4.35 |
| 2026-02-11 12:00 |
14:11:53.55 |
-66:03:52.5 |
HIP 69397 |
4.69 |
| 2026-02-12 00:00 |
14:11:52.32 |
-66:04:13.6 |
HIP 69397 |
5.04 |
| 2026-02-12 12:00 |
14:11:51.06 |
-66:04:34.5 |
HIP 69397 |
5.39 |
| 2026-02-13 00:00 |
14:11:49.76 |
-66:04:55.4 |
HIP 69397 |
5.75 |
| 2026-02-13 12:00 |
14:11:48.42 |
-66:05:16.2 |
HIP 69397 |
6.10 |
| 2026-02-14 00:00 |
14:11:47.04 |
-66:05:36.8 |
HIP 69397 |
6.47 |
| 2026-02-14 12:00 |
14:11:45.62 |
-66:05:57.3 |
HIP 69397 |
6.83 |
| 2026-02-15 00:00 |
14:11:44.16 |
-66:06:17.7 |
HIP 69397 |
7.19 |
| 2026-02-15 12:00 |
14:11:42.66 |
-66:06:38.0 |
HIP 69397 |
7.56 |
| 2026-02-16 00:00 |
14:11:41.12 |
-66:06:58.2 |
HIP 69397 |
7.92 |
| 2026-02-16 12:00 |
14:11:39.54 |
-66:07:18.2 |
HIP 69397 |
8.29 |
| 2026-02-17 00:00 |
14:11:37.93 |
-66:07:38.1 |
HIP 69397 |
8.65 |
| 2026-02-17 12:00 |
14:11:36.27 |
-66:07:57.9 |
HIP 69397 |
9.02 |
| 2026-02-18 00:00 |
14:11:34.58 |
-66:08:17.5 |
HIP 69397 |
9.39 |
| 2026-02-18 12:00 |
14:11:32.84 |
-66:08:37.0 |
HIP 69397 |
9.76 |
| 2026-02-19 00:00 |
14:11:31.07 |
-66:08:56.4 |
HIP 69397 |
10.13 |
| 2026-02-19 12:00 |
14:11:29.26 |
-66:09:15.6 |
HIP 69397 |
10.50 |
| 2026-02-20 00:00 |
14:11:27.42 |
-66:09:34.7 |
HIP 69397 |
10.87 |
| 2026-02-20 12:00 |
14:11:25.53 |
-66:09:53.7 |
HIP 69397 |
11.23 |
| 2026-02-21 00:00 |
14:11:23.61 |
-66:10:12.5 |
HIP 69397 |
11.60 |
| 2026-02-21 12:00 |
14:11:21.65 |
-66:10:31.2 |
HIP 69397 |
11.97 |
| 2026-02-22 00:00 |
14:11:19.65 |
-66:10:49.7 |
HIP 69397 |
12.34 |
| 2026-02-22 12:00 |
14:11:17.62 |
-66:11:08.1 |
HIP 69397 |
12.71 |
| 2026-02-23 00:00 |
14:11:15.54 |
-66:11:26.4 |
HIP 69323 |
13.04 |
| 2026-02-23 12:00 |
14:11:13.43 |
-66:11:44.5 |
HIP 69323 |
12.74 |
| 2026-02-24 00:00 |
14:11:11.29 |
-66:12:02.4 |
HIP 69323 |
12.45 |