| Parameter |
Value |
| Designation |
C/1989 Y2 (McKenzie-Russell) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1989-11-07T16:28:56.971200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
45 |
| NEO |
- |
| M1 |
10.000 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1989-12-30.0000000 |
| e |
0.99999649 |
| q (au) |
1.975796 |
| a (au) |
562869.874478 |
| i (deg) |
160.336275 |
| Ω (om, deg) |
293.896265 |
| ω (w, deg) |
191.736136 |
| M (ma, deg) |
0.000000 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.266 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.266 |
| n |
2.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
20:18:37.39 |
-22:43:28.5 |
HIP 100053 |
12.20 |
| 2026-09-20 12:00 |
20:18:36.15 |
-22:43:30.8 |
HIP 100053 |
12.00 |
| 2026-09-21 00:00 |
20:18:34.92 |
-22:43:33.1 |
HIP 100053 |
11.80 |
| 2026-09-21 12:00 |
20:18:33.70 |
-22:43:35.3 |
HIP 100053 |
11.61 |
| 2026-09-22 00:00 |
20:18:32.50 |
-22:43:37.5 |
HIP 100053 |
11.42 |
| 2026-09-22 12:00 |
20:18:31.31 |
-22:43:39.6 |
HIP 100053 |
11.24 |
| 2026-09-23 00:00 |
20:18:30.14 |
-22:43:41.7 |
HIP 100053 |
11.07 |
| 2026-09-23 12:00 |
20:18:28.99 |
-22:43:43.7 |
HIP 100053 |
10.90 |
| 2026-09-24 00:00 |
20:18:27.85 |
-22:43:45.6 |
HIP 100053 |
10.74 |
| 2026-09-24 12:00 |
20:18:26.72 |
-22:43:47.5 |
HIP 100053 |
10.58 |
| 2026-09-25 00:00 |
20:18:25.61 |
-22:43:49.3 |
HIP 100053 |
10.43 |
| 2026-09-25 12:00 |
20:18:24.52 |
-22:43:51.1 |
HIP 100053 |
10.28 |
| 2026-09-26 00:00 |
20:18:23.44 |
-22:43:52.8 |
HIP 100053 |
10.14 |
| 2026-09-26 12:00 |
20:18:22.38 |
-22:43:54.5 |
HIP 100053 |
10.01 |
| 2026-09-27 00:00 |
20:18:21.33 |
-22:43:56.1 |
HIP 100053 |
9.88 |
| 2026-09-27 12:00 |
20:18:20.30 |
-22:43:57.6 |
HIP 100053 |
9.76 |
| 2026-09-28 00:00 |
20:18:19.29 |
-22:43:59.1 |
HIP 100053 |
9.64 |
| 2026-09-28 12:00 |
20:18:18.29 |
-22:44:00.5 |
HIP 100053 |
9.53 |
| 2026-09-29 00:00 |
20:18:17.30 |
-22:44:01.9 |
HIP 100053 |
9.42 |
| 2026-09-29 12:00 |
20:18:16.34 |
-22:44:03.2 |
HIP 100053 |
9.33 |
| 2026-09-30 00:00 |
20:18:15.39 |
-22:44:04.5 |
HIP 100053 |
9.23 |
| 2026-09-30 12:00 |
20:18:14.45 |
-22:44:05.7 |
HIP 100053 |
9.14 |
| 2026-10-01 00:00 |
20:18:13.54 |
-22:44:06.8 |
HIP 100053 |
9.06 |
| 2026-10-01 12:00 |
20:18:12.64 |
-22:44:07.9 |
HIP 100053 |
8.98 |
| 2026-10-02 00:00 |
20:18:11.75 |
-22:44:08.9 |
HIP 100053 |
8.90 |
| 2026-10-02 12:00 |
20:18:10.88 |
-22:44:09.9 |
HIP 100053 |
8.84 |
| 2026-10-03 00:00 |
20:18:10.03 |
-22:44:10.8 |
HIP 100053 |
8.77 |
| 2026-10-03 12:00 |
20:18:09.20 |
-22:44:11.6 |
HIP 100053 |
8.71 |
| 2026-10-04 00:00 |
20:18:08.38 |
-22:44:12.4 |
HIP 100053 |
8.66 |
| 2026-10-04 12:00 |
20:18:07.58 |
-22:44:13.2 |
HIP 100053 |
8.60 |
| 2026-10-05 00:00 |
20:18:06.80 |
-22:44:13.8 |
HIP 100053 |
8.56 |
| 2026-10-05 12:00 |
20:18:06.03 |
-22:44:14.5 |
HIP 100053 |
8.51 |
| 2026-10-06 00:00 |
20:18:05.28 |
-22:44:15.0 |
HIP 100053 |
8.47 |
| 2026-10-06 12:00 |
20:18:04.55 |
-22:44:15.5 |
HIP 100053 |
8.44 |
| 2026-10-07 00:00 |
20:18:03.83 |
-22:44:16.0 |
HIP 100053 |
8.40 |
| 2026-10-07 12:00 |
20:18:03.13 |
-22:44:16.3 |
HIP 100053 |
8.37 |
| 2026-10-08 00:00 |
20:18:02.45 |
-22:44:16.7 |
HIP 100053 |
8.35 |
| 2026-10-08 12:00 |
20:18:01.79 |
-22:44:16.9 |
HIP 100053 |
8.32 |
| 2026-10-09 00:00 |
20:18:01.14 |
-22:44:17.1 |
HIP 100053 |
8.30 |
| 2026-10-09 12:00 |
20:18:00.51 |
-22:44:17.3 |
HIP 100053 |
8.28 |
| 2026-10-10 00:00 |
20:17:59.90 |
-22:44:17.3 |
HIP 100053 |
8.26 |
| 2026-10-10 12:00 |
20:17:59.31 |
-22:44:17.4 |
HIP 100053 |
8.24 |
| 2026-10-11 00:00 |
20:17:58.73 |
-22:44:17.3 |
HIP 100053 |
8.23 |