| 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) |
| 2026-07-29 00:00 |
20:21:51.03 |
-22:34:56.7 |
HIP 100376 |
13.35 |
| 2026-07-29 12:00 |
20:21:48.89 |
-22:35:03.3 |
HIP 100376 |
13.03 |
| 2026-07-30 00:00 |
20:21:46.74 |
-22:35:09.9 |
HIP 100376 |
12.72 |
| 2026-07-30 12:00 |
20:21:44.60 |
-22:35:16.5 |
HIP 100376 |
12.43 |
| 2026-07-31 00:00 |
20:21:42.46 |
-22:35:23.0 |
HIP 100376 |
12.15 |
| 2026-07-31 12:00 |
20:21:40.31 |
-22:35:29.5 |
HIP 100376 |
11.88 |
| 2026-08-01 00:00 |
20:21:38.17 |
-22:35:36.0 |
HIP 100376 |
11.63 |
| 2026-08-01 12:00 |
20:21:36.04 |
-22:35:42.5 |
HIP 100376 |
11.40 |
| 2026-08-02 00:00 |
20:21:33.90 |
-22:35:49.0 |
HIP 100376 |
11.19 |
| 2026-08-02 12:00 |
20:21:31.77 |
-22:35:55.4 |
HIP 100376 |
10.99 |
| 2026-08-03 00:00 |
20:21:29.63 |
-22:36:01.8 |
HIP 100376 |
10.82 |
| 2026-08-03 12:00 |
20:21:27.50 |
-22:36:08.2 |
HIP 100376 |
10.67 |
| 2026-08-04 00:00 |
20:21:25.38 |
-22:36:14.6 |
HIP 100376 |
10.54 |
| 2026-08-04 12:00 |
20:21:23.25 |
-22:36:21.0 |
HIP 100376 |
10.43 |
| 2026-08-05 00:00 |
20:21:21.13 |
-22:36:27.3 |
HIP 100376 |
10.35 |
| 2026-08-05 12:00 |
20:21:19.01 |
-22:36:33.6 |
HIP 100376 |
10.29 |
| 2026-08-06 00:00 |
20:21:16.90 |
-22:36:39.9 |
HIP 100376 |
10.25 |
| 2026-08-06 12:00 |
20:21:14.78 |
-22:36:46.1 |
HIP 100376 |
10.24 |
| 2026-08-07 00:00 |
20:21:12.67 |
-22:36:52.3 |
HIP 100376 |
10.26 |
| 2026-08-07 12:00 |
20:21:10.57 |
-22:36:58.5 |
HIP 100376 |
10.30 |
| 2026-08-08 00:00 |
20:21:08.47 |
-22:37:04.7 |
HIP 100376 |
10.36 |
| 2026-08-08 12:00 |
20:21:06.37 |
-22:37:10.8 |
HIP 100376 |
10.44 |
| 2026-08-09 00:00 |
20:21:04.27 |
-22:37:16.9 |
HIP 100376 |
10.55 |
| 2026-08-09 12:00 |
20:21:02.18 |
-22:37:23.0 |
HIP 100376 |
10.68 |
| 2026-08-10 00:00 |
20:21:00.10 |
-22:37:29.1 |
HIP 100376 |
10.83 |
| 2026-08-10 12:00 |
20:20:58.01 |
-22:37:35.1 |
HIP 100376 |
11.00 |
| 2026-08-11 00:00 |
20:20:55.94 |
-22:37:41.1 |
HIP 100376 |
11.19 |
| 2026-08-11 12:00 |
20:20:53.87 |
-22:37:47.1 |
HIP 100376 |
11.40 |
| 2026-08-12 00:00 |
20:20:51.80 |
-22:37:53.0 |
HIP 100376 |
11.62 |
| 2026-08-12 12:00 |
20:20:49.74 |
-22:37:58.9 |
HIP 100376 |
11.86 |
| 2026-08-13 00:00 |
20:20:47.68 |
-22:38:04.8 |
HIP 100376 |
12.11 |
| 2026-08-13 12:00 |
20:20:45.63 |
-22:38:10.6 |
HIP 100376 |
12.38 |
| 2026-08-14 00:00 |
20:20:43.58 |
-22:38:16.4 |
HIP 100376 |
12.65 |
| 2026-08-14 12:00 |
20:20:41.54 |
-22:38:22.2 |
HIP 100376 |
12.94 |
| 2026-08-15 00:00 |
20:20:39.51 |
-22:38:27.9 |
HIP 100376 |
13.24 |
| 2026-08-15 12:00 |
20:20:37.48 |
-22:38:33.6 |
HIP 100376 |
13.55 |
| 2026-08-16 00:00 |
20:20:35.46 |
-22:38:39.3 |
HIP 100376 |
13.87 |
| 2026-08-16 12:00 |
20:20:33.44 |
-22:38:44.9 |
HIP 100376 |
14.20 |
| 2026-08-17 00:00 |
20:20:31.43 |
-22:38:50.5 |
HIP 100376 |
14.53 |
| 2026-08-17 12:00 |
20:20:29.43 |
-22:38:56.1 |
HIP 100376 |
14.87 |
| 2026-08-18 00:00 |
20:20:27.44 |
-22:39:01.6 |
HIP 100376 |
15.22 |
| 2026-08-18 12:00 |
20:20:25.45 |
-22:39:07.1 |
HIP 100376 |
15.57 |
| 2026-08-19 00:00 |
20:20:23.47 |
-22:39:12.6 |
HIP 100376 |
15.92 |