| Parameter |
Value |
| Designation |
C/1991 R1 (McNaught-Russell) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1990-11-10T22:00:23.633280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:41Z |
| Obs used |
41 |
| NEO |
- |
| M1 |
4.400 |
| K1 |
11.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1993-05-02.0000000 |
| e |
0.99985167 |
| q (au) |
6.981918 |
| a (au) |
47069.984909 |
| i (deg) |
104.522092 |
| Ω (om, deg) |
150.114710 |
| ω (w, deg) |
149.130210 |
| M (ma, deg) |
0.000087 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.517 + 4.076\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.517 |
| n |
4.076 |
| gf |
0.931 |
| gb |
-0.999 |
| k |
1.000 |
| δ90 |
9.878 |
| 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) |
| 2026-06-01 00:00 |
09:13:33.68 |
-60:05:57.4 |
HIP 45256 |
5.18 |
| 2026-06-01 12:00 |
09:13:35.43 |
-60:05:27.6 |
HIP 45256 |
5.71 |
| 2026-06-02 00:00 |
09:13:37.21 |
-60:04:58.0 |
HIP 45256 |
6.24 |
| 2026-06-02 12:00 |
09:13:39.03 |
-60:04:28.6 |
HIP 45256 |
6.77 |
| 2026-06-03 00:00 |
09:13:40.87 |
-60:03:59.2 |
HIP 45256 |
7.31 |
| 2026-06-03 12:00 |
09:13:42.74 |
-60:03:30.0 |
HIP 45256 |
7.84 |
| 2026-06-04 00:00 |
09:13:44.65 |
-60:03:01.0 |
HIP 45351 |
7.45 |
| 2026-06-04 12:00 |
09:13:46.58 |
-60:02:32.1 |
HIP 45351 |
6.95 |
| 2026-06-05 00:00 |
09:13:48.54 |
-60:02:03.3 |
HIP 45351 |
6.45 |
| 2026-06-05 12:00 |
09:13:50.53 |
-60:01:34.6 |
HIP 45351 |
5.96 |
| 2026-06-06 00:00 |
09:13:52.55 |
-60:01:06.1 |
HIP 45351 |
5.48 |
| 2026-06-06 12:00 |
09:13:54.60 |
-60:00:37.8 |
HIP 45351 |
5.01 |
| 2026-06-07 00:00 |
09:13:56.68 |
-60:00:09.6 |
HIP 45351 |
4.55 |
| 2026-06-07 12:00 |
09:13:58.79 |
-59:59:41.6 |
HIP 45351 |
4.10 |
| 2026-06-08 00:00 |
09:14:00.92 |
-59:59:13.7 |
HIP 45351 |
3.68 |
| 2026-06-08 12:00 |
09:14:03.09 |
-59:58:45.9 |
HIP 45351 |
3.29 |
| 2026-06-09 00:00 |
09:14:05.28 |
-59:58:18.3 |
HIP 45351 |
2.94 |
| 2026-06-09 12:00 |
09:14:07.50 |
-59:57:50.9 |
HIP 45351 |
2.65 |
| 2026-06-10 00:00 |
09:14:09.75 |
-59:57:23.6 |
HIP 45351 |
2.44 |
| 2026-06-10 12:00 |
09:14:12.03 |
-59:56:56.5 |
HIP 45351 |
2.33 |
| 2026-06-11 00:00 |
09:14:14.33 |
-59:56:29.6 |
HIP 45351 |
2.33 |
| 2026-06-11 12:00 |
09:14:16.67 |
-59:56:02.8 |
HIP 45351 |
2.45 |
| 2026-06-12 00:00 |
09:14:19.03 |
-59:55:36.1 |
HIP 45351 |
2.67 |
| 2026-06-12 12:00 |
09:14:21.41 |
-59:55:09.7 |
HIP 45351 |
2.97 |
| 2026-06-13 00:00 |
09:14:23.83 |
-59:54:43.4 |
HIP 45351 |
3.32 |
| 2026-06-13 12:00 |
09:14:26.27 |
-59:54:17.3 |
HIP 45351 |
3.71 |
| 2026-06-14 00:00 |
09:14:28.73 |
-59:53:51.4 |
HIP 45351 |
4.13 |
| 2026-06-14 12:00 |
09:14:31.23 |
-59:53:25.6 |
HIP 45351 |
4.57 |
| 2026-06-15 00:00 |
09:14:33.75 |
-59:53:00.0 |
HIP 45351 |
5.03 |
| 2026-06-15 12:00 |
09:14:36.29 |
-59:52:34.6 |
HIP 45351 |
5.50 |
| 2026-06-16 00:00 |
09:14:38.86 |
-59:52:09.4 |
HIP 45351 |
5.97 |
| 2026-06-16 12:00 |
09:14:41.46 |
-59:51:44.3 |
HIP 45351 |
6.45 |
| 2026-06-17 00:00 |
09:14:44.08 |
-59:51:19.4 |
HIP 45351 |
6.94 |
| 2026-06-17 12:00 |
09:14:46.73 |
-59:50:54.8 |
HIP 45351 |
7.43 |
| 2026-06-18 00:00 |
09:14:49.40 |
-59:50:30.3 |
HIP 45351 |
7.92 |
| 2026-06-18 12:00 |
09:14:52.10 |
-59:50:05.9 |
HIP 45351 |
8.42 |
| 2026-06-19 00:00 |
09:14:54.82 |
-59:49:41.8 |
HIP 45351 |
8.92 |
| 2026-06-19 12:00 |
09:14:57.57 |
-59:49:17.9 |
HIP 45351 |
9.42 |
| 2026-06-20 00:00 |
09:15:00.34 |
-59:48:54.2 |
HIP 45351 |
9.92 |
| 2026-06-20 12:00 |
09:15:03.13 |
-59:48:30.6 |
HIP 45351 |
10.42 |
| 2026-06-21 00:00 |
09:15:05.95 |
-59:48:07.3 |
HIP 45351 |
10.92 |
| 2026-06-21 12:00 |
09:15:08.79 |
-59:47:44.1 |
HIP 45351 |
11.42 |
| 2026-06-22 00:00 |
09:15:11.65 |
-59:47:21.1 |
HIP 45351 |
11.93 |