C/1987 Q1 (Rudenko)
| Parameter |
Value |
| Designation |
C/1987 Q1 (Rudenko) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1987-10-09T12:40:34.371840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
90 |
| NEO |
- |
| M1 |
8.400 |
| K1 |
10.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1987-09-27.0000000 |
| e |
1.00044313 |
| q (au) |
0.602602 |
| a (au) |
-1359.867867 |
| i (deg) |
114.875276 |
| Ω (om, deg) |
298.569684 |
| ω (w, deg) |
143.833532 |
| M (ma, deg) |
-0.000246 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.947 + 3.710\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.947 |
| n |
3.710 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-02-03 00:00 |
23:03:02.94 |
-51:45:44.3 |
HIP 113955 |
14.78 |
| 2026-02-03 12:00 |
23:03:05.29 |
-51:45:27.3 |
HIP 113955 |
14.44 |
| 2026-02-04 00:00 |
23:03:07.64 |
-51:45:10.5 |
HIP 113955 |
14.10 |
| 2026-02-04 12:00 |
23:03:10.01 |
-51:44:53.8 |
HIP 113955 |
13.77 |
| 2026-02-05 00:00 |
23:03:12.38 |
-51:44:37.2 |
HIP 113955 |
13.45 |
| 2026-02-05 12:00 |
23:03:14.77 |
-51:44:20.7 |
HIP 113955 |
13.13 |
| 2026-02-06 00:00 |
23:03:17.17 |
-51:44:04.4 |
HIP 113955 |
12.81 |
| 2026-02-06 12:00 |
23:03:19.58 |
-51:43:48.1 |
HIP 113955 |
12.51 |
| 2026-02-07 00:00 |
23:03:22.00 |
-51:43:32.0 |
HIP 113955 |
12.21 |
| 2026-02-07 12:00 |
23:03:24.43 |
-51:43:16.0 |
HIP 113955 |
11.92 |
| 2026-02-08 00:00 |
23:03:26.87 |
-51:43:00.2 |
HIP 113955 |
11.64 |
| 2026-02-08 12:00 |
23:03:29.32 |
-51:42:44.4 |
HIP 113955 |
11.36 |
| 2026-02-09 00:00 |
23:03:31.78 |
-51:42:28.8 |
HIP 113955 |
11.10 |
| 2026-02-09 12:00 |
23:03:34.26 |
-51:42:13.4 |
HIP 113955 |
10.85 |
| 2026-02-10 00:00 |
23:03:36.74 |
-51:41:58.0 |
HIP 113955 |
10.61 |
| 2026-02-10 12:00 |
23:03:39.22 |
-51:41:42.8 |
HIP 113955 |
10.38 |
| 2026-02-11 00:00 |
23:03:41.72 |
-51:41:27.7 |
HIP 113955 |
10.17 |
| 2026-02-11 12:00 |
23:03:44.23 |
-51:41:12.7 |
HIP 113955 |
9.97 |
| 2026-02-12 00:00 |
23:03:46.74 |
-51:40:57.9 |
HIP 113955 |
9.79 |
| 2026-02-12 12:00 |
23:03:49.27 |
-51:40:43.2 |
HIP 113955 |
9.62 |
| 2026-02-13 00:00 |
23:03:51.80 |
-51:40:28.7 |
HIP 113955 |
9.47 |
| 2026-02-13 12:00 |
23:03:54.34 |
-51:40:14.2 |
HIP 113955 |
9.34 |
| 2026-02-14 00:00 |
23:03:56.89 |
-51:40:00.0 |
HIP 113955 |
9.22 |
| 2026-02-14 12:00 |
23:03:59.45 |
-51:39:45.8 |
HIP 113955 |
9.13 |
| 2026-02-15 00:00 |
23:04:02.01 |
-51:39:31.8 |
HIP 113955 |
9.05 |
| 2026-02-15 12:00 |
23:04:04.58 |
-51:39:17.9 |
HIP 113955 |
9.00 |
| 2026-02-16 00:00 |
23:04:07.16 |
-51:39:04.2 |
HIP 113955 |
8.97 |
| 2026-02-16 12:00 |
23:04:09.75 |
-51:38:50.6 |
HIP 113955 |
8.95 |
| 2026-02-17 00:00 |
23:04:12.34 |
-51:38:37.2 |
HIP 113955 |
8.96 |
| 2026-02-17 12:00 |
23:04:14.94 |
-51:38:23.9 |
HIP 113955 |
8.99 |
| 2026-02-18 00:00 |
23:04:17.54 |
-51:38:10.8 |
HIP 113955 |
9.04 |
| 2026-02-18 12:00 |
23:04:20.15 |
-51:37:57.8 |
HIP 113955 |
9.11 |
| 2026-02-19 00:00 |
23:04:22.77 |
-51:37:44.9 |
HIP 113955 |
9.20 |
| 2026-02-19 12:00 |
23:04:25.39 |
-51:37:32.2 |
HIP 113955 |
9.31 |
| 2026-02-20 00:00 |
23:04:28.02 |
-51:37:19.7 |
HIP 113955 |
9.43 |
| 2026-02-20 12:00 |
23:04:30.65 |
-51:37:07.3 |
HIP 113955 |
9.58 |
| 2026-02-21 00:00 |
23:04:33.29 |
-51:36:55.0 |
HIP 113955 |
9.74 |
| 2026-02-21 12:00 |
23:04:35.94 |
-51:36:42.9 |
HIP 113955 |
9.92 |
| 2026-02-22 00:00 |
23:04:38.58 |
-51:36:31.0 |
HIP 113955 |
10.11 |
| 2026-02-22 12:00 |
23:04:41.24 |
-51:36:19.2 |
HIP 113955 |
10.32 |
| 2026-02-23 00:00 |
23:04:43.89 |
-51:36:07.6 |
HIP 113955 |
10.54 |
| 2026-02-23 12:00 |
23:04:46.56 |
-51:35:56.1 |
HIP 113955 |
10.77 |
| 2026-02-24 00:00 |
23:04:49.22 |
-51:35:44.8 |
HIP 113955 |
11.01 |