| 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
$$
M_a = (7.946 + 3.712\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.946 |
| n |
3.712 |
| 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) |
| 2026-05-12 00:00 |
23:10:32.68 |
-51:40:38.4 |
HIP 114301 |
20.85 |
| 2026-05-12 12:00 |
23:10:33.83 |
-51:40:52.9 |
HIP 114301 |
20.81 |
| 2026-05-13 00:00 |
23:10:34.96 |
-51:41:07.5 |
HIP 114301 |
20.77 |
| 2026-05-13 12:00 |
23:10:36.06 |
-51:41:22.3 |
HIP 114301 |
20.73 |
| 2026-05-14 00:00 |
23:10:37.15 |
-51:41:37.2 |
HIP 114301 |
20.69 |
| 2026-05-14 12:00 |
23:10:38.21 |
-51:41:52.2 |
HIP 114590 |
20.65 |
| 2026-05-15 00:00 |
23:10:39.25 |
-51:42:07.3 |
HIP 114590 |
20.49 |
| 2026-05-15 12:00 |
23:10:40.28 |
-51:42:22.6 |
HIP 114590 |
20.35 |
| 2026-05-16 00:00 |
23:10:41.28 |
-51:42:37.9 |
HIP 114590 |
20.21 |
| 2026-05-16 12:00 |
23:10:42.26 |
-51:42:53.4 |
HIP 114590 |
20.08 |
| 2026-05-17 00:00 |
23:10:43.22 |
-51:43:09.1 |
HIP 114590 |
19.95 |
| 2026-05-17 12:00 |
23:10:44.15 |
-51:43:24.8 |
HIP 114590 |
19.84 |
| 2026-05-18 00:00 |
23:10:45.07 |
-51:43:40.7 |
HIP 114590 |
19.73 |
| 2026-05-18 12:00 |
23:10:45.96 |
-51:43:56.7 |
HIP 114590 |
19.63 |
| 2026-05-19 00:00 |
23:10:46.83 |
-51:44:12.8 |
HIP 114590 |
19.53 |
| 2026-05-19 12:00 |
23:10:47.68 |
-51:44:29.0 |
HIP 114590 |
19.45 |
| 2026-05-20 00:00 |
23:10:48.51 |
-51:44:45.4 |
HIP 114590 |
19.37 |
| 2026-05-20 12:00 |
23:10:49.32 |
-51:45:01.8 |
HIP 114590 |
19.30 |
| 2026-05-21 00:00 |
23:10:50.10 |
-51:45:18.4 |
HIP 114590 |
19.23 |
| 2026-05-21 12:00 |
23:10:50.86 |
-51:45:35.1 |
HIP 114590 |
19.18 |
| 2026-05-22 00:00 |
23:10:51.60 |
-51:45:51.9 |
HIP 114590 |
19.14 |
| 2026-05-22 12:00 |
23:10:52.32 |
-51:46:08.8 |
HIP 114590 |
19.10 |
| 2026-05-23 00:00 |
23:10:53.02 |
-51:46:25.8 |
HIP 114590 |
19.07 |
| 2026-05-23 12:00 |
23:10:53.69 |
-51:46:42.9 |
HIP 114590 |
19.05 |
| 2026-05-24 00:00 |
23:10:54.34 |
-51:47:00.1 |
HIP 114590 |
19.04 |
| 2026-05-24 12:00 |
23:10:54.97 |
-51:47:17.4 |
HIP 114590 |
19.04 |
| 2026-05-25 00:00 |
23:10:55.58 |
-51:47:34.9 |
HIP 114590 |
19.04 |
| 2026-05-25 12:00 |
23:10:56.16 |
-51:47:52.4 |
HIP 114590 |
19.06 |
| 2026-05-26 00:00 |
23:10:56.73 |
-51:48:10.0 |
HIP 114590 |
19.08 |
| 2026-05-26 12:00 |
23:10:57.27 |
-51:48:27.7 |
HIP 114590 |
19.11 |
| 2026-05-27 00:00 |
23:10:57.78 |
-51:48:45.6 |
HIP 114590 |
19.16 |
| 2026-05-27 12:00 |
23:10:58.28 |
-51:49:03.5 |
HIP 114590 |
19.21 |
| 2026-05-28 00:00 |
23:10:58.75 |
-51:49:21.5 |
HIP 114590 |
19.26 |
| 2026-05-28 12:00 |
23:10:59.20 |
-51:49:39.6 |
HIP 114590 |
19.33 |
| 2026-05-29 00:00 |
23:10:59.63 |
-51:49:57.8 |
HIP 114590 |
19.41 |
| 2026-05-29 12:00 |
23:11:00.03 |
-51:50:16.1 |
HIP 114590 |
19.49 |
| 2026-05-30 00:00 |
23:11:00.41 |
-51:50:34.4 |
HIP 114590 |
19.58 |
| 2026-05-30 12:00 |
23:11:00.77 |
-51:50:52.9 |
HIP 114590 |
19.68 |
| 2026-05-31 00:00 |
23:11:01.11 |
-51:51:11.4 |
HIP 114301 |
19.75 |
| 2026-05-31 12:00 |
23:11:01.42 |
-51:51:30.1 |
HIP 114301 |
19.73 |
| 2026-06-01 00:00 |
23:11:01.71 |
-51:51:48.8 |
HIP 114301 |
19.72 |
| 2026-06-01 12:00 |
23:11:01.98 |
-51:52:07.6 |
HIP 114301 |
19.71 |
| 2026-06-02 00:00 |
23:11:02.23 |
-51:52:26.5 |
HIP 114301 |
19.70 |