| Parameter |
Value |
| Designation |
C/1965 S2 (Alcock) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1965-10-26T03:16:48.961920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:17Z |
| Obs used |
29 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1965-10-11.0000000 |
| e |
1.00034477 |
| q (au) |
1.293959 |
| a (au) |
-3753.106898 |
| i (deg) |
65.010799 |
| Ω (om, deg) |
175.619427 |
| ω (w, deg) |
150.520426 |
| M (ma, deg) |
-0.000065 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.066 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.066 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.800 |
| 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) |
| 2026-06-01 00:00 |
09:21:19.34 |
-25:30:27.2 |
HIP 45793 |
16.41 |
| 2026-06-01 12:00 |
09:21:19.91 |
-25:30:16.3 |
HIP 45793 |
16.61 |
| 2026-06-02 00:00 |
09:21:20.49 |
-25:30:05.5 |
HIP 45793 |
16.80 |
| 2026-06-02 12:00 |
09:21:21.08 |
-25:29:54.7 |
HIP 45793 |
17.00 |
| 2026-06-03 00:00 |
09:21:21.68 |
-25:29:44.1 |
HIP 45793 |
17.21 |
| 2026-06-03 12:00 |
09:21:22.29 |
-25:29:33.5 |
HIP 45793 |
17.41 |
| 2026-06-04 00:00 |
09:21:22.91 |
-25:29:23.0 |
HIP 45793 |
17.62 |
| 2026-06-04 12:00 |
09:21:23.55 |
-25:29:12.6 |
HIP 45793 |
17.82 |
| 2026-06-05 00:00 |
09:21:24.19 |
-25:29:02.3 |
HIP 45793 |
18.03 |
| 2026-06-05 12:00 |
09:21:24.85 |
-25:28:52.1 |
HIP 45793 |
18.25 |
| 2026-06-06 00:00 |
09:21:25.51 |
-25:28:42.0 |
HIP 45793 |
18.46 |
| 2026-06-06 12:00 |
09:21:26.19 |
-25:28:31.9 |
HIP 45793 |
18.67 |
| 2026-06-07 00:00 |
09:21:26.88 |
-25:28:22.0 |
HIP 45793 |
18.89 |
| 2026-06-07 12:00 |
09:21:27.57 |
-25:28:12.1 |
HIP 45793 |
19.11 |
| 2026-06-08 00:00 |
09:21:28.28 |
-25:28:02.3 |
HIP 45793 |
19.33 |
| 2026-06-08 12:00 |
09:21:29.00 |
-25:27:52.7 |
HIP 45793 |
19.55 |
| 2026-06-09 00:00 |
09:21:29.73 |
-25:27:43.1 |
HIP 45793 |
19.77 |
| 2026-06-09 12:00 |
09:21:30.47 |
-25:27:33.6 |
HIP 45793 |
20.00 |
| 2026-06-10 00:00 |
09:21:31.22 |
-25:27:24.2 |
HIP 45793 |
20.22 |
| 2026-06-10 12:00 |
09:21:31.98 |
-25:27:14.9 |
HIP 45793 |
20.45 |
| 2026-06-11 00:00 |
09:21:32.75 |
-25:27:05.6 |
HIP 45793 |
20.68 |
| 2026-06-11 12:00 |
09:21:33.53 |
-25:26:56.5 |
HIP 45793 |
20.91 |
| 2026-06-12 00:00 |
09:21:34.33 |
-25:26:47.5 |
HIP 45793 |
21.14 |
| 2026-06-12 12:00 |
09:21:35.13 |
-25:26:38.6 |
HIP 45793 |
21.37 |
| 2026-06-13 00:00 |
09:21:35.94 |
-25:26:29.7 |
HIP 45793 |
21.60 |
| 2026-06-13 12:00 |
09:21:36.76 |
-25:26:21.0 |
HIP 45793 |
21.84 |
| 2026-06-14 00:00 |
09:21:37.59 |
-25:26:12.4 |
HIP 45793 |
22.07 |
| 2026-06-14 12:00 |
09:21:38.43 |
-25:26:03.8 |
HIP 45793 |
22.31 |
| 2026-06-15 00:00 |
09:21:39.29 |
-25:25:55.4 |
HIP 45793 |
22.55 |
| 2026-06-15 12:00 |
09:21:40.15 |
-25:25:47.1 |
HIP 45793 |
22.78 |
| 2026-06-16 00:00 |
09:21:41.02 |
-25:25:38.8 |
HIP 45793 |
23.02 |
| 2026-06-16 12:00 |
09:21:41.90 |
-25:25:30.7 |
HIP 45793 |
23.26 |
| 2026-06-17 00:00 |
09:21:42.79 |
-25:25:22.7 |
HIP 45793 |
23.51 |
| 2026-06-17 12:00 |
09:21:43.69 |
-25:25:14.7 |
HIP 45793 |
23.75 |
| 2026-06-18 00:00 |
09:21:44.60 |
-25:25:06.9 |
HIP 45793 |
23.99 |
| 2026-06-18 12:00 |
09:21:45.52 |
-25:24:59.2 |
HIP 45793 |
24.23 |
| 2026-06-19 00:00 |
09:21:46.44 |
-25:24:51.6 |
HIP 45793 |
24.48 |
| 2026-06-19 12:00 |
09:21:47.38 |
-25:24:44.1 |
HIP 45793 |
24.73 |
| 2026-06-20 00:00 |
09:21:48.33 |
-25:24:36.6 |
HIP 45793 |
24.97 |
| 2026-06-20 12:00 |
09:21:49.28 |
-25:24:29.3 |
HIP 45793 |
25.22 |
| 2026-06-21 00:00 |
09:21:50.25 |
-25:24:22.1 |
HIP 45793 |
25.47 |
| 2026-06-21 12:00 |
09:21:51.22 |
-25:24:15.1 |
HIP 45793 |
25.72 |
| 2026-06-22 00:00 |
09:21:52.20 |
-25:24:08.1 |
HIP 45793 |
25.97 |