| Parameter |
Value |
| Designation |
C/1959 Q2 (Alcock) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1959-09-15T21:07:08.423040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:14Z |
| Obs used |
14 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1959-09-04.0000000 |
| e |
1.00043121 |
| q (au) |
0.165808 |
| a (au) |
-384.520510 |
| i (deg) |
108.035726 |
| Ω (om, deg) |
225.841022 |
| ω (w, deg) |
300.535111 |
| M (ma, deg) |
-0.001553 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.563 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.563 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
1.000 |
| 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) |
| 2026-09-20 00:00 |
03:36:31.52 |
+81:26:11.1 |
HIP 18209 |
38.55 |
| 2026-09-20 12:00 |
03:36:27.25 |
+81:26:24.0 |
HIP 18209 |
38.66 |
| 2026-09-21 00:00 |
03:36:22.92 |
+81:26:36.9 |
HIP 18209 |
38.77 |
| 2026-09-21 12:00 |
03:36:18.53 |
+81:26:49.6 |
HIP 18209 |
38.89 |
| 2026-09-22 00:00 |
03:36:14.07 |
+81:27:02.2 |
HIP 18209 |
39.01 |
| 2026-09-22 12:00 |
03:36:09.55 |
+81:27:14.8 |
HIP 18209 |
39.14 |
| 2026-09-23 00:00 |
03:36:04.97 |
+81:27:27.2 |
HIP 18209 |
39.27 |
| 2026-09-23 12:00 |
03:36:00.33 |
+81:27:39.6 |
HIP 18209 |
39.40 |
| 2026-09-24 00:00 |
03:35:55.62 |
+81:27:51.8 |
HIP 18209 |
39.54 |
| 2026-09-24 12:00 |
03:35:50.85 |
+81:28:04.0 |
HIP 18209 |
39.68 |
| 2026-09-25 00:00 |
03:35:46.02 |
+81:28:16.0 |
HIP 18209 |
39.83 |
| 2026-09-25 12:00 |
03:35:41.14 |
+81:28:28.0 |
HIP 18209 |
39.98 |
| 2026-09-26 00:00 |
03:35:36.19 |
+81:28:39.8 |
HIP 18209 |
40.13 |
| 2026-09-26 12:00 |
03:35:31.18 |
+81:28:51.6 |
HIP 18209 |
40.28 |
| 2026-09-27 00:00 |
03:35:26.10 |
+81:29:03.3 |
HIP 18209 |
40.44 |
| 2026-09-27 12:00 |
03:35:20.97 |
+81:29:14.8 |
HIP 18209 |
40.61 |
| 2026-09-28 00:00 |
03:35:15.78 |
+81:29:26.3 |
HIP 18209 |
40.77 |
| 2026-09-28 12:00 |
03:35:10.54 |
+81:29:37.6 |
HIP 18209 |
40.94 |
| 2026-09-29 00:00 |
03:35:05.23 |
+81:29:48.8 |
HIP 18209 |
41.12 |
| 2026-09-29 12:00 |
03:34:59.86 |
+81:30:00.0 |
HIP 18209 |
41.29 |
| 2026-09-30 00:00 |
03:34:54.44 |
+81:30:11.0 |
HIP 18209 |
41.47 |
| 2026-09-30 12:00 |
03:34:48.96 |
+81:30:21.9 |
HIP 18209 |
41.65 |
| 2026-10-01 00:00 |
03:34:43.42 |
+81:30:32.7 |
HIP 18209 |
41.84 |
| 2026-10-01 12:00 |
03:34:37.82 |
+81:30:43.4 |
HIP 18209 |
42.03 |
| 2026-10-02 00:00 |
03:34:32.16 |
+81:30:54.0 |
HIP 18209 |
42.22 |
| 2026-10-02 12:00 |
03:34:26.45 |
+81:31:04.5 |
HIP 18209 |
42.41 |
| 2026-10-03 00:00 |
03:34:20.69 |
+81:31:14.8 |
HIP 18209 |
42.61 |
| 2026-10-03 12:00 |
03:34:14.86 |
+81:31:25.1 |
HIP 18209 |
42.81 |
| 2026-10-04 00:00 |
03:34:08.99 |
+81:31:35.2 |
HIP 18209 |
43.02 |
| 2026-10-04 12:00 |
03:34:03.05 |
+81:31:45.2 |
HIP 18209 |
43.22 |
| 2026-10-05 00:00 |
03:33:57.06 |
+81:31:55.1 |
HIP 15792 |
43.22 |
| 2026-10-05 12:00 |
03:33:51.02 |
+81:32:04.8 |
HIP 15792 |
42.96 |
| 2026-10-06 00:00 |
03:33:44.92 |
+81:32:14.5 |
HIP 15792 |
42.71 |
| 2026-10-06 12:00 |
03:33:38.77 |
+81:32:24.0 |
HIP 15792 |
42.47 |
| 2026-10-07 00:00 |
03:33:32.57 |
+81:32:33.4 |
HIP 15792 |
42.22 |
| 2026-10-07 12:00 |
03:33:26.32 |
+81:32:42.7 |
HIP 15792 |
41.97 |
| 2026-10-08 00:00 |
03:33:20.01 |
+81:32:51.8 |
HIP 15792 |
41.72 |
| 2026-10-08 12:00 |
03:33:13.65 |
+81:33:00.8 |
HIP 15792 |
41.48 |
| 2026-10-09 00:00 |
03:33:07.24 |
+81:33:09.7 |
HIP 15792 |
41.24 |
| 2026-10-09 12:00 |
03:33:00.78 |
+81:33:18.5 |
HIP 15792 |
41.00 |
| 2026-10-10 00:00 |
03:32:54.27 |
+81:33:27.2 |
HIP 15792 |
40.76 |
| 2026-10-10 12:00 |
03:32:47.71 |
+81:33:35.7 |
HIP 15792 |
40.52 |
| 2026-10-11 00:00 |
03:32:41.10 |
+81:33:44.1 |
HIP 15792 |
40.28 |