C/1978 A1 (West)
| Parameter |
Value |
| Designation |
C/1978 A1 (West) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1977-07-21T10:46:21.555840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:26Z |
| Obs used |
60 |
| NEO |
- |
| M1 |
6.000 |
| K1 |
8.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1978-03-26.0000000 |
| e |
1.00269511 |
| q (au) |
5.606239 |
| a (au) |
-2080.153011 |
| i (deg) |
116.921045 |
| Ω (om, deg) |
211.624226 |
| ω (w, deg) |
343.273891 |
| M (ma, deg) |
0.002572 |
Magnitude
Scatter + Global Linear
$$
M_a = (-0.758 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
-0.758 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.506 |
| 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 |
02:34:04.59 |
+60:55:37.8 |
HIP 12067 |
15.39 |
| 2026-02-03 12:00 |
02:34:04.72 |
+60:55:18.4 |
HIP 12067 |
15.61 |
| 2026-02-04 00:00 |
02:34:04.88 |
+60:54:59.0 |
HIP 12067 |
15.82 |
| 2026-02-04 12:00 |
02:34:05.06 |
+60:54:39.6 |
HIP 12067 |
16.04 |
| 2026-02-05 00:00 |
02:34:05.27 |
+60:54:20.4 |
HIP 12067 |
16.26 |
| 2026-02-05 12:00 |
02:34:05.52 |
+60:54:01.2 |
HIP 12067 |
16.48 |
| 2026-02-06 00:00 |
02:34:05.79 |
+60:53:42.1 |
HIP 12067 |
16.70 |
| 2026-02-06 12:00 |
02:34:06.09 |
+60:53:23.0 |
HIP 12067 |
16.92 |
| 2026-02-07 00:00 |
02:34:06.42 |
+60:53:04.0 |
HIP 12067 |
17.14 |
| 2026-02-07 12:00 |
02:34:06.78 |
+60:52:45.1 |
HIP 12067 |
17.36 |
| 2026-02-08 00:00 |
02:34:07.17 |
+60:52:26.2 |
HIP 12067 |
17.58 |
| 2026-02-08 12:00 |
02:34:07.58 |
+60:52:07.5 |
HIP 12067 |
17.80 |
| 2026-02-09 00:00 |
02:34:08.03 |
+60:51:48.8 |
HIP 12067 |
18.02 |
| 2026-02-09 12:00 |
02:34:08.50 |
+60:51:30.1 |
HIP 12067 |
18.24 |
| 2026-02-10 00:00 |
02:34:09.00 |
+60:51:11.6 |
HIP 12067 |
18.46 |
| 2026-02-10 12:00 |
02:34:09.54 |
+60:50:53.1 |
HIP 12009 |
18.38 |
| 2026-02-11 00:00 |
02:34:10.10 |
+60:50:34.7 |
HIP 12009 |
18.06 |
| 2026-02-11 12:00 |
02:34:10.68 |
+60:50:16.4 |
HIP 12009 |
17.75 |
| 2026-02-12 00:00 |
02:34:11.30 |
+60:49:58.2 |
HIP 12009 |
17.44 |
| 2026-02-12 12:00 |
02:34:11.95 |
+60:49:40.1 |
HIP 12009 |
17.12 |
| 2026-02-13 00:00 |
02:34:12.62 |
+60:49:22.0 |
HIP 12009 |
16.81 |
| 2026-02-13 12:00 |
02:34:13.32 |
+60:49:04.1 |
HIP 12009 |
16.50 |
| 2026-02-14 00:00 |
02:34:14.05 |
+60:48:46.2 |
HIP 12009 |
16.19 |
| 2026-02-14 12:00 |
02:34:14.81 |
+60:48:28.4 |
HIP 12009 |
15.88 |
| 2026-02-15 00:00 |
02:34:15.59 |
+60:48:10.7 |
HIP 12009 |
15.57 |
| 2026-02-15 12:00 |
02:34:16.41 |
+60:47:53.1 |
HIP 12009 |
15.26 |
| 2026-02-16 00:00 |
02:34:17.25 |
+60:47:35.6 |
HIP 12009 |
14.95 |
| 2026-02-16 12:00 |
02:34:18.12 |
+60:47:18.2 |
HIP 12009 |
14.65 |
| 2026-02-17 00:00 |
02:34:19.01 |
+60:47:00.9 |
HIP 12009 |
14.34 |
| 2026-02-17 12:00 |
02:34:19.94 |
+60:46:43.7 |
HIP 12009 |
14.03 |
| 2026-02-18 00:00 |
02:34:20.89 |
+60:46:26.6 |
HIP 12009 |
13.73 |
| 2026-02-18 12:00 |
02:34:21.87 |
+60:46:09.5 |
HIP 12009 |
13.42 |
| 2026-02-19 00:00 |
02:34:22.87 |
+60:45:52.6 |
HIP 12009 |
13.12 |
| 2026-02-19 12:00 |
02:34:23.90 |
+60:45:35.8 |
HIP 12009 |
12.82 |
| 2026-02-20 00:00 |
02:34:24.96 |
+60:45:19.1 |
HIP 12009 |
12.52 |
| 2026-02-20 12:00 |
02:34:26.05 |
+60:45:02.5 |
HIP 12009 |
12.22 |
| 2026-02-21 00:00 |
02:34:27.16 |
+60:44:46.0 |
HIP 12009 |
11.92 |
| 2026-02-21 12:00 |
02:34:28.30 |
+60:44:29.6 |
HIP 12009 |
11.62 |
| 2026-02-22 00:00 |
02:34:29.47 |
+60:44:13.3 |
HIP 12009 |
11.33 |
| 2026-02-22 12:00 |
02:34:30.66 |
+60:43:57.1 |
HIP 12009 |
11.04 |
| 2026-02-23 00:00 |
02:34:31.88 |
+60:43:41.0 |
HIP 12009 |
10.74 |
| 2026-02-23 12:00 |
02:34:33.13 |
+60:43:25.1 |
HIP 12009 |
10.45 |
| 2026-02-24 00:00 |
02:34:34.40 |
+60:43:09.2 |
HIP 12009 |
10.17 |