C/1973 A1 (Heck-Sause)
| Parameter |
Value |
| Designation |
C/1973 A1 (Heck-Sause) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1972-10-05T11:17:13.539840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:22Z |
| Obs used |
190 |
| NEO |
- |
| M1 |
5.500 |
| K1 |
10.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1973-03-02.0000000 |
| e |
1.00057319 |
| q (au) |
2.511110 |
| a (au) |
-4380.958906 |
| i (deg) |
138.630150 |
| Ω (om, deg) |
175.878043 |
| ω (w, deg) |
346.237180 |
| M (ma, deg) |
0.000501 |
Magnitude
Scatter + Global Linear
$$
M_a = (2.285 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
2.285 |
| n |
6.000 |
| 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 |
00:46:30.89 |
+28:53:12.5 |
HIP 3681 |
12.33 |
| 2026-02-03 12:00 |
00:46:31.71 |
+28:53:08.1 |
HIP 3681 |
12.16 |
| 2026-02-04 00:00 |
00:46:32.53 |
+28:53:03.8 |
HIP 3681 |
12.00 |
| 2026-02-04 12:00 |
00:46:33.37 |
+28:52:59.7 |
HIP 3681 |
11.83 |
| 2026-02-05 00:00 |
00:46:34.23 |
+28:52:55.6 |
HIP 3681 |
11.66 |
| 2026-02-05 12:00 |
00:46:35.09 |
+28:52:51.6 |
HIP 3681 |
11.50 |
| 2026-02-06 00:00 |
00:46:35.96 |
+28:52:47.8 |
HIP 3681 |
11.34 |
| 2026-02-06 12:00 |
00:46:36.85 |
+28:52:44.0 |
HIP 3681 |
11.17 |
| 2026-02-07 00:00 |
00:46:37.75 |
+28:52:40.4 |
HIP 3681 |
11.01 |
| 2026-02-07 12:00 |
00:46:38.66 |
+28:52:36.8 |
HIP 3681 |
10.85 |
| 2026-02-08 00:00 |
00:46:39.58 |
+28:52:33.4 |
HIP 3681 |
10.70 |
| 2026-02-08 12:00 |
00:46:40.51 |
+28:52:30.1 |
HIP 3681 |
10.54 |
| 2026-02-09 00:00 |
00:46:41.45 |
+28:52:26.9 |
HIP 3681 |
10.39 |
| 2026-02-09 12:00 |
00:46:42.41 |
+28:52:23.7 |
HIP 3681 |
10.24 |
| 2026-02-10 00:00 |
00:46:43.37 |
+28:52:20.7 |
HIP 3681 |
10.09 |
| 2026-02-10 12:00 |
00:46:44.35 |
+28:52:17.8 |
HIP 3681 |
9.94 |
| 2026-02-11 00:00 |
00:46:45.34 |
+28:52:15.1 |
HIP 3681 |
9.80 |
| 2026-02-11 12:00 |
00:46:46.33 |
+28:52:12.4 |
HIP 3681 |
9.66 |
| 2026-02-12 00:00 |
00:46:47.34 |
+28:52:09.8 |
HIP 3681 |
9.53 |
| 2026-02-12 12:00 |
00:46:48.36 |
+28:52:07.3 |
HIP 3681 |
9.40 |
| 2026-02-13 00:00 |
00:46:49.39 |
+28:52:05.0 |
HIP 3681 |
9.27 |
| 2026-02-13 12:00 |
00:46:50.43 |
+28:52:02.7 |
HIP 3681 |
9.15 |
| 2026-02-14 00:00 |
00:46:51.48 |
+28:52:00.6 |
HIP 3681 |
9.04 |
| 2026-02-14 12:00 |
00:46:52.54 |
+28:51:58.6 |
HIP 3681 |
8.93 |
| 2026-02-15 00:00 |
00:46:53.61 |
+28:51:56.6 |
HIP 3681 |
8.82 |
| 2026-02-15 12:00 |
00:46:54.70 |
+28:51:54.8 |
HIP 3681 |
8.72 |
| 2026-02-16 00:00 |
00:46:55.79 |
+28:51:53.1 |
HIP 3681 |
8.63 |
| 2026-02-16 12:00 |
00:46:56.89 |
+28:51:51.5 |
HIP 3681 |
8.55 |
| 2026-02-17 00:00 |
00:46:58.00 |
+28:51:50.0 |
HIP 3681 |
8.47 |
| 2026-02-17 12:00 |
00:46:59.12 |
+28:51:48.6 |
HIP 3681 |
8.40 |
| 2026-02-18 00:00 |
00:47:00.25 |
+28:51:47.4 |
HIP 3681 |
8.34 |
| 2026-02-18 12:00 |
00:47:01.39 |
+28:51:46.2 |
HIP 3681 |
8.29 |
| 2026-02-19 00:00 |
00:47:02.54 |
+28:51:45.2 |
HIP 3681 |
8.25 |
| 2026-02-19 12:00 |
00:47:03.70 |
+28:51:44.2 |
HIP 3681 |
8.21 |
| 2026-02-20 00:00 |
00:47:04.87 |
+28:51:43.4 |
HIP 3681 |
8.19 |
| 2026-02-20 12:00 |
00:47:06.05 |
+28:51:42.6 |
HIP 3681 |
8.18 |
| 2026-02-21 00:00 |
00:47:07.23 |
+28:51:42.0 |
HIP 3681 |
8.17 |
| 2026-02-21 12:00 |
00:47:08.43 |
+28:51:41.5 |
HIP 3681 |
8.18 |
| 2026-02-22 00:00 |
00:47:09.63 |
+28:51:41.1 |
HIP 3681 |
8.19 |
| 2026-02-22 12:00 |
00:47:10.85 |
+28:51:40.8 |
HIP 3681 |
8.22 |
| 2026-02-23 00:00 |
00:47:12.07 |
+28:51:40.6 |
HIP 3681 |
8.26 |
| 2026-02-23 12:00 |
00:47:13.30 |
+28:51:40.5 |
HIP 3681 |
8.30 |
| 2026-02-24 00:00 |
00:47:14.54 |
+28:51:40.6 |
HIP 3681 |
8.36 |