| 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) |
| 2026-05-12 00:00 |
00:50:59.46 |
+29:09:07.2 |
HIP 3867 |
21.00 |
| 2026-05-12 12:00 |
00:51:00.71 |
+29:09:18.5 |
HIP 3867 |
21.12 |
| 2026-05-13 00:00 |
00:51:01.94 |
+29:09:29.7 |
HIP 3867 |
21.25 |
| 2026-05-13 12:00 |
00:51:03.17 |
+29:09:41.0 |
HIP 3867 |
21.38 |
| 2026-05-14 00:00 |
00:51:04.39 |
+29:09:52.3 |
HIP 3867 |
21.51 |
| 2026-05-14 12:00 |
00:51:05.60 |
+29:10:03.6 |
HIP 3867 |
21.64 |
| 2026-05-15 00:00 |
00:51:06.81 |
+29:10:14.9 |
HIP 3867 |
21.78 |
| 2026-05-15 12:00 |
00:51:08.00 |
+29:10:26.3 |
HIP 3867 |
21.92 |
| 2026-05-16 00:00 |
00:51:09.19 |
+29:10:37.6 |
HIP 3867 |
22.06 |
| 2026-05-16 12:00 |
00:51:10.37 |
+29:10:49.0 |
HIP 3867 |
22.20 |
| 2026-05-17 00:00 |
00:51:11.53 |
+29:11:00.4 |
HIP 3867 |
22.35 |
| 2026-05-17 12:00 |
00:51:12.69 |
+29:11:11.8 |
HIP 3867 |
22.49 |
| 2026-05-18 00:00 |
00:51:13.85 |
+29:11:23.2 |
HIP 3867 |
22.64 |
| 2026-05-18 12:00 |
00:51:14.99 |
+29:11:34.6 |
HIP 4132 |
22.76 |
| 2026-05-19 00:00 |
00:51:16.12 |
+29:11:46.0 |
HIP 4132 |
22.58 |
| 2026-05-19 12:00 |
00:51:17.24 |
+29:11:57.5 |
HIP 4132 |
22.41 |
| 2026-05-20 00:00 |
00:51:18.36 |
+29:12:08.9 |
HIP 4132 |
22.25 |
| 2026-05-20 12:00 |
00:51:19.46 |
+29:12:20.3 |
HIP 4132 |
22.09 |
| 2026-05-21 00:00 |
00:51:20.56 |
+29:12:31.8 |
HIP 4132 |
21.94 |
| 2026-05-21 12:00 |
00:51:21.64 |
+29:12:43.3 |
HIP 4132 |
21.79 |
| 2026-05-22 00:00 |
00:51:22.72 |
+29:12:54.7 |
HIP 4132 |
21.64 |
| 2026-05-22 12:00 |
00:51:23.79 |
+29:13:06.2 |
HIP 4132 |
21.50 |
| 2026-05-23 00:00 |
00:51:24.84 |
+29:13:17.7 |
HIP 4132 |
21.37 |
| 2026-05-23 12:00 |
00:51:25.89 |
+29:13:29.1 |
HIP 4132 |
21.24 |
| 2026-05-24 00:00 |
00:51:26.93 |
+29:13:40.6 |
HIP 4132 |
21.12 |
| 2026-05-24 12:00 |
00:51:27.96 |
+29:13:52.1 |
HIP 4132 |
21.00 |
| 2026-05-25 00:00 |
00:51:28.97 |
+29:14:03.5 |
HIP 4132 |
20.89 |
| 2026-05-25 12:00 |
00:51:29.98 |
+29:14:15.0 |
HIP 4132 |
20.78 |
| 2026-05-26 00:00 |
00:51:30.98 |
+29:14:26.5 |
HIP 4132 |
20.68 |
| 2026-05-26 12:00 |
00:51:31.96 |
+29:14:37.9 |
HIP 4132 |
20.58 |
| 2026-05-27 00:00 |
00:51:32.94 |
+29:14:49.4 |
HIP 4132 |
20.49 |
| 2026-05-27 12:00 |
00:51:33.91 |
+29:15:00.9 |
HIP 4132 |
20.41 |
| 2026-05-28 00:00 |
00:51:34.86 |
+29:15:12.3 |
HIP 4132 |
20.33 |
| 2026-05-28 12:00 |
00:51:35.81 |
+29:15:23.8 |
HIP 4132 |
20.25 |
| 2026-05-29 00:00 |
00:51:36.74 |
+29:15:35.2 |
HIP 4132 |
20.19 |
| 2026-05-29 12:00 |
00:51:37.67 |
+29:15:46.6 |
HIP 4132 |
20.12 |
| 2026-05-30 00:00 |
00:51:38.58 |
+29:15:58.0 |
HIP 4132 |
20.07 |
| 2026-05-30 12:00 |
00:51:39.48 |
+29:16:09.5 |
HIP 4132 |
20.02 |
| 2026-05-31 00:00 |
00:51:40.37 |
+29:16:20.9 |
HIP 4132 |
19.97 |
| 2026-05-31 12:00 |
00:51:41.26 |
+29:16:32.2 |
HIP 4132 |
19.93 |
| 2026-06-01 00:00 |
00:51:42.13 |
+29:16:43.6 |
HIP 4132 |
19.89 |
| 2026-06-01 12:00 |
00:51:42.99 |
+29:16:55.0 |
HIP 4132 |
19.86 |
| 2026-06-02 00:00 |
00:51:43.83 |
+29:17:06.3 |
HIP 4132 |
19.84 |