| Parameter |
Value |
| Designation |
C/1978 R3 (Machholz) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1978-08-13T16:08:35.136960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:27Z |
| Obs used |
46 |
| NEO |
- |
| M1 |
8.300 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1978-11-02.0000000 |
| e |
1.00028144 |
| q (au) |
1.771588 |
| a (au) |
-6294.758943 |
| i (deg) |
130.636426 |
| Ω (om, deg) |
290.677833 |
| ω (w, deg) |
224.754011 |
| M (ma, deg) |
0.000159 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.180 + 2.924\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.180 |
| n |
2.924 |
| gf |
1.000 |
| gb |
-1.000 |
| 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) |
| 2026-07-29 00:00 |
18:07:46.90 |
-03:13:01.6 |
HIP 88740 |
12.79 |
| 2026-07-29 12:00 |
18:07:45.52 |
-03:13:06.2 |
HIP 88740 |
12.44 |
| 2026-07-30 00:00 |
18:07:44.16 |
-03:13:10.8 |
HIP 88740 |
12.09 |
| 2026-07-30 12:00 |
18:07:42.80 |
-03:13:15.5 |
HIP 88740 |
11.75 |
| 2026-07-31 00:00 |
18:07:41.45 |
-03:13:20.2 |
HIP 88740 |
11.41 |
| 2026-07-31 12:00 |
18:07:40.11 |
-03:13:25.0 |
HIP 88740 |
11.07 |
| 2026-08-01 00:00 |
18:07:38.78 |
-03:13:29.9 |
HIP 88740 |
10.74 |
| 2026-08-01 12:00 |
18:07:37.45 |
-03:13:34.8 |
HIP 88740 |
10.40 |
| 2026-08-02 00:00 |
18:07:36.14 |
-03:13:39.7 |
HIP 88740 |
10.07 |
| 2026-08-02 12:00 |
18:07:34.83 |
-03:13:44.8 |
HIP 88740 |
9.74 |
| 2026-08-03 00:00 |
18:07:33.53 |
-03:13:49.8 |
HIP 88740 |
9.41 |
| 2026-08-03 12:00 |
18:07:32.24 |
-03:13:54.9 |
HIP 88740 |
9.09 |
| 2026-08-04 00:00 |
18:07:30.96 |
-03:14:00.1 |
HIP 88740 |
8.77 |
| 2026-08-04 12:00 |
18:07:29.69 |
-03:14:05.3 |
HIP 88740 |
8.45 |
| 2026-08-05 00:00 |
18:07:28.43 |
-03:14:10.6 |
HIP 88740 |
8.14 |
| 2026-08-05 12:00 |
18:07:27.17 |
-03:14:16.0 |
HIP 88740 |
7.83 |
| 2026-08-06 00:00 |
18:07:25.93 |
-03:14:21.3 |
HIP 88740 |
7.52 |
| 2026-08-06 12:00 |
18:07:24.69 |
-03:14:26.8 |
HIP 88740 |
7.22 |
| 2026-08-07 00:00 |
18:07:23.47 |
-03:14:32.3 |
HIP 88740 |
6.92 |
| 2026-08-07 12:00 |
18:07:22.25 |
-03:14:37.8 |
HIP 88740 |
6.62 |
| 2026-08-08 00:00 |
18:07:21.04 |
-03:14:43.4 |
HIP 88740 |
6.33 |
| 2026-08-08 12:00 |
18:07:19.85 |
-03:14:49.0 |
HIP 88740 |
6.05 |
| 2026-08-09 00:00 |
18:07:18.66 |
-03:14:54.7 |
HIP 88740 |
5.77 |
| 2026-08-09 12:00 |
18:07:17.48 |
-03:15:00.4 |
HIP 88740 |
5.50 |
| 2026-08-10 00:00 |
18:07:16.32 |
-03:15:06.2 |
HIP 88740 |
5.23 |
| 2026-08-10 12:00 |
18:07:15.16 |
-03:15:12.0 |
HIP 88740 |
4.97 |
| 2026-08-11 00:00 |
18:07:14.01 |
-03:15:17.9 |
HIP 88740 |
4.72 |
| 2026-08-11 12:00 |
18:07:12.87 |
-03:15:23.8 |
HIP 88740 |
4.47 |
| 2026-08-12 00:00 |
18:07:11.75 |
-03:15:29.8 |
HIP 88740 |
4.24 |
| 2026-08-12 12:00 |
18:07:10.63 |
-03:15:35.8 |
HIP 88740 |
4.02 |
| 2026-08-13 00:00 |
18:07:09.53 |
-03:15:41.9 |
HIP 88740 |
3.81 |
| 2026-08-13 12:00 |
18:07:08.43 |
-03:15:48.0 |
HIP 88740 |
3.62 |
| 2026-08-14 00:00 |
18:07:07.35 |
-03:15:54.1 |
HIP 88740 |
3.44 |
| 2026-08-14 12:00 |
18:07:06.27 |
-03:16:00.3 |
HIP 88740 |
3.28 |
| 2026-08-15 00:00 |
18:07:05.21 |
-03:16:06.6 |
HIP 88740 |
3.14 |
| 2026-08-15 12:00 |
18:07:04.16 |
-03:16:12.8 |
HIP 88740 |
3.02 |
| 2026-08-16 00:00 |
18:07:03.12 |
-03:16:19.2 |
HIP 88740 |
2.93 |
| 2026-08-16 12:00 |
18:07:02.09 |
-03:16:25.5 |
HIP 88740 |
2.87 |
| 2026-08-17 00:00 |
18:07:01.07 |
-03:16:31.9 |
HIP 88740 |
2.83 |
| 2026-08-17 12:00 |
18:07:00.06 |
-03:16:38.4 |
HIP 88740 |
2.82 |
| 2026-08-18 00:00 |
18:06:59.07 |
-03:16:44.9 |
HIP 88740 |
2.84 |
| 2026-08-18 12:00 |
18:06:58.08 |
-03:16:51.4 |
HIP 88740 |
2.89 |
| 2026-08-19 00:00 |
18:06:57.11 |
-03:16:57.9 |
HIP 88740 |
2.96 |