| 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) |
| 2026-09-20 00:00 |
18:06:20.93 |
-03:24:53.7 |
HIP 88740 |
13.93 |
| 2026-09-20 12:00 |
18:06:20.80 |
-03:25:01.5 |
HIP 88740 |
14.05 |
| 2026-09-21 00:00 |
18:06:20.68 |
-03:25:09.4 |
HIP 88740 |
14.17 |
| 2026-09-21 12:00 |
18:06:20.58 |
-03:25:17.3 |
HIP 88740 |
14.29 |
| 2026-09-22 00:00 |
18:06:20.50 |
-03:25:25.2 |
HIP 88740 |
14.41 |
| 2026-09-22 12:00 |
18:06:20.42 |
-03:25:33.1 |
HIP 88740 |
14.53 |
| 2026-09-23 00:00 |
18:06:20.37 |
-03:25:41.0 |
HIP 88740 |
14.64 |
| 2026-09-23 12:00 |
18:06:20.32 |
-03:25:48.9 |
HIP 88740 |
14.75 |
| 2026-09-24 00:00 |
18:06:20.29 |
-03:25:56.8 |
HIP 88740 |
14.86 |
| 2026-09-24 12:00 |
18:06:20.27 |
-03:26:04.7 |
HIP 88740 |
14.97 |
| 2026-09-25 00:00 |
18:06:20.27 |
-03:26:12.6 |
HIP 88740 |
15.08 |
| 2026-09-25 12:00 |
18:06:20.28 |
-03:26:20.4 |
HIP 88740 |
15.18 |
| 2026-09-26 00:00 |
18:06:20.30 |
-03:26:28.3 |
HIP 88740 |
15.28 |
| 2026-09-26 12:00 |
18:06:20.34 |
-03:26:36.2 |
HIP 88740 |
15.39 |
| 2026-09-27 00:00 |
18:06:20.39 |
-03:26:44.0 |
HIP 88740 |
15.49 |
| 2026-09-27 12:00 |
18:06:20.46 |
-03:26:51.9 |
HIP 88740 |
15.58 |
| 2026-09-28 00:00 |
18:06:20.54 |
-03:26:59.7 |
HIP 88740 |
15.68 |
| 2026-09-28 12:00 |
18:06:20.64 |
-03:27:07.6 |
HIP 88740 |
15.78 |
| 2026-09-29 00:00 |
18:06:20.74 |
-03:27:15.4 |
HIP 88740 |
15.87 |
| 2026-09-29 12:00 |
18:06:20.86 |
-03:27:23.2 |
HIP 88740 |
15.96 |
| 2026-09-30 00:00 |
18:06:21.00 |
-03:27:31.0 |
HIP 88740 |
16.05 |
| 2026-09-30 12:00 |
18:06:21.15 |
-03:27:38.8 |
HIP 88740 |
16.14 |
| 2026-10-01 00:00 |
18:06:21.31 |
-03:27:46.6 |
HIP 88740 |
16.23 |
| 2026-10-01 12:00 |
18:06:21.49 |
-03:27:54.4 |
HIP 88740 |
16.32 |
| 2026-10-02 00:00 |
18:06:21.68 |
-03:28:02.2 |
HIP 88740 |
16.40 |
| 2026-10-02 12:00 |
18:06:21.88 |
-03:28:09.9 |
HIP 88740 |
16.49 |
| 2026-10-03 00:00 |
18:06:22.10 |
-03:28:17.7 |
HIP 88740 |
16.57 |
| 2026-10-03 12:00 |
18:06:22.34 |
-03:28:25.4 |
HIP 88740 |
16.65 |
| 2026-10-04 00:00 |
18:06:22.58 |
-03:28:33.1 |
HIP 88740 |
16.73 |
| 2026-10-04 12:00 |
18:06:22.84 |
-03:28:40.8 |
HIP 88740 |
16.81 |
| 2026-10-05 00:00 |
18:06:23.12 |
-03:28:48.5 |
HIP 88740 |
16.89 |
| 2026-10-05 12:00 |
18:06:23.40 |
-03:28:56.2 |
HIP 88740 |
16.97 |
| 2026-10-06 00:00 |
18:06:23.70 |
-03:29:03.8 |
HIP 88740 |
17.05 |
| 2026-10-06 12:00 |
18:06:24.02 |
-03:29:11.5 |
HIP 88740 |
17.12 |
| 2026-10-07 00:00 |
18:06:24.35 |
-03:29:19.1 |
HIP 88740 |
17.20 |
| 2026-10-07 12:00 |
18:06:24.69 |
-03:29:26.7 |
HIP 88740 |
17.27 |
| 2026-10-08 00:00 |
18:06:25.05 |
-03:29:34.2 |
HIP 88740 |
17.34 |
| 2026-10-08 12:00 |
18:06:25.42 |
-03:29:41.8 |
HIP 88740 |
17.42 |
| 2026-10-09 00:00 |
18:06:25.80 |
-03:29:49.3 |
HIP 88740 |
17.49 |
| 2026-10-09 12:00 |
18:06:26.20 |
-03:29:56.9 |
HIP 88740 |
17.56 |
| 2026-10-10 00:00 |
18:06:26.61 |
-03:30:04.4 |
HIP 88740 |
17.63 |
| 2026-10-10 12:00 |
18:06:27.03 |
-03:30:11.8 |
HIP 88740 |
17.70 |
| 2026-10-11 00:00 |
18:06:27.47 |
-03:30:19.3 |
HIP 88740 |
17.77 |