| Parameter |
Value |
| Designation |
96P/Machholz 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-10-27T23:03:31.547520Z |
| Orbit solution date (soln_date, UTC) |
2025-02-20T21:30:21Z |
| Obs used |
669 |
| NEO |
Yes |
| M1 |
13.700 |
| K1 |
8.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-07-27.0000000 |
| e |
0.95916084 |
| q (au) |
0.123950 |
| a (au) |
3.035069 |
| i (deg) |
58.137900 |
| Ω (om, deg) |
94.254723 |
| ω (w, deg) |
14.792845 |
| M (ma, deg) |
342.671895 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.089 + 4.780\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.089 |
| n |
4.780 |
| gf |
0.800 |
| gb |
-0.781 |
| k |
0.948 |
| δ90 |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2022-05-06 |
2023-01-31 |
-13.7766 |
-12.187 |
| 2023-01-31 |
2023-02-15 |
+1.6478 |
+0.513 |
| 2023-02-15 |
2024-07-14 |
-0.2364 |
-0.358 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
18:19:17.88 |
-40:46:30.3 |
HIP 89843 |
8.71 |
| 2026-09-20 12:00 |
18:19:14.88 |
-40:45:16.6 |
HIP 89843 |
9.28 |
| 2026-09-21 00:00 |
18:19:12.14 |
-40:44:02.9 |
HIP 89843 |
9.97 |
| 2026-09-21 12:00 |
18:19:09.66 |
-40:42:49.2 |
HIP 89843 |
10.72 |
| 2026-09-22 00:00 |
18:19:07.44 |
-40:41:35.5 |
HIP 89843 |
11.53 |
| 2026-09-22 12:00 |
18:19:05.48 |
-40:40:21.8 |
HIP 89843 |
12.39 |
| 2026-09-23 00:00 |
18:19:03.78 |
-40:39:08.1 |
HIP 89745 |
12.85 |
| 2026-09-23 12:00 |
18:19:02.33 |
-40:37:54.4 |
HIP 89745 |
11.60 |
| 2026-09-24 00:00 |
18:19:01.14 |
-40:36:40.8 |
HIP 89745 |
10.35 |
| 2026-09-24 12:00 |
18:19:00.20 |
-40:35:27.2 |
HIP 89745 |
9.11 |
| 2026-09-25 00:00 |
18:18:59.52 |
-40:34:13.7 |
HIP 89745 |
7.88 |
| 2026-09-25 12:00 |
18:18:59.08 |
-40:33:00.2 |
HIP 89745 |
6.66 |
| 2026-09-26 00:00 |
18:18:58.90 |
-40:31:46.8 |
HIP 89745 |
5.45 |
| 2026-09-26 12:00 |
18:18:58.97 |
-40:30:33.4 |
HIP 89745 |
4.26 |
| 2026-09-27 00:00 |
18:18:59.29 |
-40:29:20.2 |
HIP 89745 |
3.12 |
| 2026-09-27 12:00 |
18:18:59.85 |
-40:28:07.0 |
HIP 89745 |
2.11 |
| 2026-09-28 00:00 |
18:19:00.66 |
-40:26:53.9 |
HIP 89745 |
1.50 |
| 2026-09-28 12:00 |
18:19:01.72 |
-40:25:40.8 |
HIP 89745 |
1.80 |
| 2026-09-29 00:00 |
18:19:03.02 |
-40:24:27.9 |
HIP 89745 |
2.73 |
| 2026-09-29 12:00 |
18:19:04.56 |
-40:23:15.1 |
HIP 89745 |
3.86 |
| 2026-09-30 00:00 |
18:19:06.35 |
-40:22:02.4 |
HIP 89745 |
5.07 |
| 2026-09-30 12:00 |
18:19:08.38 |
-40:20:49.8 |
HIP 89745 |
6.32 |
| 2026-10-01 00:00 |
18:19:10.65 |
-40:19:37.4 |
HIP 89745 |
7.59 |
| 2026-10-01 12:00 |
18:19:13.16 |
-40:18:25.0 |
HIP 89745 |
8.89 |
| 2026-10-02 00:00 |
18:19:15.90 |
-40:17:12.8 |
HIP 89745 |
10.20 |
| 2026-10-02 12:00 |
18:19:18.89 |
-40:16:00.7 |
HIP 89745 |
11.53 |
| 2026-10-03 00:00 |
18:19:22.11 |
-40:14:48.8 |
HIP 89881 |
12.45 |
| 2026-10-03 12:00 |
18:19:25.57 |
-40:13:37.0 |
HIP 89881 |
12.01 |
| 2026-10-04 00:00 |
18:19:29.26 |
-40:12:25.4 |
HIP 89881 |
11.68 |
| 2026-10-04 12:00 |
18:19:33.18 |
-40:11:13.9 |
HIP 89881 |
11.46 |
| 2026-10-05 00:00 |
18:19:37.34 |
-40:10:02.6 |
HIP 89881 |
11.37 |
| 2026-10-05 12:00 |
18:19:41.73 |
-40:08:51.4 |
HIP 89881 |
11.42 |
| 2026-10-06 00:00 |
18:19:46.35 |
-40:07:40.5 |
HIP 89881 |
11.63 |
| 2026-10-06 12:00 |
18:19:51.20 |
-40:06:29.6 |
HIP 89881 |
11.99 |
| 2026-10-07 00:00 |
18:19:56.28 |
-40:05:19.0 |
HIP 89881 |
12.49 |
| 2026-10-07 12:00 |
18:20:01.59 |
-40:04:08.6 |
HIP 89881 |
13.14 |
| 2026-10-08 00:00 |
18:20:07.12 |
-40:02:58.3 |
HIP 89881 |
13.91 |
| 2026-10-08 12:00 |
18:20:12.88 |
-40:01:48.2 |
HIP 89881 |
14.80 |
| 2026-10-09 00:00 |
18:20:18.86 |
-40:00:38.3 |
HIP 89881 |
15.79 |
| 2026-10-09 12:00 |
18:20:25.06 |
-39:59:28.6 |
HIP 89881 |
16.88 |
| 2026-10-10 00:00 |
18:20:31.48 |
-39:58:19.1 |
HIP 89881 |
18.06 |
| 2026-10-10 12:00 |
18:20:38.13 |
-39:57:09.9 |
HIP 89881 |
19.31 |
| 2026-10-11 00:00 |
18:20:44.99 |
-39:56:00.8 |
HIP 89881 |
20.64 |