| 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) |
| 2026-05-12 00:00 |
19:53:35.55 |
-37:47:50.6 |
HIP 97829 |
12.59 |
| 2026-05-12 12:00 |
19:53:26.40 |
-37:50:04.3 |
HIP 97829 |
12.97 |
| 2026-05-13 00:00 |
19:53:17.00 |
-37:52:18.5 |
HIP 97829 |
13.93 |
| 2026-05-13 12:00 |
19:53:07.34 |
-37:54:33.2 |
HIP 97829 |
15.38 |
| 2026-05-14 00:00 |
19:52:57.43 |
-37:56:48.4 |
HIP 97829 |
17.22 |
| 2026-05-14 12:00 |
19:52:47.26 |
-37:59:04.0 |
HIP 97829 |
19.35 |
| 2026-05-15 00:00 |
19:52:36.84 |
-38:01:20.0 |
HIP 97829 |
21.71 |
| 2026-05-15 12:00 |
19:52:26.16 |
-38:03:36.5 |
HIP 97691 |
19.82 |
| 2026-05-16 00:00 |
19:52:15.22 |
-38:05:53.4 |
HIP 97691 |
16.68 |
| 2026-05-16 12:00 |
19:52:04.02 |
-38:08:10.7 |
HIP 97691 |
13.51 |
| 2026-05-17 00:00 |
19:51:52.57 |
-38:10:28.3 |
HIP 97691 |
10.30 |
| 2026-05-17 12:00 |
19:51:40.85 |
-38:12:46.4 |
HIP 97691 |
7.05 |
| 2026-05-18 00:00 |
19:51:28.88 |
-38:15:04.8 |
HIP 97691 |
3.76 |
| 2026-05-18 12:00 |
19:51:16.65 |
-38:17:23.5 |
HIP 97691 |
0.48 |
| 2026-05-19 00:00 |
19:51:04.17 |
-38:19:42.6 |
HIP 97691 |
2.96 |
| 2026-05-19 12:00 |
19:50:51.42 |
-38:22:02.0 |
HIP 97691 |
6.37 |
| 2026-05-20 00:00 |
19:50:38.42 |
-38:24:21.6 |
HIP 97691 |
9.82 |
| 2026-05-20 12:00 |
19:50:25.15 |
-38:26:41.6 |
HIP 97691 |
13.31 |
| 2026-05-21 00:00 |
19:50:11.63 |
-38:29:01.8 |
HIP 97691 |
16.84 |
| 2026-05-21 12:00 |
19:49:57.85 |
-38:31:22.2 |
HIP 97691 |
20.40 |
| 2026-05-22 00:00 |
19:49:43.82 |
-38:33:42.9 |
HIP 97691 |
24.01 |
| 2026-05-22 12:00 |
19:49:29.53 |
-38:36:03.7 |
HIP 97691 |
27.66 |
| 2026-05-23 00:00 |
19:49:14.97 |
-38:38:24.8 |
HIP 97691 |
31.34 |
| 2026-05-23 12:00 |
19:49:00.17 |
-38:40:46.0 |
HIP 97691 |
35.07 |
| 2026-05-24 00:00 |
19:48:45.10 |
-38:43:07.4 |
HIP 97691 |
38.83 |
| 2026-05-24 12:00 |
19:48:29.78 |
-38:45:28.9 |
HIP 97218 |
39.11 |
| 2026-05-25 00:00 |
19:48:14.21 |
-38:47:50.6 |
HIP 97218 |
37.54 |
| 2026-05-25 12:00 |
19:47:58.38 |
-38:50:12.4 |
HIP 97218 |
36.27 |
| 2026-05-26 00:00 |
19:47:42.29 |
-38:52:34.2 |
HIP 97218 |
35.36 |
| 2026-05-26 12:00 |
19:47:25.95 |
-38:54:56.1 |
HIP 97302 |
32.35 |
| 2026-05-27 00:00 |
19:47:09.36 |
-38:57:18.1 |
HIP 97302 |
29.16 |
| 2026-05-27 12:00 |
19:46:52.51 |
-38:59:40.1 |
HIP 97302 |
26.17 |
| 2026-05-28 00:00 |
19:46:35.40 |
-39:02:02.1 |
HIP 97302 |
23.51 |
| 2026-05-28 12:00 |
19:46:18.05 |
-39:04:24.1 |
HIP 97302 |
21.29 |
| 2026-05-29 00:00 |
19:46:00.44 |
-39:06:46.1 |
HIP 97302 |
19.71 |
| 2026-05-29 12:00 |
19:45:42.58 |
-39:09:08.0 |
HIP 97302 |
18.95 |
| 2026-05-30 00:00 |
19:45:24.47 |
-39:11:29.9 |
HIP 97302 |
19.13 |
| 2026-05-30 12:00 |
19:45:06.12 |
-39:13:51.7 |
HIP 97112 |
16.07 |
| 2026-05-31 00:00 |
19:44:47.51 |
-39:16:13.4 |
HIP 97112 |
11.92 |
| 2026-05-31 12:00 |
19:44:28.65 |
-39:18:34.9 |
HIP 97112 |
7.90 |
| 2026-06-01 00:00 |
19:44:09.54 |
-39:20:56.4 |
HIP 97112 |
4.54 |
| 2026-06-01 12:00 |
19:43:50.19 |
-39:23:17.6 |
HIP 97112 |
4.19 |
| 2026-06-02 00:00 |
19:43:30.59 |
-39:25:38.7 |
HIP 97112 |
7.36 |