| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
19:43:10.74 |
-39:27:59.6 |
HIP 97112 |
11.47 |
| 2026-06-03 00:00 |
19:42:50.65 |
-39:30:20.3 |
HIP 97112 |
15.83 |
| 2026-06-03 12:00 |
19:42:30.32 |
-39:32:40.8 |
HIP 97112 |
20.30 |
| 2026-06-04 00:00 |
19:42:09.74 |
-39:35:00.9 |
HIP 97112 |
24.85 |
| 2026-06-04 12:00 |
19:41:48.93 |
-39:37:20.8 |
HIP 96739 |
24.66 |
| 2026-06-05 00:00 |
19:41:27.87 |
-39:39:40.4 |
HIP 96719 |
21.12 |
| 2026-06-05 12:00 |
19:41:06.57 |
-39:41:59.7 |
HIP 96719 |
16.62 |
| 2026-06-06 00:00 |
19:40:45.03 |
-39:44:18.6 |
HIP 96719 |
12.25 |
| 2026-06-06 12:00 |
19:40:23.26 |
-39:46:37.2 |
HIP 96719 |
8.26 |
| 2026-06-07 00:00 |
19:40:01.25 |
-39:48:55.3 |
HIP 96716 |
4.81 |
| 2026-06-07 12:00 |
19:39:39.01 |
-39:51:13.1 |
HIP 96716 |
0.06 |
| 2026-06-08 00:00 |
19:39:16.54 |
-39:53:30.4 |
HIP 96716 |
4.92 |
| 2026-06-08 12:00 |
19:38:53.83 |
-39:55:47.3 |
HIP 96716 |
9.84 |
| 2026-06-09 00:00 |
19:38:30.90 |
-39:58:03.7 |
HIP 96716 |
14.79 |
| 2026-06-09 12:00 |
19:38:07.73 |
-40:00:19.6 |
HIP 96508 |
19.02 |
| 2026-06-10 00:00 |
19:37:44.34 |
-40:02:35.0 |
HIP 96508 |
19.02 |
| 2026-06-10 12:00 |
19:37:20.73 |
-40:04:49.8 |
HIP 96508 |
20.29 |
| 2026-06-11 00:00 |
19:36:56.89 |
-40:07:04.1 |
HIP 96508 |
22.64 |
| 2026-06-11 12:00 |
19:36:32.84 |
-40:09:17.8 |
HIP 96352 |
22.01 |
| 2026-06-12 00:00 |
19:36:08.56 |
-40:11:30.9 |
HIP 96391 |
18.68 |
| 2026-06-12 12:00 |
19:35:44.07 |
-40:13:43.3 |
HIP 96391 |
16.17 |
| 2026-06-13 00:00 |
19:35:19.36 |
-40:15:55.1 |
HIP 96391 |
15.12 |
| 2026-06-13 12:00 |
19:34:54.44 |
-40:18:06.2 |
HIP 96391 |
15.82 |
| 2026-06-14 00:00 |
19:34:29.31 |
-40:20:16.6 |
HIP 96391 |
18.12 |
| 2026-06-14 12:00 |
19:34:03.98 |
-40:22:26.3 |
HIP 96234 |
20.38 |
| 2026-06-15 00:00 |
19:33:38.43 |
-40:24:35.2 |
HIP 96234 |
23.23 |
| 2026-06-15 12:00 |
19:33:12.69 |
-40:26:43.4 |
HIP 96234 |
26.85 |
| 2026-06-16 00:00 |
19:32:46.75 |
-40:28:50.8 |
HIP 95954 |
22.82 |
| 2026-06-16 12:00 |
19:32:20.61 |
-40:30:57.3 |
HIP 95954 |
18.17 |
| 2026-06-17 00:00 |
19:31:54.27 |
-40:33:03.0 |
HIP 95954 |
14.01 |
| 2026-06-17 12:00 |
19:31:27.75 |
-40:35:07.9 |
HIP 95954 |
11.00 |
| 2026-06-18 00:00 |
19:31:01.04 |
-40:37:11.8 |
HIP 95954 |
10.23 |
| 2026-06-18 12:00 |
19:30:34.14 |
-40:39:14.9 |
HIP 95954 |
12.18 |
| 2026-06-19 00:00 |
19:30:07.06 |
-40:41:17.0 |
HIP 95789 |
15.82 |
| 2026-06-19 12:00 |
19:29:39.80 |
-40:43:18.2 |
HIP 95789 |
10.55 |
| 2026-06-20 00:00 |
19:29:12.36 |
-40:45:18.4 |
HIP 95789 |
5.80 |
| 2026-06-20 12:00 |
19:28:44.76 |
-40:47:17.6 |
HIP 95789 |
4.28 |
| 2026-06-21 00:00 |
19:28:16.98 |
-40:49:15.9 |
HIP 95714 |
2.31 |
| 2026-06-21 12:00 |
19:27:49.03 |
-40:51:13.0 |
HIP 95714 |
3.32 |
| 2026-06-22 00:00 |
19:27:20.92 |
-40:53:09.2 |
HIP 95648 |
3.03 |