| Parameter |
Value |
| Designation |
C/1988 P1 (Machholz) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-09-17T13:37:56.176320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
56 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1988-08-19.0000000 |
| e |
0.99999939 |
| q (au) |
0.164552 |
| a (au) |
268133.697775 |
| i (deg) |
40.198656 |
| Ω (om, deg) |
167.727558 |
| ω (w, deg) |
349.037996 |
| M (ma, deg) |
360.000000 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.848 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.848 |
| n |
2.000 |
| gf |
0.982 |
| gb |
-1.000 |
| k |
0.950 |
| 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 |
22:12:12.04 |
+00:31:40.6 |
HIP 109709 |
24.18 |
| 2026-07-29 12:00 |
22:12:10.47 |
+00:31:34.1 |
HIP 109709 |
24.38 |
| 2026-07-30 00:00 |
22:12:08.89 |
+00:31:27.4 |
HIP 109709 |
24.59 |
| 2026-07-30 12:00 |
22:12:07.31 |
+00:31:20.7 |
HIP 109709 |
24.80 |
| 2026-07-31 00:00 |
22:12:05.72 |
+00:31:13.9 |
HIP 109709 |
25.02 |
| 2026-07-31 12:00 |
22:12:04.13 |
+00:31:07.0 |
HIP 109709 |
25.24 |
| 2026-08-01 00:00 |
22:12:02.52 |
+00:31:00.1 |
HIP 109709 |
25.47 |
| 2026-08-01 12:00 |
22:12:00.92 |
+00:30:53.1 |
HIP 109709 |
25.71 |
| 2026-08-02 00:00 |
22:11:59.30 |
+00:30:46.0 |
HIP 109709 |
25.94 |
| 2026-08-02 12:00 |
22:11:57.68 |
+00:30:38.8 |
HIP 109709 |
26.19 |
| 2026-08-03 00:00 |
22:11:56.06 |
+00:30:31.6 |
HIP 109709 |
26.44 |
| 2026-08-03 12:00 |
22:11:54.43 |
+00:30:24.2 |
HIP 109709 |
26.69 |
| 2026-08-04 00:00 |
22:11:52.80 |
+00:30:16.8 |
HIP 109709 |
26.95 |
| 2026-08-04 12:00 |
22:11:51.16 |
+00:30:09.4 |
HIP 109709 |
27.21 |
| 2026-08-05 00:00 |
22:11:49.51 |
+00:30:01.8 |
HIP 109709 |
27.48 |
| 2026-08-05 12:00 |
22:11:47.86 |
+00:29:54.2 |
HIP 109709 |
27.75 |
| 2026-08-06 00:00 |
22:11:46.21 |
+00:29:46.5 |
HIP 109709 |
28.02 |
| 2026-08-06 12:00 |
22:11:44.55 |
+00:29:38.7 |
HIP 109709 |
28.30 |
| 2026-08-07 00:00 |
22:11:42.88 |
+00:29:30.9 |
HIP 109709 |
28.59 |
| 2026-08-07 12:00 |
22:11:41.22 |
+00:29:23.0 |
HIP 109709 |
28.87 |
| 2026-08-08 00:00 |
22:11:39.54 |
+00:29:15.0 |
HIP 109709 |
29.17 |
| 2026-08-08 12:00 |
22:11:37.87 |
+00:29:07.0 |
HIP 109709 |
29.46 |
| 2026-08-09 00:00 |
22:11:36.19 |
+00:28:58.9 |
HIP 109709 |
29.76 |
| 2026-08-09 12:00 |
22:11:34.50 |
+00:28:50.7 |
HIP 109709 |
30.07 |
| 2026-08-10 00:00 |
22:11:32.81 |
+00:28:42.4 |
HIP 109709 |
30.37 |
| 2026-08-10 12:00 |
22:11:31.12 |
+00:28:34.1 |
HIP 109709 |
30.68 |
| 2026-08-11 00:00 |
22:11:29.42 |
+00:28:25.7 |
HIP 109709 |
31.00 |
| 2026-08-11 12:00 |
22:11:27.73 |
+00:28:17.3 |
HIP 109709 |
31.32 |
| 2026-08-12 00:00 |
22:11:26.02 |
+00:28:08.8 |
HIP 109709 |
31.64 |
| 2026-08-12 12:00 |
22:11:24.32 |
+00:28:00.2 |
HIP 109709 |
31.96 |
| 2026-08-13 00:00 |
22:11:22.61 |
+00:27:51.6 |
HIP 109709 |
32.29 |
| 2026-08-13 12:00 |
22:11:20.90 |
+00:27:42.8 |
HIP 109709 |
32.62 |
| 2026-08-14 00:00 |
22:11:19.18 |
+00:27:34.1 |
HIP 109709 |
32.96 |
| 2026-08-14 12:00 |
22:11:17.47 |
+00:27:25.2 |
HIP 109709 |
33.30 |
| 2026-08-15 00:00 |
22:11:15.75 |
+00:27:16.3 |
HIP 109709 |
33.64 |
| 2026-08-15 12:00 |
22:11:14.03 |
+00:27:07.4 |
HIP 109709 |
33.98 |
| 2026-08-16 00:00 |
22:11:12.30 |
+00:26:58.4 |
HIP 109709 |
34.32 |
| 2026-08-16 12:00 |
22:11:10.58 |
+00:26:49.3 |
HIP 109709 |
34.67 |
| 2026-08-17 00:00 |
22:11:08.85 |
+00:26:40.2 |
HIP 109709 |
35.02 |
| 2026-08-17 12:00 |
22:11:07.12 |
+00:26:31.0 |
HIP 109709 |
35.38 |
| 2026-08-18 00:00 |
22:11:05.39 |
+00:26:21.7 |
HIP 109709 |
35.73 |
| 2026-08-18 12:00 |
22:11:03.66 |
+00:26:12.4 |
HIP 109709 |
36.09 |
| 2026-08-19 00:00 |
22:11:01.92 |
+00:26:03.1 |
HIP 109302 |
35.83 |