| 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) |
| 2026-03-26 00:00 |
22:12:33.12 |
+00:15:23.4 |
HIP 109709 |
11.82 |
| 2026-03-26 12:00 |
22:12:34.59 |
+00:15:34.4 |
HIP 109709 |
11.47 |
| 2026-03-27 00:00 |
22:12:36.05 |
+00:15:45.5 |
HIP 109709 |
11.12 |
| 2026-03-27 12:00 |
22:12:37.50 |
+00:15:56.5 |
HIP 109709 |
10.79 |
| 2026-03-28 00:00 |
22:12:38.94 |
+00:16:07.5 |
HIP 109709 |
10.45 |
| 2026-03-28 12:00 |
22:12:40.38 |
+00:16:18.5 |
HIP 109709 |
10.13 |
| 2026-03-29 00:00 |
22:12:41.81 |
+00:16:29.5 |
HIP 109709 |
9.81 |
| 2026-03-29 12:00 |
22:12:43.22 |
+00:16:40.5 |
HIP 109709 |
9.51 |
| 2026-03-30 00:00 |
22:12:44.63 |
+00:16:51.5 |
HIP 109709 |
9.21 |
| 2026-03-30 12:00 |
22:12:46.03 |
+00:17:02.5 |
HIP 109709 |
8.92 |
| 2026-03-31 00:00 |
22:12:47.42 |
+00:17:13.4 |
HIP 109709 |
8.64 |
| 2026-03-31 12:00 |
22:12:48.80 |
+00:17:24.4 |
HIP 109709 |
8.38 |
| 2026-04-01 00:00 |
22:12:50.17 |
+00:17:35.3 |
HIP 109709 |
8.12 |
| 2026-04-01 12:00 |
22:12:51.54 |
+00:17:46.2 |
HIP 109709 |
7.88 |
| 2026-04-02 00:00 |
22:12:52.89 |
+00:17:57.1 |
HIP 109709 |
7.65 |
| 2026-04-02 12:00 |
22:12:54.23 |
+00:18:08.0 |
HIP 109709 |
7.44 |
| 2026-04-03 00:00 |
22:12:55.57 |
+00:18:18.8 |
HIP 109709 |
7.24 |
| 2026-04-03 12:00 |
22:12:56.89 |
+00:18:29.7 |
HIP 109709 |
7.06 |
| 2026-04-04 00:00 |
22:12:58.21 |
+00:18:40.5 |
HIP 109709 |
6.90 |
| 2026-04-04 12:00 |
22:12:59.51 |
+00:18:51.3 |
HIP 109709 |
6.75 |
| 2026-04-05 00:00 |
22:13:00.80 |
+00:19:02.1 |
HIP 109709 |
6.63 |
| 2026-04-05 12:00 |
22:13:02.09 |
+00:19:12.8 |
HIP 109709 |
6.52 |
| 2026-04-06 00:00 |
22:13:03.36 |
+00:19:23.6 |
HIP 109709 |
6.44 |
| 2026-04-06 12:00 |
22:13:04.63 |
+00:19:34.3 |
HIP 109709 |
6.37 |
| 2026-04-07 00:00 |
22:13:05.88 |
+00:19:45.0 |
HIP 109709 |
6.33 |
| 2026-04-07 12:00 |
22:13:07.12 |
+00:19:55.6 |
HIP 109709 |
6.31 |
| 2026-04-08 00:00 |
22:13:08.36 |
+00:20:06.3 |
HIP 109709 |
6.31 |
| 2026-04-08 12:00 |
22:13:09.58 |
+00:20:16.9 |
HIP 109709 |
6.34 |
| 2026-04-09 00:00 |
22:13:10.79 |
+00:20:27.4 |
HIP 109709 |
6.38 |
| 2026-04-09 12:00 |
22:13:11.99 |
+00:20:38.0 |
HIP 109709 |
6.44 |
| 2026-04-10 00:00 |
22:13:13.18 |
+00:20:48.5 |
HIP 109709 |
6.52 |
| 2026-04-10 12:00 |
22:13:14.36 |
+00:20:59.0 |
HIP 109709 |
6.61 |
| 2026-04-11 00:00 |
22:13:15.52 |
+00:21:09.5 |
HIP 109709 |
6.73 |
| 2026-04-11 12:00 |
22:13:16.68 |
+00:21:19.9 |
HIP 109709 |
6.85 |
| 2026-04-12 00:00 |
22:13:17.83 |
+00:21:30.3 |
HIP 109709 |
6.99 |
| 2026-04-12 12:00 |
22:13:18.96 |
+00:21:40.7 |
HIP 109709 |
7.15 |
| 2026-04-13 00:00 |
22:13:20.08 |
+00:21:51.0 |
HIP 109709 |
7.31 |
| 2026-04-13 12:00 |
22:13:21.19 |
+00:22:01.3 |
HIP 109709 |
7.49 |
| 2026-04-14 00:00 |
22:13:22.29 |
+00:22:11.6 |
HIP 109709 |
7.67 |
| 2026-04-14 12:00 |
22:13:23.38 |
+00:22:21.9 |
HIP 109709 |
7.86 |
| 2026-04-15 00:00 |
22:13:24.46 |
+00:22:32.1 |
HIP 109709 |
8.06 |
| 2026-04-15 12:00 |
22:13:25.52 |
+00:22:42.2 |
HIP 109709 |
8.27 |
| 2026-04-16 00:00 |
22:13:26.57 |
+00:22:52.3 |
HIP 109709 |
8.48 |