| Parameter |
Value |
| Designation |
C/1985 K1 (Machholz) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1985-06-28T17:43:33.605760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
30 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1985-06-19.0000000 |
| e |
1.00000000 |
| q (au) |
0.106250 |
| a (au) |
- |
| i (deg) |
16.276479 |
| Ω (om, deg) |
195.434274 |
| ω (w, deg) |
274.501133 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (9.225 + 3.309\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.225 |
| n |
3.309 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.800 |
| 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) |
| 2026-05-12 00:00 |
19:01:57.16 |
-06:13:18.5 |
HIP 93451 |
2.44 |
| 2026-05-12 12:00 |
19:01:56.12 |
-06:13:14.0 |
HIP 93451 |
2.34 |
| 2026-05-13 00:00 |
19:01:55.07 |
-06:13:09.6 |
HIP 93451 |
2.27 |
| 2026-05-13 12:00 |
19:01:54.00 |
-06:13:05.2 |
HIP 93451 |
2.23 |
| 2026-05-14 00:00 |
19:01:52.93 |
-06:13:00.9 |
HIP 93451 |
2.23 |
| 2026-05-14 12:00 |
19:01:51.84 |
-06:12:56.6 |
HIP 93451 |
2.26 |
| 2026-05-15 00:00 |
19:01:50.74 |
-06:12:52.4 |
HIP 93451 |
2.33 |
| 2026-05-15 12:00 |
19:01:49.62 |
-06:12:48.2 |
HIP 93451 |
2.44 |
| 2026-05-16 00:00 |
19:01:48.50 |
-06:12:44.1 |
HIP 93451 |
2.57 |
| 2026-05-16 12:00 |
19:01:47.36 |
-06:12:40.1 |
HIP 93451 |
2.73 |
| 2026-05-17 00:00 |
19:01:46.21 |
-06:12:36.1 |
HIP 93451 |
2.92 |
| 2026-05-17 12:00 |
19:01:45.06 |
-06:12:32.2 |
HIP 93451 |
3.12 |
| 2026-05-18 00:00 |
19:01:43.88 |
-06:12:28.4 |
HIP 93451 |
3.34 |
| 2026-05-18 12:00 |
19:01:42.70 |
-06:12:24.6 |
HIP 93451 |
3.58 |
| 2026-05-19 00:00 |
19:01:41.51 |
-06:12:20.8 |
HIP 93411 |
3.62 |
| 2026-05-19 12:00 |
19:01:40.30 |
-06:12:17.1 |
HIP 93411 |
3.31 |
| 2026-05-20 00:00 |
19:01:39.09 |
-06:12:13.5 |
HIP 93411 |
3.00 |
| 2026-05-20 12:00 |
19:01:37.86 |
-06:12:10.0 |
HIP 93411 |
2.69 |
| 2026-05-21 00:00 |
19:01:36.62 |
-06:12:06.5 |
HIP 93411 |
2.38 |
| 2026-05-21 12:00 |
19:01:35.37 |
-06:12:03.1 |
HIP 93411 |
2.06 |
| 2026-05-22 00:00 |
19:01:34.12 |
-06:11:59.7 |
HIP 93411 |
1.75 |
| 2026-05-22 12:00 |
19:01:32.85 |
-06:11:56.4 |
HIP 93411 |
1.43 |
| 2026-05-23 00:00 |
19:01:31.57 |
-06:11:53.1 |
HIP 93411 |
1.11 |
| 2026-05-23 12:00 |
19:01:30.28 |
-06:11:50.0 |
HIP 93411 |
0.79 |
| 2026-05-24 00:00 |
19:01:28.97 |
-06:11:46.8 |
HIP 93411 |
0.47 |
| 2026-05-24 12:00 |
19:01:27.66 |
-06:11:43.8 |
HIP 93411 |
0.20 |
| 2026-05-25 00:00 |
19:01:26.34 |
-06:11:40.8 |
HIP 93411 |
0.27 |
| 2026-05-25 12:00 |
19:01:25.01 |
-06:11:37.9 |
HIP 93411 |
0.58 |
| 2026-05-26 00:00 |
19:01:23.67 |
-06:11:35.0 |
HIP 93411 |
0.90 |
| 2026-05-26 12:00 |
19:01:22.32 |
-06:11:32.2 |
HIP 93411 |
1.24 |
| 2026-05-27 00:00 |
19:01:20.96 |
-06:11:29.5 |
HIP 93411 |
1.58 |
| 2026-05-27 12:00 |
19:01:19.59 |
-06:11:26.8 |
HIP 93411 |
1.92 |
| 2026-05-28 00:00 |
19:01:18.21 |
-06:11:24.2 |
HIP 93411 |
2.27 |
| 2026-05-28 12:00 |
19:01:16.83 |
-06:11:21.6 |
HIP 93411 |
2.61 |
| 2026-05-29 00:00 |
19:01:15.43 |
-06:11:19.1 |
HIP 93411 |
2.96 |
| 2026-05-29 12:00 |
19:01:14.02 |
-06:11:16.7 |
HIP 93411 |
3.31 |
| 2026-05-30 00:00 |
19:01:12.61 |
-06:11:14.4 |
HIP 93411 |
3.67 |
| 2026-05-30 12:00 |
19:01:11.18 |
-06:11:12.1 |
HIP 93411 |
4.02 |
| 2026-05-31 00:00 |
19:01:09.75 |
-06:11:09.8 |
HIP 93411 |
4.38 |
| 2026-05-31 12:00 |
19:01:08.31 |
-06:11:07.7 |
HIP 93411 |
4.74 |
| 2026-06-01 00:00 |
19:01:06.86 |
-06:11:05.6 |
HIP 93411 |
5.10 |
| 2026-06-01 12:00 |
19:01:05.40 |
-06:11:03.5 |
HIP 93411 |
5.47 |
| 2026-06-02 00:00 |
19:01:03.93 |
-06:11:01.6 |
HIP 93411 |
5.83 |