| Parameter |
Value |
| Designation |
C/1994 T1 (Machholz) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1994-10-02T13:22:18.399360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:47Z |
| Obs used |
344 |
| NEO |
- |
| M1 |
10.400 |
| K1 |
5.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1994-11-26.0000000 |
| e |
0.99949492 |
| q (au) |
1.845392 |
| a (au) |
3653.643991 |
| i (deg) |
101.737600 |
| Ω (om, deg) |
249.943625 |
| ω (w, deg) |
142.784278 |
| M (ma, deg) |
0.000243 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.712 + 3.102\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.712 |
| n |
3.102 |
| gf |
1.000 |
| gb |
-0.544 |
| 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) |
| 2026-07-29 00:00 |
17:19:03.32 |
-80:25:33.9 |
HIP 85301 |
22.00 |
| 2026-07-29 12:00 |
17:18:54.20 |
-80:25:12.4 |
HIP 85301 |
22.52 |
| 2026-07-30 00:00 |
17:18:45.18 |
-80:24:50.7 |
HIP 85301 |
23.04 |
| 2026-07-30 12:00 |
17:18:36.25 |
-80:24:28.9 |
HIP 85301 |
23.56 |
| 2026-07-31 00:00 |
17:18:27.40 |
-80:24:06.9 |
HIP 84180 |
23.66 |
| 2026-07-31 12:00 |
17:18:18.65 |
-80:23:44.8 |
HIP 84180 |
23.14 |
| 2026-08-01 00:00 |
17:18:10.00 |
-80:23:22.5 |
HIP 84180 |
22.63 |
| 2026-08-01 12:00 |
17:18:01.43 |
-80:23:00.0 |
HIP 84180 |
22.11 |
| 2026-08-02 00:00 |
17:17:52.96 |
-80:22:37.4 |
HIP 84180 |
21.59 |
| 2026-08-02 12:00 |
17:17:44.58 |
-80:22:14.6 |
HIP 84180 |
21.08 |
| 2026-08-03 00:00 |
17:17:36.30 |
-80:21:51.7 |
HIP 84180 |
20.56 |
| 2026-08-03 12:00 |
17:17:28.11 |
-80:21:28.7 |
HIP 84180 |
20.05 |
| 2026-08-04 00:00 |
17:17:20.02 |
-80:21:05.5 |
HIP 84180 |
19.53 |
| 2026-08-04 12:00 |
17:17:12.03 |
-80:20:42.1 |
HIP 84180 |
19.02 |
| 2026-08-05 00:00 |
17:17:04.13 |
-80:20:18.6 |
HIP 84180 |
18.51 |
| 2026-08-05 12:00 |
17:16:56.33 |
-80:19:55.0 |
HIP 84180 |
17.99 |
| 2026-08-06 00:00 |
17:16:48.62 |
-80:19:31.2 |
HIP 84180 |
17.48 |
| 2026-08-06 12:00 |
17:16:41.02 |
-80:19:07.3 |
HIP 84180 |
16.97 |
| 2026-08-07 00:00 |
17:16:33.51 |
-80:18:43.3 |
HIP 84180 |
16.46 |
| 2026-08-07 12:00 |
17:16:26.10 |
-80:18:19.1 |
HIP 84180 |
15.95 |
| 2026-08-08 00:00 |
17:16:18.79 |
-80:17:54.8 |
HIP 84180 |
15.44 |
| 2026-08-08 12:00 |
17:16:11.59 |
-80:17:30.3 |
HIP 84180 |
14.94 |
| 2026-08-09 00:00 |
17:16:04.48 |
-80:17:05.8 |
HIP 84180 |
14.43 |
| 2026-08-09 12:00 |
17:15:57.47 |
-80:16:41.1 |
HIP 84180 |
13.93 |
| 2026-08-10 00:00 |
17:15:50.57 |
-80:16:16.3 |
HIP 84180 |
13.42 |
| 2026-08-10 12:00 |
17:15:43.76 |
-80:15:51.3 |
HIP 84180 |
12.92 |
| 2026-08-11 00:00 |
17:15:37.06 |
-80:15:26.3 |
HIP 84180 |
12.42 |
| 2026-08-11 12:00 |
17:15:30.46 |
-80:15:01.1 |
HIP 84180 |
11.92 |
| 2026-08-12 00:00 |
17:15:23.96 |
-80:14:35.8 |
HIP 84180 |
11.42 |
| 2026-08-12 12:00 |
17:15:17.57 |
-80:14:10.4 |
HIP 84180 |
10.92 |
| 2026-08-13 00:00 |
17:15:11.28 |
-80:13:44.9 |
HIP 84180 |
10.42 |
| 2026-08-13 12:00 |
17:15:05.10 |
-80:13:19.3 |
HIP 84180 |
9.93 |
| 2026-08-14 00:00 |
17:14:59.02 |
-80:12:53.6 |
HIP 84180 |
9.44 |
| 2026-08-14 12:00 |
17:14:53.04 |
-80:12:27.8 |
HIP 84180 |
8.95 |
| 2026-08-15 00:00 |
17:14:47.17 |
-80:12:01.9 |
HIP 84180 |
8.47 |
| 2026-08-15 12:00 |
17:14:41.41 |
-80:11:35.9 |
HIP 84180 |
7.99 |
| 2026-08-16 00:00 |
17:14:35.75 |
-80:11:09.8 |
HIP 84180 |
7.51 |
| 2026-08-16 12:00 |
17:14:30.19 |
-80:10:43.6 |
HIP 84180 |
7.04 |
| 2026-08-17 00:00 |
17:14:24.74 |
-80:10:17.3 |
HIP 84180 |
6.57 |
| 2026-08-17 12:00 |
17:14:19.40 |
-80:09:50.9 |
HIP 84180 |
6.11 |
| 2026-08-18 00:00 |
17:14:14.16 |
-80:09:24.4 |
HIP 84180 |
5.66 |
| 2026-08-18 12:00 |
17:14:09.03 |
-80:08:57.9 |
HIP 84180 |
5.22 |
| 2026-08-19 00:00 |
17:14:04.00 |
-80:08:31.2 |
HIP 84180 |
4.79 |