C/2018 DO4 (Lemmon)
| Parameter |
Value |
| Designation |
C/2018 DO4 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-08-18T09:51:21.291840Z |
| Orbit solution date (soln_date, UTC) |
2022-06-28T08:33:35Z |
| Obs used |
660 |
| NEO |
- |
| M1 |
13.200 |
| K1 |
6.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-07-09.0000000 |
| e |
0.90695413 |
| q (au) |
2.405953 |
| a (au) |
25.857709 |
| i (deg) |
160.474821 |
| Ω (om, deg) |
251.132876 |
| ω (w, deg) |
175.974733 |
| M (ma, deg) |
359.697089 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.922 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.922 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.901 |
| k |
1.000 |
| 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) |
| 2026-02-03 00:00 |
19:49:44.17 |
-33:31:25.9 |
HIP 97529 |
11.94 |
| 2026-02-03 12:00 |
19:49:51.03 |
-33:31:14.3 |
HIP 97529 |
12.78 |
| 2026-02-04 00:00 |
19:49:57.87 |
-33:31:02.9 |
HIP 97529 |
13.71 |
| 2026-02-04 12:00 |
19:50:04.68 |
-33:30:51.8 |
HIP 97529 |
14.72 |
| 2026-02-05 00:00 |
19:50:11.47 |
-33:30:40.9 |
HIP 97529 |
15.79 |
| 2026-02-05 12:00 |
19:50:18.23 |
-33:30:30.2 |
HIP 97529 |
16.90 |
| 2026-02-06 00:00 |
19:50:24.97 |
-33:30:19.7 |
HIP 97529 |
18.05 |
| 2026-02-06 12:00 |
19:50:31.68 |
-33:30:09.4 |
HIP 97529 |
19.23 |
| 2026-02-07 00:00 |
19:50:38.37 |
-33:29:59.4 |
HIP 97529 |
20.43 |
| 2026-02-07 12:00 |
19:50:45.03 |
-33:29:49.6 |
HIP 97529 |
21.65 |
| 2026-02-08 00:00 |
19:50:51.66 |
-33:29:40.1 |
HIP 97529 |
22.88 |
| 2026-02-08 12:00 |
19:50:58.26 |
-33:29:30.7 |
HIP 97529 |
24.12 |
| 2026-02-09 00:00 |
19:51:04.83 |
-33:29:21.6 |
HIP 97529 |
25.37 |
| 2026-02-09 12:00 |
19:51:11.38 |
-33:29:12.7 |
HIP 97529 |
26.63 |
| 2026-02-10 00:00 |
19:51:17.89 |
-33:29:04.1 |
HIP 97529 |
27.89 |
| 2026-02-10 12:00 |
19:51:24.38 |
-33:28:55.7 |
HIP 97529 |
29.15 |
| 2026-02-11 00:00 |
19:51:30.83 |
-33:28:47.5 |
HIP 97529 |
30.41 |
| 2026-02-11 12:00 |
19:51:37.26 |
-33:28:39.6 |
HIP 97529 |
31.67 |
| 2026-02-12 00:00 |
19:51:43.65 |
-33:28:31.9 |
HIP 97529 |
32.93 |
| 2026-02-12 12:00 |
19:51:50.01 |
-33:28:24.4 |
HIP 97529 |
34.19 |
| 2026-02-13 00:00 |
19:51:56.34 |
-33:28:17.2 |
HIP 97529 |
35.45 |
| 2026-02-13 12:00 |
19:52:02.63 |
-33:28:10.2 |
HIP 97977 |
35.27 |
| 2026-02-14 00:00 |
19:52:08.89 |
-33:28:03.4 |
HIP 97977 |
33.99 |
| 2026-02-14 12:00 |
19:52:15.12 |
-33:27:56.9 |
HIP 97977 |
32.73 |
| 2026-02-15 00:00 |
19:52:21.31 |
-33:27:50.6 |
HIP 97977 |
31.48 |
| 2026-02-15 12:00 |
19:52:27.47 |
-33:27:44.6 |
HIP 97977 |
30.23 |
| 2026-02-16 00:00 |
19:52:33.59 |
-33:27:38.8 |
HIP 97977 |
29.00 |
| 2026-02-16 12:00 |
19:52:39.67 |
-33:27:33.3 |
HIP 97977 |
27.79 |
| 2026-02-17 00:00 |
19:52:45.72 |
-33:27:28.0 |
HIP 97977 |
26.59 |
| 2026-02-17 12:00 |
19:52:51.73 |
-33:27:22.9 |
HIP 97977 |
25.40 |
| 2026-02-18 00:00 |
19:52:57.70 |
-33:27:18.1 |
HIP 97977 |
24.23 |
| 2026-02-18 12:00 |
19:53:03.64 |
-33:27:13.6 |
HIP 97977 |
23.08 |
| 2026-02-19 00:00 |
19:53:09.53 |
-33:27:09.3 |
HIP 97977 |
21.94 |
| 2026-02-19 12:00 |
19:53:15.39 |
-33:27:05.2 |
HIP 97977 |
20.83 |
| 2026-02-20 00:00 |
19:53:21.20 |
-33:27:01.4 |
HIP 97977 |
19.73 |
| 2026-02-20 12:00 |
19:53:26.98 |
-33:26:57.8 |
HIP 97977 |
18.66 |
| 2026-02-21 00:00 |
19:53:32.71 |
-33:26:54.5 |
HIP 97977 |
17.62 |
| 2026-02-21 12:00 |
19:53:38.40 |
-33:26:51.5 |
HIP 97977 |
16.61 |
| 2026-02-22 00:00 |
19:53:44.05 |
-33:26:48.7 |
HIP 97977 |
15.64 |
| 2026-02-22 12:00 |
19:53:49.66 |
-33:26:46.1 |
HIP 97977 |
14.70 |
| 2026-02-23 00:00 |
19:53:55.23 |
-33:26:43.8 |
HIP 97977 |
13.81 |
| 2026-02-23 12:00 |
19:54:00.75 |
-33:26:41.7 |
HIP 97977 |
12.98 |
| 2026-02-24 00:00 |
19:54:06.23 |
-33:26:39.9 |
HIP 97977 |
12.20 |