| Parameter |
Value |
| Designation |
C/2018 R5 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-01-09T23:30:34.822080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:46Z |
| Obs used |
187 |
| NEO |
- |
| M1 |
14.400 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2018-09-08T05:36:38.592000Z |
| Discovery magnitude (MPC) |
19.00 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-09-19.0000000 |
| e |
0.84156810 |
| q (au) |
3.621229 |
| a (au) |
22.856691 |
| i (deg) |
103.758081 |
| Ω (om, deg) |
171.141565 |
| ω (w, deg) |
178.011726 |
| M (ma, deg) |
358.980977 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.984 + 2.626\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.984 |
| n |
2.626 |
| gf |
0.814 |
| gb |
-0.918 |
| k |
0.981 |
| δ90 |
1.000 |
| 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 |
10:39:47.68 |
-46:22:35.7 |
HIP 52245 |
18.97 |
| 2026-03-26 12:00 |
10:39:38.79 |
-46:21:11.6 |
HIP 52245 |
18.35 |
| 2026-03-27 00:00 |
10:39:29.94 |
-46:19:46.7 |
HIP 52031 |
17.55 |
| 2026-03-27 12:00 |
10:39:21.16 |
-46:18:21.3 |
HIP 52031 |
15.81 |
| 2026-03-28 00:00 |
10:39:12.42 |
-46:16:55.2 |
HIP 52031 |
14.17 |
| 2026-03-28 12:00 |
10:39:03.74 |
-46:15:28.4 |
HIP 52031 |
12.66 |
| 2026-03-29 00:00 |
10:38:55.11 |
-46:14:01.1 |
HIP 52031 |
11.35 |
| 2026-03-29 12:00 |
10:38:46.54 |
-46:12:33.1 |
HIP 52031 |
10.30 |
| 2026-03-30 00:00 |
10:38:38.02 |
-46:11:04.5 |
HIP 52031 |
9.62 |
| 2026-03-30 12:00 |
10:38:29.56 |
-46:09:35.3 |
HIP 52031 |
9.37 |
| 2026-03-31 00:00 |
10:38:21.16 |
-46:08:05.5 |
HIP 52031 |
9.59 |
| 2026-03-31 12:00 |
10:38:12.81 |
-46:06:35.1 |
HIP 52031 |
10.26 |
| 2026-04-01 00:00 |
10:38:04.53 |
-46:05:04.2 |
HIP 52012 |
11.06 |
| 2026-04-01 12:00 |
10:37:56.30 |
-46:03:32.7 |
HIP 52012 |
9.08 |
| 2026-04-02 00:00 |
10:37:48.13 |
-46:02:00.6 |
HIP 52012 |
7.15 |
| 2026-04-02 12:00 |
10:37:40.02 |
-46:00:27.9 |
HIP 52012 |
5.33 |
| 2026-04-03 00:00 |
10:37:31.97 |
-45:58:54.7 |
HIP 52012 |
3.80 |
| 2026-04-03 12:00 |
10:37:23.99 |
-45:57:20.9 |
HIP 52012 |
3.01 |
| 2026-04-04 00:00 |
10:37:16.06 |
-45:55:46.6 |
HIP 52012 |
3.52 |
| 2026-04-04 12:00 |
10:37:08.20 |
-45:54:11.8 |
HIP 52012 |
4.93 |
| 2026-04-05 00:00 |
10:37:00.40 |
-45:52:36.5 |
HIP 52012 |
6.70 |
| 2026-04-05 12:00 |
10:36:52.67 |
-45:51:00.6 |
HIP 52012 |
8.62 |
| 2026-04-06 00:00 |
10:36:45.00 |
-45:49:24.2 |
HIP 52012 |
10.59 |
| 2026-04-06 12:00 |
10:36:37.39 |
-45:47:47.4 |
HIP 52012 |
12.60 |
| 2026-04-07 00:00 |
10:36:29.85 |
-45:46:10.0 |
HIP 52012 |
14.63 |
| 2026-04-07 12:00 |
10:36:22.38 |
-45:44:32.1 |
HIP 51805 |
16.41 |
| 2026-04-08 00:00 |
10:36:14.97 |
-45:42:53.8 |
HIP 51805 |
16.39 |
| 2026-04-08 12:00 |
10:36:07.63 |
-45:41:15.0 |
HIP 51805 |
16.65 |
| 2026-04-09 00:00 |
10:36:00.36 |
-45:39:35.7 |
HIP 51976 |
16.55 |
| 2026-04-09 12:00 |
10:35:53.16 |
-45:37:56.0 |
HIP 51976 |
16.56 |
| 2026-04-10 00:00 |
10:35:46.02 |
-45:36:15.9 |
HIP 51976 |
16.83 |
| 2026-04-10 12:00 |
10:35:38.96 |
-45:34:35.3 |
HIP 51976 |
17.33 |
| 2026-04-11 00:00 |
10:35:31.96 |
-45:32:54.2 |
HIP 51976 |
18.04 |
| 2026-04-11 12:00 |
10:35:25.04 |
-45:31:12.8 |
HIP 51730 |
18.68 |
| 2026-04-12 00:00 |
10:35:18.18 |
-45:29:30.9 |
HIP 51730 |
19.16 |
| 2026-04-12 12:00 |
10:35:11.40 |
-45:27:48.6 |
HIP 51730 |
19.86 |
| 2026-04-13 00:00 |
10:35:04.69 |
-45:26:05.9 |
HIP 51730 |
20.75 |
| 2026-04-13 12:00 |
10:34:58.05 |
-45:24:22.8 |
HIP 51730 |
21.82 |
| 2026-04-14 00:00 |
10:34:51.49 |
-45:22:39.4 |
HIP 51730 |
23.03 |
| 2026-04-14 12:00 |
10:34:45.00 |
-45:20:55.6 |
HIP 51730 |
24.37 |
| 2026-04-15 00:00 |
10:34:38.58 |
-45:19:11.4 |
HIP 51730 |
25.81 |
| 2026-04-15 12:00 |
10:34:32.24 |
-45:17:26.8 |
HIP 51730 |
27.34 |
| 2026-04-16 00:00 |
10:34:25.97 |
-45:15:41.9 |
HIP 51561 |
28.67 |