C/2018 R5 (Lemmon)
| 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) |
| 2026-02-03 00:00 |
10:56:33.59 |
-47:33:41.2 |
HIP 53436 |
6.94 |
| 2026-02-03 12:00 |
10:56:24.51 |
-47:33:44.7 |
HIP 53436 |
5.42 |
| 2026-02-04 00:00 |
10:56:15.38 |
-47:33:47.4 |
HIP 53436 |
3.89 |
| 2026-02-04 12:00 |
10:56:06.20 |
-47:33:49.2 |
HIP 53436 |
2.37 |
| 2026-02-05 00:00 |
10:55:56.98 |
-47:33:50.1 |
HIP 53436 |
0.97 |
| 2026-02-05 12:00 |
10:55:47.72 |
-47:33:50.1 |
HIP 53436 |
1.06 |
| 2026-02-06 00:00 |
10:55:38.40 |
-47:33:49.3 |
HIP 53436 |
2.50 |
| 2026-02-06 12:00 |
10:55:29.05 |
-47:33:47.5 |
HIP 53436 |
4.05 |
| 2026-02-07 00:00 |
10:55:19.65 |
-47:33:44.8 |
HIP 53436 |
5.62 |
| 2026-02-07 12:00 |
10:55:10.21 |
-47:33:41.2 |
HIP 53436 |
7.21 |
| 2026-02-08 00:00 |
10:55:00.72 |
-47:33:36.7 |
HIP 53322 |
7.47 |
| 2026-02-08 12:00 |
10:54:51.20 |
-47:33:31.3 |
HIP 53322 |
6.13 |
| 2026-02-09 00:00 |
10:54:41.63 |
-47:33:25.0 |
HIP 53322 |
4.95 |
| 2026-02-09 12:00 |
10:54:32.03 |
-47:33:17.8 |
HIP 53322 |
4.05 |
| 2026-02-10 00:00 |
10:54:22.39 |
-47:33:09.7 |
HIP 53322 |
3.68 |
| 2026-02-10 12:00 |
10:54:12.72 |
-47:33:00.6 |
HIP 53322 |
3.98 |
| 2026-02-11 00:00 |
10:54:03.00 |
-47:32:50.6 |
HIP 53322 |
4.85 |
| 2026-02-11 12:00 |
10:53:53.25 |
-47:32:39.7 |
HIP 53322 |
6.05 |
| 2026-02-12 00:00 |
10:53:43.47 |
-47:32:27.9 |
HIP 53322 |
7.43 |
| 2026-02-12 12:00 |
10:53:33.66 |
-47:32:15.2 |
HIP 53322 |
8.91 |
| 2026-02-13 00:00 |
10:53:23.81 |
-47:32:01.5 |
HIP 53322 |
10.44 |
| 2026-02-13 12:00 |
10:53:13.94 |
-47:31:46.9 |
HIP 53322 |
12.02 |
| 2026-02-14 00:00 |
10:53:04.03 |
-47:31:31.4 |
HIP 53322 |
13.62 |
| 2026-02-14 12:00 |
10:52:54.09 |
-47:31:14.9 |
HIP 53322 |
15.25 |
| 2026-02-15 00:00 |
10:52:44.13 |
-47:30:57.6 |
HIP 53322 |
16.90 |
| 2026-02-15 12:00 |
10:52:34.14 |
-47:30:39.2 |
HIP 53322 |
18.56 |
| 2026-02-16 00:00 |
10:52:24.12 |
-47:30:20.0 |
HIP 53322 |
20.23 |
| 2026-02-16 12:00 |
10:52:14.08 |
-47:29:59.8 |
HIP 53322 |
21.92 |
| 2026-02-17 00:00 |
10:52:04.02 |
-47:29:38.7 |
HIP 53322 |
23.61 |
| 2026-02-17 12:00 |
10:51:53.93 |
-47:29:16.6 |
HIP 53322 |
25.32 |
| 2026-02-18 00:00 |
10:51:43.83 |
-47:28:53.7 |
HIP 52953 |
25.81 |
| 2026-02-18 12:00 |
10:51:33.70 |
-47:28:29.7 |
HIP 52953 |
24.84 |
| 2026-02-19 00:00 |
10:51:23.55 |
-47:28:04.9 |
HIP 52953 |
23.96 |
| 2026-02-19 12:00 |
10:51:13.38 |
-47:27:39.1 |
HIP 52953 |
23.19 |
| 2026-02-20 00:00 |
10:51:03.20 |
-47:27:12.4 |
HIP 52953 |
22.55 |
| 2026-02-20 12:00 |
10:50:53.00 |
-47:26:44.7 |
HIP 52953 |
22.05 |
| 2026-02-21 00:00 |
10:50:42.79 |
-47:26:16.1 |
HIP 52953 |
21.69 |
| 2026-02-21 12:00 |
10:50:32.56 |
-47:25:46.6 |
HIP 52953 |
21.48 |
| 2026-02-22 00:00 |
10:50:22.32 |
-47:25:16.2 |
HIP 52953 |
21.45 |
| 2026-02-22 12:00 |
10:50:12.07 |
-47:24:44.8 |
HIP 52953 |
21.57 |
| 2026-02-23 00:00 |
10:50:01.81 |
-47:24:12.5 |
HIP 52953 |
21.86 |
| 2026-02-23 12:00 |
10:49:51.54 |
-47:23:39.3 |
HIP 52953 |
22.31 |
| 2026-02-24 00:00 |
10:49:41.26 |
-47:23:05.1 |
HIP 52953 |
22.91 |