| 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 · University of Arizona 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
$$
M_a = (14.981 + 2.627\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.981 |
| n |
2.627 |
| gf |
0.812 |
| 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) |
| 2026-09-20 00:00 |
10:54:38.56 |
-40:09:07.8 |
HIP 53307 |
6.18 |
| 2026-09-20 12:00 |
10:54:46.76 |
-40:09:38.7 |
HIP 53307 |
7.30 |
| 2026-09-21 00:00 |
10:54:54.94 |
-40:10:10.2 |
HIP 53307 |
8.59 |
| 2026-09-21 12:00 |
10:55:03.11 |
-40:10:42.1 |
HIP 53307 |
9.98 |
| 2026-09-22 00:00 |
10:55:11.25 |
-40:11:14.6 |
HIP 53307 |
11.44 |
| 2026-09-22 12:00 |
10:55:19.38 |
-40:11:47.6 |
HIP 53307 |
12.93 |
| 2026-09-23 00:00 |
10:55:27.48 |
-40:12:21.1 |
HIP 53307 |
14.46 |
| 2026-09-23 12:00 |
10:55:35.57 |
-40:12:55.1 |
HIP 53307 |
16.00 |
| 2026-09-24 00:00 |
10:55:43.63 |
-40:13:29.5 |
HIP 53307 |
17.56 |
| 2026-09-24 12:00 |
10:55:51.67 |
-40:14:04.5 |
HIP 53307 |
19.12 |
| 2026-09-25 00:00 |
10:55:59.69 |
-40:14:40.0 |
HIP 53307 |
20.70 |
| 2026-09-25 12:00 |
10:56:07.68 |
-40:15:15.9 |
HIP 53506 |
20.37 |
| 2026-09-26 00:00 |
10:56:15.65 |
-40:15:52.3 |
HIP 53506 |
19.32 |
| 2026-09-26 12:00 |
10:56:23.60 |
-40:16:29.2 |
HIP 53506 |
18.34 |
| 2026-09-27 00:00 |
10:56:31.52 |
-40:17:06.6 |
HIP 53506 |
17.46 |
| 2026-09-27 12:00 |
10:56:39.42 |
-40:17:44.4 |
HIP 53506 |
16.68 |
| 2026-09-28 00:00 |
10:56:47.30 |
-40:18:22.7 |
HIP 53506 |
16.02 |
| 2026-09-28 12:00 |
10:56:55.15 |
-40:19:01.5 |
HIP 53506 |
15.49 |
| 2026-09-29 00:00 |
10:57:02.97 |
-40:19:40.8 |
HIP 53506 |
15.12 |
| 2026-09-29 12:00 |
10:57:10.77 |
-40:20:20.5 |
HIP 53506 |
14.90 |
| 2026-09-30 00:00 |
10:57:18.54 |
-40:21:00.7 |
HIP 53506 |
14.85 |
| 2026-09-30 12:00 |
10:57:26.29 |
-40:21:41.3 |
HIP 53506 |
14.97 |
| 2026-10-01 00:00 |
10:57:34.00 |
-40:22:22.4 |
HIP 53506 |
15.25 |
| 2026-10-01 12:00 |
10:57:41.69 |
-40:23:03.9 |
HIP 53506 |
15.69 |
| 2026-10-02 00:00 |
10:57:49.35 |
-40:23:45.9 |
HIP 53506 |
16.26 |
| 2026-10-02 12:00 |
10:57:56.99 |
-40:24:28.3 |
HIP 53506 |
16.96 |
| 2026-10-03 00:00 |
10:58:04.59 |
-40:25:11.2 |
HIP 53506 |
17.78 |
| 2026-10-03 12:00 |
10:58:12.16 |
-40:25:54.5 |
HIP 53506 |
18.68 |
| 2026-10-04 00:00 |
10:58:19.71 |
-40:26:38.3 |
HIP 53506 |
19.67 |
| 2026-10-04 12:00 |
10:58:27.22 |
-40:27:22.5 |
HIP 53506 |
20.73 |
| 2026-10-05 00:00 |
10:58:34.70 |
-40:28:07.1 |
HIP 53506 |
21.85 |
| 2026-10-05 12:00 |
10:58:42.15 |
-40:28:52.1 |
HIP 53506 |
23.01 |
| 2026-10-06 00:00 |
10:58:49.57 |
-40:29:37.6 |
HIP 53793 |
22.84 |
| 2026-10-06 12:00 |
10:58:56.96 |
-40:30:23.4 |
HIP 53840 |
21.75 |
| 2026-10-07 00:00 |
10:59:04.31 |
-40:31:09.7 |
HIP 53840 |
20.38 |
| 2026-10-07 12:00 |
10:59:11.63 |
-40:31:56.5 |
HIP 53840 |
19.06 |
| 2026-10-08 00:00 |
10:59:18.91 |
-40:32:43.6 |
HIP 53840 |
17.79 |
| 2026-10-08 12:00 |
10:59:26.16 |
-40:33:31.1 |
HIP 53840 |
16.58 |
| 2026-10-09 00:00 |
10:59:33.38 |
-40:34:19.0 |
HIP 53840 |
15.46 |
| 2026-10-09 12:00 |
10:59:40.56 |
-40:35:07.3 |
HIP 53840 |
14.43 |
| 2026-10-10 00:00 |
10:59:47.70 |
-40:35:56.1 |
HIP 53840 |
13.51 |
| 2026-10-10 12:00 |
10:59:54.81 |
-40:36:45.2 |
HIP 53840 |
12.74 |
| 2026-10-11 00:00 |
11:00:01.88 |
-40:37:34.6 |
HIP 53840 |
12.14 |