| 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) |
| 2026-05-12 00:00 |
10:30:50.07 |
-43:40:25.2 |
HIP 51621 |
21.26 |
| 2026-05-12 12:00 |
10:30:48.10 |
-43:38:34.1 |
HIP 51621 |
21.47 |
| 2026-05-13 00:00 |
10:30:46.21 |
-43:36:43.1 |
HIP 51621 |
21.81 |
| 2026-05-13 12:00 |
10:30:44.41 |
-43:34:52.3 |
HIP 51621 |
22.30 |
| 2026-05-14 00:00 |
10:30:42.69 |
-43:33:01.5 |
HIP 51621 |
22.92 |
| 2026-05-14 12:00 |
10:30:41.05 |
-43:31:10.9 |
HIP 51621 |
23.65 |
| 2026-05-15 00:00 |
10:30:39.49 |
-43:29:20.3 |
HIP 51412 |
22.54 |
| 2026-05-15 12:00 |
10:30:38.02 |
-43:27:30.0 |
HIP 51412 |
20.71 |
| 2026-05-16 00:00 |
10:30:36.63 |
-43:25:39.7 |
HIP 51412 |
18.88 |
| 2026-05-16 12:00 |
10:30:35.32 |
-43:23:49.6 |
HIP 51412 |
17.08 |
| 2026-05-17 00:00 |
10:30:34.10 |
-43:21:59.7 |
HIP 51412 |
15.29 |
| 2026-05-17 12:00 |
10:30:32.96 |
-43:20:10.0 |
HIP 51412 |
13.52 |
| 2026-05-18 00:00 |
10:30:31.90 |
-43:18:20.4 |
HIP 51412 |
11.78 |
| 2026-05-18 12:00 |
10:30:30.93 |
-43:16:31.0 |
HIP 51412 |
10.09 |
| 2026-05-19 00:00 |
10:30:30.03 |
-43:14:41.8 |
HIP 51412 |
8.47 |
| 2026-05-19 12:00 |
10:30:29.22 |
-43:12:52.8 |
HIP 51412 |
6.97 |
| 2026-05-20 00:00 |
10:30:28.49 |
-43:11:04.0 |
HIP 51412 |
5.67 |
| 2026-05-20 12:00 |
10:30:27.85 |
-43:09:15.5 |
HIP 51412 |
4.74 |
| 2026-05-21 00:00 |
10:30:27.28 |
-43:07:27.1 |
HIP 51412 |
4.42 |
| 2026-05-21 12:00 |
10:30:26.80 |
-43:05:39.0 |
HIP 51412 |
4.82 |
| 2026-05-22 00:00 |
10:30:26.40 |
-43:03:51.1 |
HIP 51412 |
5.79 |
| 2026-05-22 12:00 |
10:30:26.07 |
-43:02:03.5 |
HIP 51412 |
7.10 |
| 2026-05-23 00:00 |
10:30:25.83 |
-43:00:16.1 |
HIP 51412 |
8.59 |
| 2026-05-23 12:00 |
10:30:25.67 |
-42:58:28.9 |
HIP 51379 |
9.80 |
| 2026-05-24 00:00 |
10:30:25.59 |
-42:56:42.0 |
HIP 51379 |
10.73 |
| 2026-05-24 12:00 |
10:30:25.59 |
-42:54:55.4 |
HIP 51379 |
11.87 |
| 2026-05-25 00:00 |
10:30:25.67 |
-42:53:09.1 |
HIP 51379 |
13.16 |
| 2026-05-25 12:00 |
10:30:25.83 |
-42:51:23.0 |
HIP 51379 |
14.55 |
| 2026-05-26 00:00 |
10:30:26.07 |
-42:49:37.3 |
HIP 51379 |
16.03 |
| 2026-05-26 12:00 |
10:30:26.39 |
-42:47:51.8 |
HIP 51379 |
17.56 |
| 2026-05-27 00:00 |
10:30:26.79 |
-42:46:06.6 |
HIP 51379 |
19.13 |
| 2026-05-27 12:00 |
10:30:27.26 |
-42:44:21.7 |
HIP 51379 |
20.73 |
| 2026-05-28 00:00 |
10:30:27.81 |
-42:42:37.2 |
HIP 51379 |
22.36 |
| 2026-05-28 12:00 |
10:30:28.44 |
-42:40:52.9 |
HIP 51397 |
21.22 |
| 2026-05-29 00:00 |
10:30:29.15 |
-42:39:09.0 |
HIP 51397 |
19.63 |
| 2026-05-29 12:00 |
10:30:29.94 |
-42:37:25.4 |
HIP 51397 |
18.09 |
| 2026-05-30 00:00 |
10:30:30.80 |
-42:35:42.1 |
HIP 51397 |
16.59 |
| 2026-05-30 12:00 |
10:30:31.74 |
-42:33:59.2 |
HIP 51397 |
15.16 |
| 2026-05-31 00:00 |
10:30:32.76 |
-42:32:16.6 |
HIP 51397 |
13.80 |
| 2026-05-31 12:00 |
10:30:33.85 |
-42:30:34.4 |
HIP 51397 |
12.55 |
| 2026-06-01 00:00 |
10:30:35.02 |
-42:28:52.5 |
HIP 51397 |
11.43 |
| 2026-06-01 12:00 |
10:30:36.27 |
-42:27:11.0 |
HIP 51397 |
10.49 |
| 2026-06-02 00:00 |
10:30:37.59 |
-42:25:29.8 |
HIP 51397 |
9.78 |