| Parameter |
Value |
| Designation |
C/2018 R3 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-06-07T04:45:17.421120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:46Z |
| Obs used |
272 |
| NEO |
- |
| M1 |
11.300 |
| K1 |
11.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2018-09-07T03:53:59.136000Z |
| Discovery magnitude (MPC) |
19.20 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-02-24.0000000 |
| e |
0.99934491 |
| q (au) |
1.290602 |
| a (au) |
1970.100092 |
| i (deg) |
69.715410 |
| Ω (om, deg) |
324.626026 |
| ω (w, deg) |
112.875459 |
| M (ma, deg) |
359.998837 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.265 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.265 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.875 |
| k |
0.998 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2018-08-08 |
2019-06-07 |
-0.2234 |
+0.114 |
| 2019-06-07 |
2020-03-03 |
+8.0397 |
-3.207 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
10:11:18.28 |
-67:37:32.2 |
HIP 49835 |
13.73 |
| 2026-09-20 12:00 |
10:11:31.07 |
-67:38:24.8 |
HIP 49835 |
13.39 |
| 2026-09-21 00:00 |
10:11:43.81 |
-67:39:17.9 |
HIP 49835 |
13.19 |
| 2026-09-21 12:00 |
10:11:56.50 |
-67:40:11.5 |
HIP 49835 |
13.15 |
| 2026-09-22 00:00 |
10:12:09.15 |
-67:41:05.7 |
HIP 49835 |
13.28 |
| 2026-09-22 12:00 |
10:12:21.76 |
-67:42:00.5 |
HIP 49892 |
13.25 |
| 2026-09-23 00:00 |
10:12:34.31 |
-67:42:55.7 |
HIP 49892 |
13.11 |
| 2026-09-23 12:00 |
10:12:46.82 |
-67:43:51.5 |
HIP 49892 |
13.14 |
| 2026-09-24 00:00 |
10:12:59.28 |
-67:44:47.9 |
HIP 49892 |
13.32 |
| 2026-09-24 12:00 |
10:13:11.69 |
-67:45:44.7 |
HIP 49892 |
13.66 |
| 2026-09-25 00:00 |
10:13:24.05 |
-67:46:42.1 |
HIP 49892 |
14.15 |
| 2026-09-25 12:00 |
10:13:36.36 |
-67:47:40.0 |
HIP 49892 |
14.76 |
| 2026-09-26 00:00 |
10:13:48.62 |
-67:48:38.5 |
HIP 50108 |
14.95 |
| 2026-09-26 12:00 |
10:14:00.83 |
-67:49:37.4 |
HIP 50108 |
14.01 |
| 2026-09-27 00:00 |
10:14:12.98 |
-67:50:36.9 |
HIP 50108 |
13.17 |
| 2026-09-27 12:00 |
10:14:25.09 |
-67:51:36.8 |
HIP 50108 |
12.44 |
| 2026-09-28 00:00 |
10:14:37.13 |
-67:52:37.3 |
HIP 50108 |
11.85 |
| 2026-09-28 12:00 |
10:14:49.13 |
-67:53:38.3 |
HIP 50108 |
11.43 |
| 2026-09-29 00:00 |
10:15:01.07 |
-67:54:39.8 |
HIP 50108 |
11.18 |
| 2026-09-29 12:00 |
10:15:12.95 |
-67:55:41.8 |
HIP 50108 |
11.13 |
| 2026-09-30 00:00 |
10:15:24.78 |
-67:56:44.3 |
HIP 50108 |
11.27 |
| 2026-09-30 12:00 |
10:15:36.55 |
-67:57:47.3 |
HIP 50108 |
11.60 |
| 2026-10-01 00:00 |
10:15:48.26 |
-67:58:50.7 |
HIP 50108 |
12.10 |
| 2026-10-01 12:00 |
10:15:59.92 |
-67:59:54.7 |
HIP 50108 |
12.76 |
| 2026-10-02 00:00 |
10:16:11.51 |
-68:00:59.2 |
HIP 50164 |
13.45 |
| 2026-10-02 12:00 |
10:16:23.05 |
-68:02:04.1 |
HIP 50164 |
13.65 |
| 2026-10-03 00:00 |
10:16:34.52 |
-68:03:09.6 |
HIP 50164 |
14.00 |
| 2026-10-03 12:00 |
10:16:45.94 |
-68:04:15.5 |
HIP 50164 |
14.50 |
| 2026-10-04 00:00 |
10:16:57.29 |
-68:05:21.9 |
HIP 50164 |
15.13 |
| 2026-10-04 12:00 |
10:17:08.58 |
-68:06:28.7 |
HIP 50164 |
15.86 |
| 2026-10-05 00:00 |
10:17:19.80 |
-68:07:36.1 |
HIP 50164 |
16.70 |
| 2026-10-05 12:00 |
10:17:30.96 |
-68:08:43.9 |
HIP 50164 |
17.63 |
| 2026-10-06 00:00 |
10:17:42.06 |
-68:09:52.2 |
HIP 50659 |
18.08 |
| 2026-10-06 12:00 |
10:17:53.08 |
-68:11:00.9 |
HIP 50659 |
17.54 |
| 2026-10-07 00:00 |
10:18:04.05 |
-68:12:10.1 |
HIP 50659 |
17.13 |
| 2026-10-07 12:00 |
10:18:14.94 |
-68:13:19.8 |
HIP 50659 |
16.86 |
| 2026-10-08 00:00 |
10:18:25.77 |
-68:14:29.9 |
HIP 50659 |
16.74 |
| 2026-10-08 12:00 |
10:18:36.52 |
-68:15:40.4 |
HIP 50659 |
16.77 |
| 2026-10-09 00:00 |
10:18:47.21 |
-68:16:51.4 |
HIP 50659 |
16.96 |
| 2026-10-09 12:00 |
10:18:57.82 |
-68:18:02.9 |
HIP 50659 |
17.29 |
| 2026-10-10 00:00 |
10:19:08.36 |
-68:19:14.8 |
HIP 50659 |
17.77 |
| 2026-10-10 12:00 |
10:19:18.83 |
-68:20:27.1 |
HIP 50659 |
18.37 |
| 2026-10-11 00:00 |
10:19:29.23 |
-68:21:39.8 |
HIP 50659 |
19.09 |