| 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) |
| 2026-07-29 00:00 |
09:46:48.89 |
-67:02:30.1 |
HIP 48066 |
12.44 |
| 2026-07-29 12:00 |
09:47:02.58 |
-67:02:16.1 |
HIP 48066 |
11.61 |
| 2026-07-30 00:00 |
09:47:16.29 |
-67:02:02.7 |
HIP 48066 |
10.89 |
| 2026-07-30 12:00 |
09:47:30.03 |
-67:01:49.9 |
HIP 48066 |
10.32 |
| 2026-07-31 00:00 |
09:47:43.79 |
-67:01:37.8 |
HIP 48066 |
9.90 |
| 2026-07-31 12:00 |
09:47:57.57 |
-67:01:26.3 |
HIP 48066 |
9.68 |
| 2026-08-01 00:00 |
09:48:11.38 |
-67:01:15.5 |
HIP 48066 |
9.66 |
| 2026-08-01 12:00 |
09:48:25.21 |
-67:01:05.4 |
HIP 48066 |
9.83 |
| 2026-08-02 00:00 |
09:48:39.07 |
-67:00:55.9 |
HIP 48066 |
10.20 |
| 2026-08-02 12:00 |
09:48:52.95 |
-67:00:47.1 |
HIP 48066 |
10.75 |
| 2026-08-03 00:00 |
09:49:06.84 |
-67:00:38.9 |
HIP 48279 |
11.30 |
| 2026-08-03 12:00 |
09:49:20.76 |
-67:00:31.3 |
HIP 48279 |
10.45 |
| 2026-08-04 00:00 |
09:49:34.70 |
-67:00:24.4 |
HIP 48279 |
9.70 |
| 2026-08-04 12:00 |
09:49:48.65 |
-67:00:18.2 |
HIP 48279 |
9.09 |
| 2026-08-05 00:00 |
09:50:02.63 |
-67:00:12.6 |
HIP 48279 |
8.64 |
| 2026-08-05 12:00 |
09:50:16.62 |
-67:00:07.7 |
HIP 48279 |
8.38 |
| 2026-08-06 00:00 |
09:50:30.64 |
-67:00:03.4 |
HIP 48279 |
8.32 |
| 2026-08-06 12:00 |
09:50:44.66 |
-66:59:59.8 |
HIP 48279 |
8.48 |
| 2026-08-07 00:00 |
09:50:58.71 |
-66:59:56.9 |
HIP 48279 |
8.83 |
| 2026-08-07 12:00 |
09:51:12.77 |
-66:59:54.6 |
HIP 48279 |
9.37 |
| 2026-08-08 00:00 |
09:51:26.84 |
-66:59:53.0 |
HIP 48279 |
10.06 |
| 2026-08-08 12:00 |
09:51:40.93 |
-66:59:52.0 |
HIP 48279 |
10.87 |
| 2026-08-09 00:00 |
09:51:55.03 |
-66:59:51.7 |
HIP 48279 |
11.77 |
| 2026-08-09 12:00 |
09:52:09.15 |
-66:59:52.0 |
HIP 48389 |
12.34 |
| 2026-08-10 00:00 |
09:52:23.28 |
-66:59:53.0 |
HIP 48389 |
12.62 |
| 2026-08-10 12:00 |
09:52:37.41 |
-66:59:54.7 |
HIP 48389 |
13.05 |
| 2026-08-11 00:00 |
09:52:51.56 |
-66:59:57.0 |
HIP 48389 |
13.61 |
| 2026-08-11 12:00 |
09:53:05.72 |
-67:00:00.0 |
HIP 48389 |
14.30 |
| 2026-08-12 00:00 |
09:53:19.89 |
-67:00:03.7 |
HIP 48389 |
15.10 |
| 2026-08-12 12:00 |
09:53:34.07 |
-67:00:08.0 |
HIP 48389 |
15.99 |
| 2026-08-13 00:00 |
09:53:48.25 |
-67:00:13.0 |
HIP 48389 |
16.95 |
| 2026-08-13 12:00 |
09:54:02.45 |
-67:00:18.6 |
HIP 48389 |
17.98 |
| 2026-08-14 00:00 |
09:54:16.64 |
-67:00:24.9 |
HIP 48528 |
18.97 |
| 2026-08-14 12:00 |
09:54:30.85 |
-67:00:31.9 |
HIP 48528 |
19.09 |
| 2026-08-15 00:00 |
09:54:45.05 |
-67:00:39.5 |
HIP 48528 |
19.29 |
| 2026-08-15 12:00 |
09:54:59.27 |
-67:00:47.8 |
HIP 48886 |
19.13 |
| 2026-08-16 00:00 |
09:55:13.48 |
-67:00:56.7 |
HIP 48886 |
17.74 |
| 2026-08-16 12:00 |
09:55:27.70 |
-67:01:06.3 |
HIP 48886 |
16.36 |
| 2026-08-17 00:00 |
09:55:41.92 |
-67:01:16.6 |
HIP 48886 |
14.97 |
| 2026-08-17 12:00 |
09:55:56.14 |
-67:01:27.5 |
HIP 48886 |
13.59 |
| 2026-08-18 00:00 |
09:56:10.36 |
-67:01:39.1 |
HIP 48886 |
12.22 |
| 2026-08-18 12:00 |
09:56:24.58 |
-67:01:51.3 |
HIP 48886 |
10.85 |
| 2026-08-19 00:00 |
09:56:38.81 |
-67:02:04.1 |
HIP 48886 |
9.50 |