| 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 · 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) |
| 2026-05-12 00:00 |
09:24:17.06 |
-69:30:13.8 |
HIP 46233 |
10.42 |
| 2026-05-12 12:00 |
09:24:17.73 |
-69:28:49.2 |
HIP 46233 |
11.51 |
| 2026-05-13 00:00 |
09:24:18.53 |
-69:27:24.7 |
HIP 46233 |
12.65 |
| 2026-05-13 12:00 |
09:24:19.48 |
-69:26:00.2 |
HIP 46233 |
13.83 |
| 2026-05-14 00:00 |
09:24:20.56 |
-69:24:35.9 |
HIP 46287 |
13.64 |
| 2026-05-14 12:00 |
09:24:21.79 |
-69:23:11.7 |
HIP 46287 |
12.74 |
| 2026-05-15 00:00 |
09:24:23.16 |
-69:21:47.6 |
HIP 46287 |
11.92 |
| 2026-05-15 12:00 |
09:24:24.66 |
-69:20:23.6 |
HIP 45993 |
11.12 |
| 2026-05-16 00:00 |
09:24:26.31 |
-69:18:59.8 |
HIP 45993 |
10.40 |
| 2026-05-16 12:00 |
09:24:28.09 |
-69:17:36.0 |
HIP 45993 |
9.83 |
| 2026-05-17 00:00 |
09:24:30.00 |
-69:16:12.5 |
HIP 45993 |
9.46 |
| 2026-05-17 12:00 |
09:24:32.06 |
-69:14:49.1 |
HIP 45993 |
9.30 |
| 2026-05-18 00:00 |
09:24:34.24 |
-69:13:25.8 |
HIP 45993 |
9.36 |
| 2026-05-18 12:00 |
09:24:36.57 |
-69:12:02.7 |
HIP 45993 |
9.64 |
| 2026-05-19 00:00 |
09:24:39.02 |
-69:10:39.8 |
HIP 45993 |
10.12 |
| 2026-05-19 12:00 |
09:24:41.61 |
-69:09:17.1 |
HIP 45993 |
10.77 |
| 2026-05-20 00:00 |
09:24:44.34 |
-69:07:54.5 |
HIP 45993 |
11.56 |
| 2026-05-20 12:00 |
09:24:47.19 |
-69:06:32.2 |
HIP 45993 |
12.47 |
| 2026-05-21 00:00 |
09:24:50.18 |
-69:05:10.0 |
HIP 45993 |
13.47 |
| 2026-05-21 12:00 |
09:24:53.29 |
-69:03:48.1 |
HIP 45993 |
14.54 |
| 2026-05-22 00:00 |
09:24:56.53 |
-69:02:26.4 |
HIP 45993 |
15.67 |
| 2026-05-22 12:00 |
09:24:59.91 |
-69:01:04.9 |
HIP 46287 |
16.78 |
| 2026-05-23 00:00 |
09:25:03.40 |
-68:59:43.6 |
HIP 46287 |
17.88 |
| 2026-05-23 12:00 |
09:25:07.03 |
-68:58:22.5 |
HIP 46287 |
19.02 |
| 2026-05-24 00:00 |
09:25:10.78 |
-68:57:01.7 |
HIP 46287 |
20.18 |
| 2026-05-24 12:00 |
09:25:14.66 |
-68:55:41.1 |
HIP 46287 |
21.36 |
| 2026-05-25 00:00 |
09:25:18.66 |
-68:54:20.8 |
HIP 46287 |
22.55 |
| 2026-05-25 12:00 |
09:25:22.78 |
-68:53:00.7 |
HIP 46287 |
23.76 |
| 2026-05-26 00:00 |
09:25:27.03 |
-68:51:40.9 |
HIP 46287 |
24.98 |
| 2026-05-26 12:00 |
09:25:31.40 |
-68:50:21.3 |
HIP 46287 |
26.22 |
| 2026-05-27 00:00 |
09:25:35.88 |
-68:49:02.0 |
HIP 46205 |
27.36 |
| 2026-05-27 12:00 |
09:25:40.49 |
-68:47:43.0 |
HIP 46205 |
26.08 |
| 2026-05-28 00:00 |
09:25:45.22 |
-68:46:24.3 |
HIP 46205 |
24.82 |
| 2026-05-28 12:00 |
09:25:50.07 |
-68:45:05.9 |
HIP 46205 |
23.58 |
| 2026-05-29 00:00 |
09:25:55.03 |
-68:43:47.7 |
HIP 46205 |
22.35 |
| 2026-05-29 12:00 |
09:26:00.11 |
-68:42:29.8 |
HIP 46205 |
21.16 |
| 2026-05-30 00:00 |
09:26:05.31 |
-68:41:12.3 |
HIP 46205 |
20.00 |
| 2026-05-30 12:00 |
09:26:10.62 |
-68:39:55.0 |
HIP 46205 |
18.87 |
| 2026-05-31 00:00 |
09:26:16.05 |
-68:38:38.1 |
HIP 46205 |
17.78 |
| 2026-05-31 12:00 |
09:26:21.59 |
-68:37:21.4 |
HIP 46205 |
16.75 |
| 2026-06-01 00:00 |
09:26:27.24 |
-68:36:05.1 |
HIP 46205 |
15.78 |
| 2026-06-01 12:00 |
09:26:33.01 |
-68:34:49.1 |
HIP 46205 |
14.89 |
| 2026-06-02 00:00 |
09:26:38.89 |
-68:33:33.4 |
HIP 46205 |
14.08 |