| Parameter |
Value |
| Designation |
C/2019 U6 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-06-18T19:43:24.988800Z |
| Orbit solution date (soln_date, UTC) |
2022-04-16T22:12:22Z |
| Obs used |
1144 |
| NEO |
- |
| M1 |
13.200 |
| K1 |
7.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-10-31T10:24:29.952000Z |
| Discovery magnitude (MPC) |
20.50 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-04-28.0000000 |
| e |
0.99790319 |
| q (au) |
0.914264 |
| a (au) |
436.025928 |
| i (deg) |
61.001339 |
| Ω (om, deg) |
235.705755 |
| ω (w, deg) |
329.659058 |
| M (ma, deg) |
359.994390 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.998 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.998 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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 |
| 2018-11-06 |
2020-01-26 |
-9.9490 |
+4.967 |
| 2020-01-26 |
2020-04-22 |
+11.1473 |
-3.130 |
| 2020-04-22 |
2020-06-18 |
-1.0370 |
-2.413 |
| 2020-06-18 |
2020-07-26 |
+16.3476 |
-0.540 |
| 2020-07-26 |
2020-11-28 |
-5.2648 |
+1.320 |
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 |
23:46:17.47 |
+48:45:11.7 |
HIP 117286 |
6.76 |
| 2026-05-12 12:00 |
23:46:23.39 |
+48:46:25.9 |
HIP 117286 |
5.39 |
| 2026-05-13 00:00 |
23:46:29.26 |
+48:47:40.2 |
HIP 117286 |
4.18 |
| 2026-05-13 12:00 |
23:46:35.07 |
+48:48:54.7 |
HIP 117286 |
3.30 |
| 2026-05-14 00:00 |
23:46:40.82 |
+48:50:09.4 |
HIP 117286 |
3.05 |
| 2026-05-14 12:00 |
23:46:46.51 |
+48:51:24.3 |
HIP 117286 |
3.56 |
| 2026-05-15 00:00 |
23:46:52.14 |
+48:52:39.3 |
HIP 117286 |
4.57 |
| 2026-05-15 12:00 |
23:46:57.70 |
+48:53:54.5 |
HIP 117286 |
5.83 |
| 2026-05-16 00:00 |
23:47:03.21 |
+48:55:09.8 |
HIP 117286 |
7.21 |
| 2026-05-16 12:00 |
23:47:08.66 |
+48:56:25.3 |
HIP 117286 |
8.64 |
| 2026-05-17 00:00 |
23:47:14.04 |
+48:57:40.9 |
HIP 117383 |
8.61 |
| 2026-05-17 12:00 |
23:47:19.37 |
+48:58:56.7 |
HIP 117383 |
7.36 |
| 2026-05-18 00:00 |
23:47:24.63 |
+49:00:12.5 |
HIP 117383 |
6.27 |
| 2026-05-18 12:00 |
23:47:29.82 |
+49:01:28.5 |
HIP 117383 |
5.40 |
| 2026-05-19 00:00 |
23:47:34.96 |
+49:02:44.7 |
HIP 117383 |
4.87 |
| 2026-05-19 12:00 |
23:47:40.03 |
+49:04:00.9 |
HIP 117383 |
4.80 |
| 2026-05-20 00:00 |
23:47:45.04 |
+49:05:17.2 |
HIP 117383 |
5.21 |
| 2026-05-20 12:00 |
23:47:49.98 |
+49:06:33.7 |
HIP 117383 |
5.98 |
| 2026-05-21 00:00 |
23:47:54.86 |
+49:07:50.2 |
HIP 117383 |
7.01 |
| 2026-05-21 12:00 |
23:47:59.67 |
+49:09:06.9 |
HIP 117383 |
8.18 |
| 2026-05-22 00:00 |
23:48:04.42 |
+49:10:23.6 |
HIP 117334 |
9.15 |
| 2026-05-22 12:00 |
23:48:09.10 |
+49:11:40.4 |
HIP 117334 |
8.72 |
| 2026-05-23 00:00 |
23:48:13.72 |
+49:12:57.3 |
HIP 117334 |
8.53 |
| 2026-05-23 12:00 |
23:48:18.27 |
+49:14:14.3 |
HIP 117334 |
8.58 |
| 2026-05-24 00:00 |
23:48:22.76 |
+49:15:31.4 |
HIP 117334 |
8.87 |
| 2026-05-24 12:00 |
23:48:27.17 |
+49:16:48.5 |
HIP 117334 |
9.38 |
| 2026-05-25 00:00 |
23:48:31.53 |
+49:18:05.6 |
HIP 117334 |
10.06 |
| 2026-05-25 12:00 |
23:48:35.81 |
+49:19:22.9 |
HIP 117443 |
10.56 |
| 2026-05-26 00:00 |
23:48:40.03 |
+49:20:40.2 |
HIP 117443 |
9.17 |
| 2026-05-26 12:00 |
23:48:44.18 |
+49:21:57.5 |
HIP 117443 |
7.82 |
| 2026-05-27 00:00 |
23:48:48.26 |
+49:23:14.9 |
HIP 117443 |
6.51 |
| 2026-05-27 12:00 |
23:48:52.27 |
+49:24:32.3 |
HIP 117443 |
5.27 |
| 2026-05-28 00:00 |
23:48:56.22 |
+49:25:49.8 |
HIP 117443 |
4.16 |
| 2026-05-28 12:00 |
23:49:00.09 |
+49:27:07.2 |
HIP 117443 |
3.32 |
| 2026-05-29 00:00 |
23:49:03.90 |
+49:28:24.7 |
HIP 117443 |
2.95 |
| 2026-05-29 12:00 |
23:49:07.64 |
+49:29:42.3 |
HIP 117443 |
3.23 |
| 2026-05-30 00:00 |
23:49:11.31 |
+49:30:59.8 |
HIP 117443 |
4.02 |
| 2026-05-30 12:00 |
23:49:14.91 |
+49:32:17.4 |
HIP 117443 |
5.09 |
| 2026-05-31 00:00 |
23:49:18.44 |
+49:33:35.0 |
HIP 117443 |
6.28 |
| 2026-05-31 12:00 |
23:49:21.90 |
+49:34:52.6 |
HIP 117443 |
7.55 |
| 2026-06-01 00:00 |
23:49:25.29 |
+49:36:10.1 |
HIP 117443 |
8.84 |
| 2026-06-01 12:00 |
23:49:28.60 |
+49:37:27.7 |
HIP 117443 |
10.16 |
| 2026-06-02 00:00 |
23:49:31.85 |
+49:38:45.3 |
HIP 117443 |
11.49 |