| 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) |
| 2026-03-26 00:00 |
23:33:38.08 |
+47:11:41.6 |
HIP 116222 |
13.32 |
| 2026-03-26 12:00 |
23:33:47.63 |
+47:12:21.7 |
HIP 116222 |
14.82 |
| 2026-03-27 00:00 |
23:33:57.17 |
+47:13:02.2 |
HIP 116222 |
16.38 |
| 2026-03-27 12:00 |
23:34:06.68 |
+47:13:43.3 |
HIP 116222 |
17.98 |
| 2026-03-28 00:00 |
23:34:16.18 |
+47:14:25.0 |
HIP 116457 |
19.58 |
| 2026-03-28 12:00 |
23:34:25.66 |
+47:15:07.1 |
HIP 116457 |
17.87 |
| 2026-03-29 00:00 |
23:34:35.12 |
+47:15:49.7 |
HIP 116457 |
16.16 |
| 2026-03-29 12:00 |
23:34:44.56 |
+47:16:32.9 |
HIP 116457 |
14.46 |
| 2026-03-30 00:00 |
23:34:53.97 |
+47:17:16.5 |
HIP 116457 |
12.76 |
| 2026-03-30 12:00 |
23:35:03.37 |
+47:18:00.7 |
HIP 116457 |
11.09 |
| 2026-03-31 00:00 |
23:35:12.74 |
+47:18:45.4 |
HIP 116457 |
9.44 |
| 2026-03-31 12:00 |
23:35:22.10 |
+47:19:30.5 |
HIP 116457 |
7.84 |
| 2026-04-01 00:00 |
23:35:31.43 |
+47:20:16.2 |
HIP 116457 |
6.30 |
| 2026-04-01 12:00 |
23:35:40.74 |
+47:21:02.3 |
HIP 116457 |
4.92 |
| 2026-04-02 00:00 |
23:35:50.02 |
+47:21:48.9 |
HIP 116457 |
3.83 |
| 2026-04-02 12:00 |
23:35:59.28 |
+47:22:36.0 |
HIP 116457 |
3.36 |
| 2026-04-03 00:00 |
23:36:08.52 |
+47:23:23.6 |
HIP 116457 |
3.74 |
| 2026-04-03 12:00 |
23:36:17.73 |
+47:24:11.7 |
HIP 116457 |
4.77 |
| 2026-04-04 00:00 |
23:36:26.92 |
+47:25:00.2 |
HIP 116457 |
6.13 |
| 2026-04-04 12:00 |
23:36:36.08 |
+47:25:49.3 |
HIP 116457 |
7.64 |
| 2026-04-05 00:00 |
23:36:45.22 |
+47:26:38.7 |
HIP 116457 |
9.24 |
| 2026-04-05 12:00 |
23:36:54.33 |
+47:27:28.7 |
HIP 116457 |
10.88 |
| 2026-04-06 00:00 |
23:37:03.41 |
+47:28:19.1 |
HIP 116457 |
12.55 |
| 2026-04-06 12:00 |
23:37:12.47 |
+47:29:10.0 |
HIP 116457 |
14.23 |
| 2026-04-07 00:00 |
23:37:21.49 |
+47:30:01.3 |
HIP 116457 |
15.93 |
| 2026-04-07 12:00 |
23:37:30.49 |
+47:30:53.1 |
HIP 116605 |
16.03 |
| 2026-04-08 00:00 |
23:37:39.47 |
+47:31:45.3 |
HIP 116605 |
14.90 |
| 2026-04-08 12:00 |
23:37:48.41 |
+47:32:38.0 |
HIP 116605 |
13.89 |
| 2026-04-09 00:00 |
23:37:57.32 |
+47:33:31.1 |
HIP 116605 |
13.03 |
| 2026-04-09 12:00 |
23:38:06.21 |
+47:34:24.7 |
HIP 116605 |
12.35 |
| 2026-04-10 00:00 |
23:38:15.06 |
+47:35:18.7 |
HIP 116605 |
11.88 |
| 2026-04-10 12:00 |
23:38:23.88 |
+47:36:13.2 |
HIP 116605 |
11.64 |
| 2026-04-11 00:00 |
23:38:32.67 |
+47:37:08.0 |
HIP 116605 |
11.65 |
| 2026-04-11 12:00 |
23:38:41.43 |
+47:38:03.3 |
HIP 116605 |
11.91 |
| 2026-04-12 00:00 |
23:38:50.16 |
+47:38:59.1 |
HIP 116605 |
12.40 |
| 2026-04-12 12:00 |
23:38:58.85 |
+47:39:55.2 |
HIP 116605 |
13.10 |
| 2026-04-13 00:00 |
23:39:07.51 |
+47:40:51.8 |
HIP 116605 |
13.97 |
| 2026-04-13 12:00 |
23:39:16.14 |
+47:41:48.8 |
HIP 116605 |
14.98 |
| 2026-04-14 00:00 |
23:39:24.73 |
+47:42:46.2 |
HIP 116605 |
16.10 |
| 2026-04-14 12:00 |
23:39:33.29 |
+47:43:44.0 |
HIP 116605 |
17.32 |
| 2026-04-15 00:00 |
23:39:41.82 |
+47:44:42.2 |
HIP 116605 |
18.62 |
| 2026-04-15 12:00 |
23:39:50.30 |
+47:45:40.8 |
HIP 116883 |
19.46 |
| 2026-04-16 00:00 |
23:39:58.75 |
+47:46:39.8 |
HIP 116883 |
18.81 |