| Parameter |
Value |
| Designation |
C/2016 X1 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-04-29T21:10:40.776960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:28Z |
| Obs used |
289 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
9.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-09-28.0000000 |
| e |
0.99625285 |
| q (au) |
7.564181 |
| a (au) |
2018.648757 |
| i (deg) |
26.455050 |
| Ω (om, deg) |
256.425245 |
| ω (w, deg) |
224.569464 |
| M (ma, deg) |
359.997676 |
Magnitude
Scatter + Global Linear
$$
M_a = (0.331 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
0.331 |
| n |
6.000 |
| gf |
0.995 |
| gb |
-0.734 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
14:03:45.11 |
-31:52:49.9 |
HIP 68641 |
14.96 |
| 2026-03-26 12:00 |
14:03:39.75 |
-31:52:34.9 |
HIP 68641 |
14.08 |
| 2026-03-27 00:00 |
14:03:34.35 |
-31:52:19.5 |
HIP 68641 |
13.24 |
| 2026-03-27 12:00 |
14:03:28.92 |
-31:52:03.6 |
HIP 68641 |
12.44 |
| 2026-03-28 00:00 |
14:03:23.46 |
-31:51:47.2 |
HIP 68641 |
11.69 |
| 2026-03-28 12:00 |
14:03:17.96 |
-31:51:30.4 |
HIP 68641 |
11.01 |
| 2026-03-29 00:00 |
14:03:12.43 |
-31:51:13.2 |
HIP 68641 |
10.42 |
| 2026-03-29 12:00 |
14:03:06.87 |
-31:50:55.4 |
HIP 68641 |
9.93 |
| 2026-03-30 00:00 |
14:03:01.28 |
-31:50:37.3 |
HIP 68641 |
9.57 |
| 2026-03-30 12:00 |
14:02:55.66 |
-31:50:18.6 |
HIP 68641 |
9.35 |
| 2026-03-31 00:00 |
14:02:50.00 |
-31:49:59.6 |
HIP 68641 |
9.28 |
| 2026-03-31 12:00 |
14:02:44.32 |
-31:49:40.1 |
HIP 68641 |
9.37 |
| 2026-04-01 00:00 |
14:02:38.61 |
-31:49:20.1 |
HIP 68641 |
9.63 |
| 2026-04-01 12:00 |
14:02:32.87 |
-31:48:59.7 |
HIP 68641 |
10.03 |
| 2026-04-02 00:00 |
14:02:27.11 |
-31:48:38.8 |
HIP 68641 |
10.57 |
| 2026-04-02 12:00 |
14:02:21.32 |
-31:48:17.5 |
HIP 68641 |
11.23 |
| 2026-04-03 00:00 |
14:02:15.50 |
-31:47:55.8 |
HIP 68641 |
11.99 |
| 2026-04-03 12:00 |
14:02:09.66 |
-31:47:33.6 |
HIP 68641 |
12.84 |
| 2026-04-04 00:00 |
14:02:03.79 |
-31:47:11.0 |
HIP 68507 |
12.81 |
| 2026-04-04 12:00 |
14:01:57.90 |
-31:46:48.0 |
HIP 68507 |
11.75 |
| 2026-04-05 00:00 |
14:01:51.98 |
-31:46:24.5 |
HIP 68507 |
10.73 |
| 2026-04-05 12:00 |
14:01:46.05 |
-31:46:00.6 |
HIP 68507 |
9.77 |
| 2026-04-06 00:00 |
14:01:40.09 |
-31:45:36.3 |
HIP 68507 |
8.90 |
| 2026-04-06 12:00 |
14:01:34.11 |
-31:45:11.5 |
HIP 68507 |
8.15 |
| 2026-04-07 00:00 |
14:01:28.10 |
-31:44:46.3 |
HIP 68462 |
7.19 |
| 2026-04-07 12:00 |
14:01:22.08 |
-31:44:20.7 |
HIP 68462 |
6.29 |
| 2026-04-08 00:00 |
14:01:16.04 |
-31:43:54.6 |
HIP 68462 |
5.57 |
| 2026-04-08 12:00 |
14:01:09.98 |
-31:43:28.2 |
HIP 68462 |
5.12 |
| 2026-04-09 00:00 |
14:01:03.91 |
-31:43:01.3 |
HIP 68462 |
5.01 |
| 2026-04-09 12:00 |
14:00:57.81 |
-31:42:34.0 |
HIP 68462 |
5.28 |
| 2026-04-10 00:00 |
14:00:51.70 |
-31:42:06.2 |
HIP 68462 |
5.87 |
| 2026-04-10 12:00 |
14:00:45.58 |
-31:41:38.1 |
HIP 68462 |
6.71 |
| 2026-04-11 00:00 |
14:00:39.43 |
-31:41:09.6 |
HIP 68462 |
7.71 |
| 2026-04-11 12:00 |
14:00:33.28 |
-31:40:40.6 |
HIP 68462 |
8.83 |
| 2026-04-12 00:00 |
14:00:27.11 |
-31:40:11.2 |
HIP 68462 |
10.02 |
| 2026-04-12 12:00 |
14:00:20.93 |
-31:39:41.5 |
HIP 68462 |
11.27 |
| 2026-04-13 00:00 |
14:00:14.73 |
-31:39:11.3 |
HIP 68343 |
12.34 |
| 2026-04-13 12:00 |
14:00:08.53 |
-31:38:40.7 |
HIP 68343 |
11.43 |
| 2026-04-14 00:00 |
14:00:02.31 |
-31:38:09.8 |
HIP 68343 |
10.63 |
| 2026-04-14 12:00 |
13:59:56.08 |
-31:37:38.4 |
HIP 68343 |
9.97 |
| 2026-04-15 00:00 |
13:59:49.85 |
-31:37:06.7 |
HIP 68343 |
9.49 |
| 2026-04-15 12:00 |
13:59:43.60 |
-31:36:34.5 |
HIP 68343 |
9.21 |
| 2026-04-16 00:00 |
13:59:37.35 |
-31:36:02.0 |
HIP 68343 |
9.15 |