C/2018 B1 (Lemmon)
| Parameter |
Value |
| Designation |
C/2018 B1 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-03-30T10:39:55.339200Z |
| Orbit solution date (soln_date, UTC) |
2022-07-19T01:12:15Z |
| Obs used |
316 |
| NEO |
- |
| M1 |
12.300 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-10-22.0000000 |
| e |
1.00296934 |
| q (au) |
5.116718 |
| a (au) |
-1723.183540 |
| i (deg) |
162.423569 |
| Ω (om, deg) |
133.168875 |
| ω (w, deg) |
68.349093 |
| M (ma, deg) |
0.002832 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.479 + 2.127\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.479 |
| n |
2.127 |
| gf |
0.999 |
| gb |
-0.810 |
| k |
0.800 |
| 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 |
| 2017-01-16 |
2018-03-03 |
+44.9933 |
-31.597 |
| 2018-08-17 |
2019-10-31 |
+3.0484 |
-2.392 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
20:46:49.65 |
-19:21:00.2 |
HIP 102528 |
5.91 |
| 2026-02-03 12:00 |
20:46:54.99 |
-19:20:44.6 |
HIP 102528 |
6.79 |
| 2026-02-04 00:00 |
20:47:00.33 |
-19:20:29.1 |
HIP 102528 |
7.77 |
| 2026-02-04 12:00 |
20:47:05.67 |
-19:20:13.5 |
HIP 102528 |
8.84 |
| 2026-02-05 00:00 |
20:47:10.99 |
-19:19:58.0 |
HIP 102528 |
9.95 |
| 2026-02-05 12:00 |
20:47:16.31 |
-19:19:42.6 |
HIP 102528 |
11.10 |
| 2026-02-06 00:00 |
20:47:21.63 |
-19:19:27.2 |
HIP 102528 |
12.27 |
| 2026-02-06 12:00 |
20:47:26.93 |
-19:19:11.8 |
HIP 102660 |
11.59 |
| 2026-02-07 00:00 |
20:47:32.23 |
-19:18:56.5 |
HIP 102660 |
10.33 |
| 2026-02-07 12:00 |
20:47:37.52 |
-19:18:41.2 |
HIP 102660 |
9.07 |
| 2026-02-08 00:00 |
20:47:42.79 |
-19:18:25.9 |
HIP 102660 |
7.81 |
| 2026-02-08 12:00 |
20:47:48.06 |
-19:18:10.7 |
HIP 102660 |
6.56 |
| 2026-02-09 00:00 |
20:47:53.32 |
-19:17:55.6 |
HIP 102660 |
5.33 |
| 2026-02-09 12:00 |
20:47:58.57 |
-19:17:40.5 |
HIP 102660 |
4.11 |
| 2026-02-10 00:00 |
20:48:03.81 |
-19:17:25.4 |
HIP 102660 |
2.95 |
| 2026-02-10 12:00 |
20:48:09.04 |
-19:17:10.4 |
HIP 102660 |
1.90 |
| 2026-02-11 00:00 |
20:48:14.25 |
-19:16:55.5 |
HIP 102660 |
1.32 |
| 2026-02-11 12:00 |
20:48:19.46 |
-19:16:40.6 |
HIP 102660 |
1.73 |
| 2026-02-12 00:00 |
20:48:24.65 |
-19:16:25.7 |
HIP 102660 |
2.72 |
| 2026-02-12 12:00 |
20:48:29.82 |
-19:16:11.0 |
HIP 102660 |
3.86 |
| 2026-02-13 00:00 |
20:48:34.99 |
-19:15:56.3 |
HIP 102660 |
5.04 |
| 2026-02-13 12:00 |
20:48:40.14 |
-19:15:41.6 |
HIP 102660 |
6.25 |
| 2026-02-14 00:00 |
20:48:45.28 |
-19:15:27.0 |
HIP 102660 |
7.46 |
| 2026-02-14 12:00 |
20:48:50.40 |
-19:15:12.5 |
HIP 102660 |
8.68 |
| 2026-02-15 00:00 |
20:48:55.51 |
-19:14:58.0 |
HIP 102660 |
9.90 |
| 2026-02-15 12:00 |
20:49:00.60 |
-19:14:43.7 |
HIP 102660 |
11.11 |
| 2026-02-16 00:00 |
20:49:05.68 |
-19:14:29.4 |
HIP 102660 |
12.33 |
| 2026-02-16 12:00 |
20:49:10.74 |
-19:14:15.1 |
HIP 102726 |
13.51 |
| 2026-02-17 00:00 |
20:49:15.78 |
-19:14:01.0 |
HIP 102726 |
13.62 |
| 2026-02-17 12:00 |
20:49:20.80 |
-19:13:46.9 |
HIP 102726 |
13.84 |
| 2026-02-18 00:00 |
20:49:25.81 |
-19:13:32.9 |
HIP 102726 |
14.16 |
| 2026-02-18 12:00 |
20:49:30.80 |
-19:13:19.0 |
HIP 102726 |
14.57 |
| 2026-02-19 00:00 |
20:49:35.77 |
-19:13:05.1 |
HIP 102726 |
15.07 |
| 2026-02-19 12:00 |
20:49:40.73 |
-19:12:51.4 |
HIP 102726 |
15.64 |
| 2026-02-20 00:00 |
20:49:45.66 |
-19:12:37.7 |
HIP 102726 |
16.27 |
| 2026-02-20 12:00 |
20:49:50.58 |
-19:12:24.1 |
HIP 102726 |
16.96 |
| 2026-02-21 00:00 |
20:49:55.47 |
-19:12:10.6 |
HIP 102726 |
17.70 |
| 2026-02-21 12:00 |
20:50:00.34 |
-19:11:57.2 |
HIP 102726 |
18.49 |
| 2026-02-22 00:00 |
20:50:05.20 |
-19:11:43.9 |
HIP 102726 |
19.31 |
| 2026-02-22 12:00 |
20:50:10.03 |
-19:11:30.7 |
HIP 102726 |
20.16 |
| 2026-02-23 00:00 |
20:50:14.84 |
-19:11:17.6 |
HIP 102726 |
21.03 |
| 2026-02-23 12:00 |
20:50:19.62 |
-19:11:04.6 |
HIP 102726 |
21.93 |
| 2026-02-24 00:00 |
20:50:24.39 |
-19:10:51.7 |
HIP 102726 |
22.85 |