C/2012 BJ98 (Lemmon)
| Parameter |
Value |
| Designation |
C/2012 BJ98 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2012-09-20T10:27:43.799040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:00Z |
| Obs used |
155 |
| NEO |
- |
| M1 |
8.000 |
| K1 |
19.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-04-10.0000000 |
| e |
0.87364959 |
| q (au) |
2.156578 |
| a (au) |
17.068229 |
| i (deg) |
2.636892 |
| Ω (om, deg) |
124.031746 |
| ω (w, deg) |
72.969830 |
| M (ma, deg) |
357.715617 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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) |
| 2026-02-03 00:00 |
23:49:08.40 |
-03:25:25.2 |
HIP 117641 |
35.08 |
| 2026-02-03 12:00 |
23:49:12.16 |
-03:24:59.0 |
HIP 117641 |
34.13 |
| 2026-02-04 00:00 |
23:49:15.95 |
-03:24:32.6 |
HIP 117641 |
33.18 |
| 2026-02-04 12:00 |
23:49:19.76 |
-03:24:06.1 |
HIP 117641 |
32.22 |
| 2026-02-05 00:00 |
23:49:23.60 |
-03:23:39.5 |
HIP 117641 |
31.27 |
| 2026-02-05 12:00 |
23:49:27.46 |
-03:23:12.8 |
HIP 117641 |
30.32 |
| 2026-02-06 00:00 |
23:49:31.35 |
-03:22:45.9 |
HIP 117641 |
29.37 |
| 2026-02-06 12:00 |
23:49:35.26 |
-03:22:18.8 |
HIP 117641 |
28.42 |
| 2026-02-07 00:00 |
23:49:39.19 |
-03:21:51.7 |
HIP 117641 |
27.48 |
| 2026-02-07 12:00 |
23:49:43.15 |
-03:21:24.4 |
HIP 117641 |
26.54 |
| 2026-02-08 00:00 |
23:49:47.13 |
-03:20:56.9 |
HIP 117641 |
25.61 |
| 2026-02-08 12:00 |
23:49:51.13 |
-03:20:29.4 |
HIP 117641 |
24.68 |
| 2026-02-09 00:00 |
23:49:55.16 |
-03:20:01.7 |
HIP 117641 |
23.77 |
| 2026-02-09 12:00 |
23:49:59.20 |
-03:19:33.9 |
HIP 117641 |
22.86 |
| 2026-02-10 00:00 |
23:50:03.27 |
-03:19:06.0 |
HIP 117641 |
21.97 |
| 2026-02-10 12:00 |
23:50:07.36 |
-03:18:37.9 |
HIP 117641 |
21.10 |
| 2026-02-11 00:00 |
23:50:11.47 |
-03:18:09.8 |
HIP 117641 |
20.25 |
| 2026-02-11 12:00 |
23:50:15.61 |
-03:17:41.5 |
HIP 117641 |
19.42 |
| 2026-02-12 00:00 |
23:50:19.76 |
-03:17:13.1 |
HIP 117641 |
18.62 |
| 2026-02-12 12:00 |
23:50:23.93 |
-03:16:44.6 |
HIP 117641 |
17.86 |
| 2026-02-13 00:00 |
23:50:28.13 |
-03:16:15.9 |
HIP 117641 |
17.13 |
| 2026-02-13 12:00 |
23:50:32.34 |
-03:15:47.2 |
HIP 117641 |
16.44 |
| 2026-02-14 00:00 |
23:50:36.58 |
-03:15:18.4 |
HIP 117641 |
15.81 |
| 2026-02-14 12:00 |
23:50:40.83 |
-03:14:49.4 |
HIP 117641 |
15.24 |
| 2026-02-15 00:00 |
23:50:45.11 |
-03:14:20.4 |
HIP 117641 |
14.74 |
| 2026-02-15 12:00 |
23:50:49.40 |
-03:13:51.2 |
HIP 117641 |
14.31 |
| 2026-02-16 00:00 |
23:50:53.71 |
-03:13:22.0 |
HIP 117641 |
13.97 |
| 2026-02-16 12:00 |
23:50:58.04 |
-03:12:52.6 |
HIP 117641 |
13.72 |
| 2026-02-17 00:00 |
23:51:02.38 |
-03:12:23.2 |
HIP 117641 |
13.57 |
| 2026-02-17 12:00 |
23:51:06.75 |
-03:11:53.6 |
HIP 117641 |
13.52 |
| 2026-02-18 00:00 |
23:51:11.13 |
-03:11:24.0 |
HIP 117641 |
13.57 |
| 2026-02-18 12:00 |
23:51:15.53 |
-03:10:54.3 |
HIP 117641 |
13.74 |
| 2026-02-19 00:00 |
23:51:19.95 |
-03:10:24.4 |
HIP 117641 |
14.00 |
| 2026-02-19 12:00 |
23:51:24.38 |
-03:09:54.5 |
HIP 117641 |
14.37 |
| 2026-02-20 00:00 |
23:51:28.83 |
-03:09:24.6 |
HIP 117641 |
14.82 |
| 2026-02-20 12:00 |
23:51:33.29 |
-03:08:54.5 |
HIP 117641 |
15.36 |
| 2026-02-21 00:00 |
23:51:37.77 |
-03:08:24.4 |
HIP 117641 |
15.98 |
| 2026-02-21 12:00 |
23:51:42.27 |
-03:07:54.1 |
HIP 117641 |
16.67 |
| 2026-02-22 00:00 |
23:51:46.78 |
-03:07:23.9 |
HIP 117761 |
17.27 |
| 2026-02-22 12:00 |
23:51:51.30 |
-03:06:53.5 |
HIP 117761 |
16.21 |
| 2026-02-23 00:00 |
23:51:55.84 |
-03:06:23.1 |
HIP 117761 |
15.18 |
| 2026-02-23 12:00 |
23:52:00.39 |
-03:05:52.6 |
HIP 117761 |
14.19 |
| 2026-02-24 00:00 |
23:52:04.96 |
-03:05:22.0 |
HIP 117761 |
13.23 |