| 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) |
| 2026-05-12 00:00 |
00:03:33.21 |
-01:52:57.0 |
HIP 438 |
26.83 |
| 2026-05-12 12:00 |
00:03:36.49 |
-01:52:38.1 |
HIP 438 |
25.96 |
| 2026-05-13 00:00 |
00:03:39.74 |
-01:52:19.4 |
HIP 438 |
25.10 |
| 2026-05-13 12:00 |
00:03:42.96 |
-01:52:00.9 |
HIP 438 |
24.26 |
| 2026-05-14 00:00 |
00:03:46.15 |
-01:51:42.6 |
HIP 438 |
23.42 |
| 2026-05-14 12:00 |
00:03:49.32 |
-01:51:24.5 |
HIP 438 |
22.59 |
| 2026-05-15 00:00 |
00:03:52.46 |
-01:51:06.6 |
HIP 438 |
21.76 |
| 2026-05-15 12:00 |
00:03:55.56 |
-01:50:48.9 |
HIP 438 |
20.95 |
| 2026-05-16 00:00 |
00:03:58.64 |
-01:50:31.4 |
HIP 438 |
20.15 |
| 2026-05-16 12:00 |
00:04:01.69 |
-01:50:14.1 |
HIP 438 |
19.35 |
| 2026-05-17 00:00 |
00:04:04.71 |
-01:49:57.0 |
HIP 438 |
18.57 |
| 2026-05-17 12:00 |
00:04:07.70 |
-01:49:40.1 |
HIP 438 |
17.79 |
| 2026-05-18 00:00 |
00:04:10.66 |
-01:49:23.4 |
HIP 438 |
17.03 |
| 2026-05-18 12:00 |
00:04:13.59 |
-01:49:07.0 |
HIP 438 |
16.27 |
| 2026-05-19 00:00 |
00:04:16.49 |
-01:48:50.7 |
HIP 438 |
15.53 |
| 2026-05-19 12:00 |
00:04:19.36 |
-01:48:34.7 |
HIP 438 |
14.79 |
| 2026-05-20 00:00 |
00:04:22.20 |
-01:48:18.9 |
HIP 438 |
14.07 |
| 2026-05-20 12:00 |
00:04:25.01 |
-01:48:03.3 |
HIP 438 |
13.36 |
| 2026-05-21 00:00 |
00:04:27.78 |
-01:47:47.9 |
HIP 438 |
12.66 |
| 2026-05-21 12:00 |
00:04:30.53 |
-01:47:32.8 |
HIP 438 |
11.97 |
| 2026-05-22 00:00 |
00:04:33.24 |
-01:47:17.8 |
HIP 438 |
11.30 |
| 2026-05-22 12:00 |
00:04:35.92 |
-01:47:03.1 |
HIP 438 |
10.64 |
| 2026-05-23 00:00 |
00:04:38.57 |
-01:46:48.6 |
HIP 438 |
10.00 |
| 2026-05-23 12:00 |
00:04:41.19 |
-01:46:34.3 |
HIP 438 |
9.37 |
| 2026-05-24 00:00 |
00:04:43.78 |
-01:46:20.2 |
HIP 438 |
8.76 |
| 2026-05-24 12:00 |
00:04:46.33 |
-01:46:06.4 |
HIP 438 |
8.17 |
| 2026-05-25 00:00 |
00:04:48.85 |
-01:45:52.8 |
HIP 438 |
7.60 |
| 2026-05-25 12:00 |
00:04:51.34 |
-01:45:39.4 |
HIP 438 |
7.06 |
| 2026-05-26 00:00 |
00:04:53.80 |
-01:45:26.2 |
HIP 438 |
6.54 |
| 2026-05-26 12:00 |
00:04:56.22 |
-01:45:13.2 |
HIP 438 |
6.06 |
| 2026-05-27 00:00 |
00:04:58.61 |
-01:45:00.5 |
HIP 438 |
5.62 |
| 2026-05-27 12:00 |
00:05:00.97 |
-01:44:48.0 |
HIP 438 |
5.21 |
| 2026-05-28 00:00 |
00:05:03.30 |
-01:44:35.7 |
HIP 438 |
4.86 |
| 2026-05-28 12:00 |
00:05:05.59 |
-01:44:23.7 |
HIP 438 |
4.57 |
| 2026-05-29 00:00 |
00:05:07.85 |
-01:44:11.8 |
HIP 438 |
4.35 |
| 2026-05-29 12:00 |
00:05:10.07 |
-01:44:00.3 |
HIP 438 |
4.20 |
| 2026-05-30 00:00 |
00:05:12.26 |
-01:43:48.9 |
HIP 438 |
4.13 |
| 2026-05-30 12:00 |
00:05:14.42 |
-01:43:37.8 |
HIP 438 |
4.14 |
| 2026-05-31 00:00 |
00:05:16.55 |
-01:43:26.9 |
HIP 438 |
4.23 |
| 2026-05-31 12:00 |
00:05:18.64 |
-01:43:16.2 |
HIP 438 |
4.38 |
| 2026-06-01 00:00 |
00:05:20.69 |
-01:43:05.7 |
HIP 438 |
4.59 |
| 2026-06-01 12:00 |
00:05:22.71 |
-01:42:55.5 |
HIP 438 |
4.84 |
| 2026-06-02 00:00 |
00:05:24.70 |
-01:42:45.6 |
HIP 438 |
5.13 |