C/2024 B1 (Lemmon)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2024 B1 (Lemmon) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2024-10-07T16:58:54.436800Z |
| Orbit solution date (soln_date, UTC) | 2025-09-09T12:42:32Z |
| Obs used | 763 |
| NEO | - |
| M1 | 12.600 |
| K1 | 6.500 |
| PC | 0.030 |
| Discovery observation (MPC, UTC) | 2024-01-16T04:11:52.224000Z |
| Discovery magnitude (MPC) | 20.65 G |
| Discovery observatory (MPC) | G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2025-02-28.0000000 |
| e | 1.00088003 |
| q (au) | 1.633728 |
| a (au) | -1856.447475 |
| i (deg) | 70.903802 |
| Ω (om, deg) | 79.187466 |
| ω (w, deg) | 66.211826 |
| M (ma, deg) | 0.001766 |
Magnitude
Scatter + Global Linear
$$ M_a = (12.317 + 3.691\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 12.317 |
| n | 3.691 |
| gf | 1.000 |
| gb | -0.572 |
| 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 |
|---|---|---|---|
| 2023-10-13 | 2024-10-05 | +5.5116 | -1.105 |
| 2024-10-09 | 2025-01-21 | +0.2899 | -0.213 |
| 2025-01-21 | 2025-06-03 | +1.7670 | -0.947 |
| 2025-06-03 | 2025-08-19 | -1.4005 | +0.591 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 16:49:42.87 | -32:13:46.4 | HIP 82287 | 22.36 |
| 2026-09-20 12:00 | 16:49:49.20 | -32:14:12.2 | HIP 82287 | 23.42 |
| 2026-09-21 00:00 | 16:49:55.66 | -32:14:38.2 | HIP 82287 | 24.54 |
| 2026-09-21 12:00 | 16:50:02.25 | -32:15:04.3 | HIP 82287 | 25.70 |
| 2026-09-22 00:00 | 16:50:08.98 | -32:15:30.7 | HIP 82287 | 26.92 |
| 2026-09-22 12:00 | 16:50:15.83 | -32:15:57.3 | HIP 82287 | 28.18 |
| 2026-09-23 00:00 | 16:50:22.80 | -32:16:24.1 | HIP 82287 | 29.48 |
| 2026-09-23 12:00 | 16:50:29.91 | -32:16:51.1 | HIP 82287 | 30.83 |
| 2026-09-24 00:00 | 16:50:37.14 | -32:17:18.3 | HIP 82494 | 31.42 |
| 2026-09-24 12:00 | 16:50:44.49 | -32:17:45.7 | HIP 82494 | 30.43 |
| 2026-09-25 00:00 | 16:50:51.97 | -32:18:13.3 | HIP 82494 | 29.48 |
| 2026-09-25 12:00 | 16:50:59.57 | -32:18:41.1 | HIP 82494 | 28.58 |
| 2026-09-26 00:00 | 16:51:07.30 | -32:19:09.1 | HIP 82494 | 27.75 |
| 2026-09-26 12:00 | 16:51:15.15 | -32:19:37.3 | HIP 82494 | 26.99 |
| 2026-09-27 00:00 | 16:51:23.11 | -32:20:05.7 | HIP 82494 | 26.31 |
| 2026-09-27 12:00 | 16:51:31.20 | -32:20:34.3 | HIP 82494 | 25.73 |
| 2026-09-28 00:00 | 16:51:39.41 | -32:21:03.2 | HIP 82639 | 24.21 |
| 2026-09-28 12:00 | 16:51:47.73 | -32:21:32.2 | HIP 82639 | 22.46 |
| 2026-09-29 00:00 | 16:51:56.18 | -32:22:01.4 | HIP 82639 | 20.70 |
| 2026-09-29 12:00 | 16:52:04.74 | -32:22:30.8 | HIP 82639 | 18.94 |
| 2026-09-30 00:00 | 16:52:13.41 | -32:23:00.5 | HIP 82639 | 17.18 |
| 2026-09-30 12:00 | 16:52:22.21 | -32:23:30.3 | HIP 82639 | 15.42 |
| 2026-10-01 00:00 | 16:52:31.11 | -32:24:00.3 | HIP 82639 | 13.69 |
| 2026-10-01 12:00 | 16:52:40.13 | -32:24:30.6 | HIP 82639 | 12.00 |
| 2026-10-02 00:00 | 16:52:49.27 | -32:25:01.0 | HIP 82639 | 10.40 |
| 2026-10-02 12:00 | 16:52:58.52 | -32:25:31.6 | HIP 82639 | 8.93 |
| 2026-10-03 00:00 | 16:53:07.87 | -32:26:02.5 | HIP 82639 | 7.70 |
| 2026-10-03 12:00 | 16:53:17.35 | -32:26:33.5 | HIP 82639 | 6.86 |
| 2026-10-04 00:00 | 16:53:26.93 | -32:27:04.7 | HIP 82639 | 6.58 |
| 2026-10-04 12:00 | 16:53:36.62 | -32:27:36.2 | HIP 82639 | 6.95 |
| 2026-10-05 00:00 | 16:53:46.42 | -32:28:07.8 | HIP 82639 | 7.90 |
| 2026-10-05 12:00 | 16:53:56.33 | -32:28:39.6 | HIP 82639 | 9.27 |
| 2026-10-06 00:00 | 16:54:06.34 | -32:29:11.7 | HIP 82639 | 10.92 |
| 2026-10-06 12:00 | 16:54:16.46 | -32:29:43.9 | HIP 82639 | 12.74 |
| 2026-10-07 00:00 | 16:54:26.69 | -32:30:16.3 | HIP 82639 | 14.69 |
| 2026-10-07 12:00 | 16:54:37.03 | -32:30:49.0 | HIP 82639 | 16.73 |
| 2026-10-08 00:00 | 16:54:47.47 | -32:31:21.8 | HIP 82639 | 18.83 |
| 2026-10-08 12:00 | 16:54:58.01 | -32:31:54.8 | HIP 82738 | 20.84 |
| 2026-10-09 00:00 | 16:55:08.65 | -32:32:28.0 | HIP 82738 | 21.89 |
| 2026-10-09 12:00 | 16:55:19.40 | -32:33:01.4 | HIP 82738 | 23.13 |
| 2026-10-10 00:00 | 16:55:30.25 | -32:33:35.0 | HIP 82738 | 24.55 |
| 2026-10-10 12:00 | 16:55:41.19 | -32:34:08.9 | HIP 82738 | 26.11 |
| 2026-10-11 00:00 | 16:55:52.24 | -32:34:42.9 | HIP 82738 | 27.81 |