249P/LINEAR
Metadata
| Parameter | Value |
|---|---|
| Designation | 249P/LINEAR |
| Type | P |
| Perihelion (tp_cal, UTC) | 2015-11-26T18:53:49.649280Z |
| Orbit solution date (soln_date, UTC) | 2023-01-03T10:14:16Z |
| Obs used | 884 |
| NEO | Yes |
| M1 | 18.400 |
| K1 | 4.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2014-07-25.0000000 |
| e | 0.81866843 |
| q (au) | 0.502345 |
| a (au) | 2.770312 |
| i (deg) | 8.399344 |
| Ω (om, deg) | 239.852044 |
| ω (w, deg) | 64.810358 |
| M (ma, deg) | 255.306758 |
Magnitude
Scatter + Global Linear
$$ M_a = (19.108 + 2.351\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 19.108 |
| n | 2.351 |
| gf | 1.000 |
| gb | -0.644 |
| 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 |
|---|---|---|---|
| 2020-01-25 | 2020-06-02 | +14.5622 | -0.412 |
| 2020-06-02 | 2020-08-01 | +43.3682 | +3.425 |
| 2020-08-01 | 2021-01-18 | -1.3785 | +0.228 |
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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 06:10:40.05 | +17:05:27.0 | HIP 29186 | 18.73 |
| 2026-03-26 12:00 | 06:10:49.75 | +17:06:00.0 | HIP 29186 | 20.81 |
| 2026-03-27 00:00 | 06:10:59.67 | +17:06:32.7 | HIP 29186 | 23.01 |
| 2026-03-27 12:00 | 06:11:09.80 | +17:07:05.1 | HIP 29186 | 25.30 |
| 2026-03-28 00:00 | 06:11:20.13 | +17:07:37.2 | HIP 29186 | 27.67 |
| 2026-03-28 12:00 | 06:11:30.67 | +17:08:09.1 | HIP 29186 | 30.11 |
| 2026-03-29 00:00 | 06:11:41.41 | +17:08:40.6 | HIP 29186 | 32.62 |
| 2026-03-29 12:00 | 06:11:52.35 | +17:09:11.8 | HIP 29591 | 33.24 |
| 2026-03-30 00:00 | 06:12:03.50 | +17:09:42.7 | HIP 29591 | 30.65 |
| 2026-03-30 12:00 | 06:12:14.83 | +17:10:13.3 | HIP 29591 | 28.03 |
| 2026-03-31 00:00 | 06:12:26.37 | +17:10:43.6 | HIP 29591 | 25.40 |
| 2026-03-31 12:00 | 06:12:38.10 | +17:11:13.6 | HIP 29591 | 22.76 |
| 2026-04-01 00:00 | 06:12:50.02 | +17:11:43.2 | HIP 29591 | 20.13 |
| 2026-04-01 12:00 | 06:13:02.13 | +17:12:12.5 | HIP 29591 | 17.54 |
| 2026-04-02 00:00 | 06:13:14.43 | +17:12:41.6 | HIP 29591 | 15.03 |
| 2026-04-02 12:00 | 06:13:26.92 | +17:13:10.2 | HIP 29591 | 12.69 |
| 2026-04-03 00:00 | 06:13:39.59 | +17:13:38.6 | HIP 29591 | 10.66 |
| 2026-04-03 12:00 | 06:13:52.45 | +17:14:06.6 | HIP 29591 | 9.20 |
| 2026-04-04 00:00 | 06:14:05.49 | +17:14:34.3 | HIP 29591 | 8.64 |
| 2026-04-04 12:00 | 06:14:18.71 | +17:15:01.7 | HIP 29591 | 9.19 |
| 2026-04-05 00:00 | 06:14:32.11 | +17:15:28.7 | HIP 29591 | 10.73 |
| 2026-04-05 12:00 | 06:14:45.69 | +17:15:55.3 | HIP 29591 | 12.93 |
| 2026-04-06 00:00 | 06:14:59.45 | +17:16:21.7 | HIP 29591 | 15.54 |
| 2026-04-06 12:00 | 06:15:13.38 | +17:16:47.7 | HIP 29798 | 17.82 |
| 2026-04-07 00:00 | 06:15:27.48 | +17:17:13.3 | HIP 29798 | 14.86 |
| 2026-04-07 12:00 | 06:15:41.76 | +17:17:38.6 | HIP 29798 | 12.09 |
| 2026-04-08 00:00 | 06:15:56.21 | +17:18:03.5 | HIP 29798 | 9.73 |
| 2026-04-08 12:00 | 06:16:10.82 | +17:18:28.0 | HIP 29798 | 8.18 |
| 2026-04-09 00:00 | 06:16:25.61 | +17:18:52.2 | HIP 29798 | 7.98 |
| 2026-04-09 12:00 | 06:16:40.56 | +17:19:16.1 | HIP 29828 | 7.62 |
| 2026-04-10 00:00 | 06:16:55.67 | +17:19:39.5 | HIP 29828 | 6.68 |
| 2026-04-10 12:00 | 06:17:10.95 | +17:20:02.6 | HIP 29828 | 7.60 |
| 2026-04-11 00:00 | 06:17:26.39 | +17:20:25.4 | HIP 29828 | 9.93 |
| 2026-04-11 12:00 | 06:17:41.99 | +17:20:47.7 | HIP 29828 | 12.95 |
| 2026-04-12 00:00 | 06:17:57.75 | +17:21:09.7 | HIP 30019 | 15.38 |
| 2026-04-12 12:00 | 06:18:13.67 | +17:21:31.3 | HIP 30019 | 11.67 |
| 2026-04-13 00:00 | 06:18:29.75 | +17:21:52.5 | HIP 30019 | 8.01 |
| 2026-04-13 12:00 | 06:18:45.98 | +17:22:13.3 | HIP 30019 | 4.65 |
| 2026-04-14 00:00 | 06:19:02.36 | +17:22:33.7 | HIP 30019 | 3.05 |
| 2026-04-14 12:00 | 06:19:18.90 | +17:22:53.7 | HIP 30019 | 5.29 |
| 2026-04-15 00:00 | 06:19:35.58 | +17:23:13.4 | HIP 30019 | 8.86 |
| 2026-04-15 12:00 | 06:19:52.42 | +17:23:32.6 | HIP 30019 | 12.72 |
| 2026-04-16 00:00 | 06:20:09.40 | +17:23:51.4 | HIP 30019 | 16.69 |