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 | 2020-06-29 | +13.7149 | -0.631 |
| 2020-06-29 | 2020-08-01 | +42.1296 | +3.341 |
| 2020-08-01 | 2021-01-18 | -1.3859 | +0.229 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 06:17:35.23 | +15:55:00.1 | HIP 29849 | 8.01 |
| 2026-02-03 12:00 | 06:17:15.58 | +15:55:43.6 | HIP 29849 | 5.20 |
| 2026-02-04 00:00 | 06:16:56.25 | +15:56:27.3 | HIP 29849 | 5.93 |
| 2026-02-04 12:00 | 06:16:37.24 | +15:57:11.0 | HIP 29849 | 9.30 |
| 2026-02-05 00:00 | 06:16:18.55 | +15:57:54.7 | HIP 29849 | 13.38 |
| 2026-02-05 12:00 | 06:16:00.19 | +15:58:38.5 | HIP 29704 | 13.04 |
| 2026-02-06 00:00 | 06:15:42.15 | +15:59:22.4 | HIP 29704 | 10.08 |
| 2026-02-06 12:00 | 06:15:24.43 | +16:00:06.4 | HIP 29704 | 8.49 |
| 2026-02-07 00:00 | 06:15:07.03 | +16:00:50.3 | HIP 29637 | 5.87 |
| 2026-02-07 12:00 | 06:14:49.96 | +16:01:34.4 | HIP 29637 | 1.73 |
| 2026-02-08 00:00 | 06:14:33.22 | +16:02:18.5 | HIP 29637 | 2.42 |
| 2026-02-08 12:00 | 06:14:16.80 | +16:03:02.6 | HIP 29637 | 6.42 |
| 2026-02-09 00:00 | 06:14:00.70 | +16:03:46.8 | HIP 29637 | 10.35 |
| 2026-02-09 12:00 | 06:13:44.94 | +16:04:31.0 | HIP 29637 | 14.20 |
| 2026-02-10 00:00 | 06:13:29.50 | +16:05:15.3 | HIP 29637 | 17.98 |
| 2026-02-10 12:00 | 06:13:14.39 | +16:05:59.5 | HIP 29434 | 17.18 |
| 2026-02-11 00:00 | 06:12:59.60 | +16:06:43.9 | HIP 29434 | 13.57 |
| 2026-02-11 12:00 | 06:12:45.14 | +16:07:28.2 | HIP 29434 | 10.06 |
| 2026-02-12 00:00 | 06:12:31.01 | +16:08:12.6 | HIP 29434 | 6.67 |
| 2026-02-12 12:00 | 06:12:17.21 | +16:08:56.9 | HIP 29434 | 3.53 |
| 2026-02-13 00:00 | 06:12:03.74 | +16:09:41.3 | HIP 29434 | 1.87 |
| 2026-02-13 12:00 | 06:11:50.59 | +16:10:25.7 | HIP 29434 | 4.01 |
| 2026-02-14 00:00 | 06:11:37.77 | +16:11:10.2 | HIP 29434 | 6.98 |
| 2026-02-14 12:00 | 06:11:25.28 | +16:11:54.6 | HIP 29434 | 10.00 |
| 2026-02-15 00:00 | 06:11:13.11 | +16:12:39.0 | HIP 29434 | 12.97 |
| 2026-02-15 12:00 | 06:11:01.27 | +16:13:23.4 | HIP 29434 | 15.89 |
| 2026-02-16 00:00 | 06:10:49.76 | +16:14:07.9 | HIP 29434 | 18.74 |
| 2026-02-16 12:00 | 06:10:38.58 | +16:14:52.3 | HIP 29274 | 21.22 |
| 2026-02-17 00:00 | 06:10:27.72 | +16:15:36.7 | HIP 29274 | 21.42 |
| 2026-02-17 12:00 | 06:10:17.18 | +16:16:21.1 | HIP 29274 | 21.96 |
| 2026-02-18 00:00 | 06:10:06.97 | +16:17:05.4 | HIP 29274 | 22.79 |
| 2026-02-18 12:00 | 06:09:57.09 | +16:17:49.8 | HIP 29187 | 23.44 |
| 2026-02-19 00:00 | 06:09:47.52 | +16:18:34.1 | HIP 29187 | 22.10 |
| 2026-02-19 12:00 | 06:09:38.28 | +16:19:18.4 | HIP 29187 | 20.96 |
| 2026-02-20 00:00 | 06:09:29.36 | +16:20:02.6 | HIP 29187 | 20.04 |
| 2026-02-20 12:00 | 06:09:20.77 | +16:20:46.8 | HIP 29187 | 19.33 |
| 2026-02-21 00:00 | 06:09:12.49 | +16:21:30.9 | HIP 29187 | 18.84 |
| 2026-02-21 12:00 | 06:09:04.53 | +16:22:15.0 | HIP 29187 | 18.56 |
| 2026-02-22 00:00 | 06:08:56.89 | +16:22:59.1 | HIP 29187 | 18.47 |
| 2026-02-22 12:00 | 06:08:49.56 | +16:23:43.1 | HIP 29187 | 18.56 |
| 2026-02-23 00:00 | 06:08:42.55 | +16:24:27.0 | HIP 29187 | 18.79 |
| 2026-02-23 12:00 | 06:08:35.86 | +16:25:10.9 | HIP 29187 | 19.16 |
| 2026-02-24 00:00 | 06:08:29.48 | +16:25:54.7 | HIP 29187 | 19.62 |