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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 07:43:59.91 | +15:38:50.9 | HIP 37797 | 20.83 |
| 2026-07-29 12:00 | 07:44:24.99 | +15:37:34.0 | HIP 37797 | 18.27 |
| 2026-07-30 00:00 | 07:44:50.03 | +15:36:16.7 | HIP 37797 | 17.61 |
| 2026-07-30 12:00 | 07:45:15.03 | +15:34:59.1 | HIP 37797 | 19.04 |
| 2026-07-31 00:00 | 07:45:39.98 | +15:33:41.2 | HIP 37797 | 22.15 |
| 2026-07-31 12:00 | 07:46:04.90 | +15:32:23.0 | HIP 38005 | 18.72 |
| 2026-08-01 00:00 | 07:46:29.77 | +15:31:04.4 | HIP 38005 | 12.70 |
| 2026-08-01 12:00 | 07:46:54.59 | +15:29:45.6 | HIP 38005 | 6.88 |
| 2026-08-02 00:00 | 07:47:19.37 | +15:28:26.4 | HIP 38005 | 2.91 |
| 2026-08-02 12:00 | 07:47:44.11 | +15:27:06.8 | HIP 38005 | 6.65 |
| 2026-08-03 00:00 | 07:48:08.80 | +15:25:47.0 | HIP 38005 | 12.43 |
| 2026-08-03 12:00 | 07:48:33.44 | +15:24:26.8 | HIP 38005 | 18.40 |
| 2026-08-04 00:00 | 07:48:58.04 | +15:23:06.4 | HIP 38218 | 20.38 |
| 2026-08-04 12:00 | 07:49:22.59 | +15:21:45.6 | HIP 38218 | 16.41 |
| 2026-08-05 00:00 | 07:49:47.09 | +15:20:24.5 | HIP 38218 | 14.02 |
| 2026-08-05 12:00 | 07:50:11.55 | +15:19:03.1 | HIP 38218 | 14.04 |
| 2026-08-06 00:00 | 07:50:35.95 | +15:17:41.4 | HIP 38218 | 16.45 |
| 2026-08-06 12:00 | 07:51:00.30 | +15:16:19.4 | HIP 38218 | 20.41 |
| 2026-08-07 00:00 | 07:51:24.60 | +15:14:57.1 | HIP 38218 | 25.19 |
| 2026-08-07 12:00 | 07:51:48.85 | +15:13:34.5 | HIP 38503 | 20.56 |
| 2026-08-08 00:00 | 07:52:13.05 | +15:12:11.7 | HIP 38503 | 16.39 |
| 2026-08-08 12:00 | 07:52:37.19 | +15:10:48.5 | HIP 38503 | 13.65 |
| 2026-08-09 00:00 | 07:53:01.28 | +15:09:25.1 | HIP 38503 | 13.26 |
| 2026-08-09 12:00 | 07:53:25.32 | +15:08:01.3 | HIP 38524 | 13.05 |
| 2026-08-10 00:00 | 07:53:49.30 | +15:06:37.3 | HIP 38524 | 13.57 |
| 2026-08-10 12:00 | 07:54:13.22 | +15:05:13.1 | HIP 38524 | 16.39 |
| 2026-08-11 00:00 | 07:54:37.09 | +15:03:48.5 | HIP 38524 | 20.58 |
| 2026-08-11 12:00 | 07:55:00.90 | +15:02:23.7 | HIP 38638 | 24.16 |
| 2026-08-12 00:00 | 07:55:24.65 | +15:00:58.6 | HIP 38837 | 21.48 |
| 2026-08-12 12:00 | 07:55:48.34 | +14:59:33.3 | HIP 38837 | 15.63 |
| 2026-08-13 00:00 | 07:56:11.96 | +14:58:07.7 | HIP 38837 | 9.84 |
| 2026-08-13 12:00 | 07:56:35.53 | +14:56:41.9 | HIP 38837 | 4.34 |
| 2026-08-14 00:00 | 07:56:59.04 | +14:55:15.8 | HIP 38837 | 3.11 |
| 2026-08-14 12:00 | 07:57:22.48 | +14:53:49.5 | HIP 38837 | 8.30 |
| 2026-08-15 00:00 | 07:57:45.86 | +14:52:22.9 | HIP 38837 | 14.00 |
| 2026-08-15 12:00 | 07:58:09.17 | +14:50:56.2 | HIP 38837 | 19.76 |
| 2026-08-16 00:00 | 07:58:32.42 | +14:49:29.1 | HIP 38837 | 25.54 |
| 2026-08-16 12:00 | 07:58:55.60 | +14:48:01.9 | HIP 39178 | 28.56 |
| 2026-08-17 00:00 | 07:59:18.72 | +14:46:34.4 | HIP 39178 | 22.81 |
| 2026-08-17 12:00 | 07:59:41.77 | +14:45:06.7 | HIP 39178 | 17.08 |
| 2026-08-18 00:00 | 08:00:04.75 | +14:43:38.8 | HIP 39178 | 11.39 |
| 2026-08-18 12:00 | 08:00:27.66 | +14:42:10.7 | HIP 39178 | 5.84 |
| 2026-08-19 00:00 | 08:00:50.50 | +14:40:42.4 | HIP 39178 | 2.04 |