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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 08:22:14.70 | +13:02:18.7 | HIP 40956 | 17.37 |
| 2026-09-20 12:00 | 08:22:31.40 | +13:00:45.8 | HIP 40956 | 19.18 |
| 2026-09-21 00:00 | 08:22:47.98 | +12:59:12.9 | HIP 40956 | 21.70 |
| 2026-09-21 12:00 | 08:23:04.44 | +12:57:40.2 | HIP 40956 | 24.69 |
| 2026-09-22 00:00 | 08:23:20.78 | +12:56:07.5 | HIP 40956 | 28.00 |
| 2026-09-22 12:00 | 08:23:36.99 | +12:54:35.0 | HIP 40956 | 31.51 |
| 2026-09-23 00:00 | 08:23:53.07 | +12:53:02.6 | HIP 40956 | 35.16 |
| 2026-09-23 12:00 | 08:24:09.03 | +12:51:30.3 | HIP 40956 | 38.89 |
| 2026-09-24 00:00 | 08:24:24.86 | +12:49:58.1 | HIP 41400 | 35.56 |
| 2026-09-24 12:00 | 08:24:40.56 | +12:48:26.0 | HIP 41400 | 31.45 |
| 2026-09-25 00:00 | 08:24:56.13 | +12:46:54.1 | HIP 41400 | 27.37 |
| 2026-09-25 12:00 | 08:25:11.57 | +12:45:22.3 | HIP 41400 | 23.33 |
| 2026-09-26 00:00 | 08:25:26.88 | +12:43:50.6 | HIP 41400 | 19.34 |
| 2026-09-26 12:00 | 08:25:42.06 | +12:42:19.1 | HIP 41400 | 15.39 |
| 2026-09-27 00:00 | 08:25:57.11 | +12:40:47.8 | HIP 41400 | 11.52 |
| 2026-09-27 12:00 | 08:26:12.03 | +12:39:16.6 | HIP 41400 | 7.79 |
| 2026-09-28 00:00 | 08:26:26.81 | +12:37:45.6 | HIP 41400 | 4.45 |
| 2026-09-28 12:00 | 08:26:41.45 | +12:36:14.7 | HIP 41400 | 3.11 |
| 2026-09-29 00:00 | 08:26:55.96 | +12:34:44.0 | HIP 41400 | 5.42 |
| 2026-09-29 12:00 | 08:27:10.33 | +12:33:13.5 | HIP 41400 | 8.85 |
| 2026-09-30 00:00 | 08:27:24.57 | +12:31:43.2 | HIP 41400 | 12.47 |
| 2026-09-30 12:00 | 08:27:38.66 | +12:30:13.0 | HIP 41400 | 16.14 |
| 2026-10-01 00:00 | 08:27:52.62 | +12:28:43.1 | HIP 41474 | 18.55 |
| 2026-10-01 12:00 | 08:28:06.43 | +12:27:13.3 | HIP 41623 | 16.40 |
| 2026-10-02 00:00 | 08:28:20.10 | +12:25:43.8 | HIP 41623 | 14.07 |
| 2026-10-02 12:00 | 08:28:33.63 | +12:24:14.5 | HIP 41623 | 12.41 |
| 2026-10-03 00:00 | 08:28:47.02 | +12:22:45.4 | HIP 41623 | 11.69 |
| 2026-10-03 12:00 | 08:29:00.26 | +12:21:16.5 | HIP 41623 | 12.04 |
| 2026-10-04 00:00 | 08:29:13.35 | +12:19:47.8 | HIP 41623 | 13.36 |
| 2026-10-04 12:00 | 08:29:26.30 | +12:18:19.4 | HIP 41623 | 15.38 |
| 2026-10-05 00:00 | 08:29:39.09 | +12:16:51.3 | HIP 41623 | 17.83 |
| 2026-10-05 12:00 | 08:29:51.74 | +12:15:23.4 | HIP 41623 | 20.56 |
| 2026-10-06 00:00 | 08:30:04.24 | +12:13:55.7 | HIP 41623 | 23.44 |
| 2026-10-06 12:00 | 08:30:16.58 | +12:12:28.3 | HIP 41790 | 25.55 |
| 2026-10-07 00:00 | 08:30:28.77 | +12:11:01.2 | HIP 41790 | 22.73 |
| 2026-10-07 12:00 | 08:30:40.81 | +12:09:34.4 | HIP 41790 | 20.10 |
| 2026-10-08 00:00 | 08:30:52.69 | +12:08:07.9 | HIP 41790 | 17.69 |
| 2026-10-08 12:00 | 08:31:04.41 | +12:06:41.6 | HIP 41790 | 15.60 |
| 2026-10-09 00:00 | 08:31:15.98 | +12:05:15.7 | HIP 41790 | 13.95 |
| 2026-10-09 12:00 | 08:31:27.39 | +12:03:50.1 | HIP 41790 | 12.88 |
| 2026-10-10 00:00 | 08:31:38.64 | +12:02:24.8 | HIP 41790 | 12.51 |
| 2026-10-10 12:00 | 08:31:49.73 | +12:00:59.8 | HIP 41790 | 12.87 |
| 2026-10-11 00:00 | 08:32:00.65 | +11:59:35.1 | HIP 41790 | 13.88 |