| Parameter |
Value |
| Designation |
239P/LINEAR |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2019-01-09T23:17:42.864000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:01Z |
| Obs used |
365 |
| NEO |
- |
| M1 |
15.300 |
| K1 |
13.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-10-04.0000000 |
| e |
0.63143654 |
| q (au) |
1.647599 |
| a (au) |
4.470327 |
| i (deg) |
11.305620 |
| Ω (om, deg) |
255.944518 |
| ω (w, deg) |
220.383718 |
| M (ma, deg) |
273.660407 |
Magnitude
Scatter + Global Linear
$$
M_a = (18.785 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
18.785 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.656 |
| 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 |
| 2018-10-08 |
2019-01-09 |
+4.7782 |
-0.935 |
| 2019-01-11 |
2019-04-18 |
-10.8877 |
+2.304 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
22:38:47.87 |
+03:23:46.6 |
HIP 111779 |
5.56 |
| 2026-06-01 12:00 |
22:38:53.92 |
+03:25:31.6 |
HIP 111779 |
7.83 |
| 2026-06-02 00:00 |
22:38:59.82 |
+03:27:15.9 |
HIP 111779 |
10.08 |
| 2026-06-02 12:00 |
22:39:05.57 |
+03:28:59.6 |
HIP 111779 |
12.31 |
| 2026-06-03 00:00 |
22:39:11.18 |
+03:30:42.6 |
HIP 111779 |
14.50 |
| 2026-06-03 12:00 |
22:39:16.64 |
+03:32:25.0 |
HIP 111779 |
16.67 |
| 2026-06-04 00:00 |
22:39:21.96 |
+03:34:06.7 |
HIP 111779 |
18.81 |
| 2026-06-04 12:00 |
22:39:27.12 |
+03:35:47.7 |
HIP 111779 |
20.92 |
| 2026-06-05 00:00 |
22:39:32.14 |
+03:37:28.1 |
HIP 111779 |
23.00 |
| 2026-06-05 12:00 |
22:39:37.00 |
+03:39:07.8 |
HIP 111886 |
24.78 |
| 2026-06-06 00:00 |
22:39:41.71 |
+03:40:46.8 |
HIP 111888 |
26.27 |
| 2026-06-06 12:00 |
22:39:46.28 |
+03:42:25.1 |
HIP 111888 |
24.56 |
| 2026-06-07 00:00 |
22:39:50.68 |
+03:44:02.7 |
HIP 111888 |
22.91 |
| 2026-06-07 12:00 |
22:39:54.94 |
+03:45:39.5 |
HIP 111888 |
21.32 |
| 2026-06-08 00:00 |
22:39:59.04 |
+03:47:15.7 |
HIP 111888 |
19.80 |
| 2026-06-08 12:00 |
22:40:02.99 |
+03:48:51.1 |
HIP 111888 |
18.36 |
| 2026-06-09 00:00 |
22:40:06.78 |
+03:50:25.7 |
HIP 111888 |
17.00 |
| 2026-06-09 12:00 |
22:40:10.42 |
+03:51:59.6 |
HIP 111888 |
15.75 |
| 2026-06-10 00:00 |
22:40:13.90 |
+03:53:32.8 |
HIP 111888 |
14.60 |
| 2026-06-10 12:00 |
22:40:17.22 |
+03:55:05.1 |
HIP 111888 |
13.59 |
| 2026-06-11 00:00 |
22:40:20.38 |
+03:56:36.7 |
HIP 111888 |
12.72 |
| 2026-06-11 12:00 |
22:40:23.39 |
+03:58:07.6 |
HIP 111888 |
12.02 |
| 2026-06-12 00:00 |
22:40:26.23 |
+03:59:37.6 |
HIP 111888 |
11.50 |
| 2026-06-12 12:00 |
22:40:28.91 |
+04:01:06.8 |
HIP 111888 |
11.18 |
| 2026-06-13 00:00 |
22:40:31.44 |
+04:02:35.2 |
HIP 111888 |
11.06 |
| 2026-06-13 12:00 |
22:40:33.80 |
+04:04:02.8 |
HIP 111888 |
11.14 |
| 2026-06-14 00:00 |
22:40:36.00 |
+04:05:29.6 |
HIP 111888 |
11.40 |
| 2026-06-14 12:00 |
22:40:38.03 |
+04:06:55.5 |
HIP 111888 |
11.81 |
| 2026-06-15 00:00 |
22:40:39.90 |
+04:08:20.6 |
HIP 112007 |
11.72 |
| 2026-06-15 12:00 |
22:40:41.61 |
+04:09:44.8 |
HIP 112007 |
10.56 |
| 2026-06-16 00:00 |
22:40:43.16 |
+04:11:08.1 |
HIP 112007 |
9.53 |
| 2026-06-16 12:00 |
22:40:44.53 |
+04:12:30.6 |
HIP 112007 |
8.66 |
| 2026-06-17 00:00 |
22:40:45.75 |
+04:13:52.2 |
HIP 112007 |
7.99 |
| 2026-06-17 12:00 |
22:40:46.79 |
+04:15:13.0 |
HIP 112007 |
7.56 |
| 2026-06-18 00:00 |
22:40:47.67 |
+04:16:32.8 |
HIP 112007 |
7.41 |
| 2026-06-18 12:00 |
22:40:48.39 |
+04:17:51.7 |
HIP 112007 |
7.54 |
| 2026-06-19 00:00 |
22:40:48.94 |
+04:19:09.8 |
HIP 112007 |
7.92 |
| 2026-06-19 12:00 |
22:40:49.32 |
+04:20:26.9 |
HIP 112007 |
8.51 |
| 2026-06-20 00:00 |
22:40:49.53 |
+04:21:43.1 |
HIP 112007 |
9.27 |
| 2026-06-20 12:00 |
22:40:49.57 |
+04:22:58.3 |
HIP 112007 |
10.14 |
| 2026-06-21 00:00 |
22:40:49.45 |
+04:24:12.7 |
HIP 112007 |
11.11 |
| 2026-06-21 12:00 |
22:40:49.15 |
+04:25:26.1 |
HIP 111938 |
10.61 |
| 2026-06-22 00:00 |
22:40:48.69 |
+04:26:38.5 |
HIP 111938 |
9.53 |