| 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) |
| 2026-07-29 00:00 |
22:32:19.64 |
+05:03:50.2 |
HIP 111306 |
34.30 |
| 2026-07-29 12:00 |
22:32:06.66 |
+05:03:32.5 |
HIP 111306 |
35.59 |
| 2026-07-30 00:00 |
22:31:53.53 |
+05:03:13.4 |
HIP 111306 |
37.15 |
| 2026-07-30 12:00 |
22:31:40.26 |
+05:02:52.9 |
HIP 111306 |
38.96 |
| 2026-07-31 00:00 |
22:31:26.86 |
+05:02:31.1 |
HIP 111306 |
41.00 |
| 2026-07-31 12:00 |
22:31:13.31 |
+05:02:07.9 |
HIP 111062 |
40.79 |
| 2026-08-01 00:00 |
22:30:59.63 |
+05:01:43.3 |
HIP 111062 |
38.96 |
| 2026-08-01 12:00 |
22:30:45.82 |
+05:01:17.4 |
HIP 111062 |
37.32 |
| 2026-08-02 00:00 |
22:30:31.87 |
+05:00:50.1 |
HIP 111062 |
35.92 |
| 2026-08-02 12:00 |
22:30:17.79 |
+05:00:21.4 |
HIP 111062 |
34.79 |
| 2026-08-03 00:00 |
22:30:03.58 |
+04:59:51.3 |
HIP 111062 |
33.96 |
| 2026-08-03 12:00 |
22:29:49.24 |
+04:59:19.9 |
HIP 111062 |
33.48 |
| 2026-08-04 00:00 |
22:29:34.78 |
+04:58:47.1 |
HIP 110882 |
30.84 |
| 2026-08-04 12:00 |
22:29:20.19 |
+04:58:12.9 |
HIP 110882 |
27.54 |
| 2026-08-05 00:00 |
22:29:05.47 |
+04:57:37.4 |
HIP 110882 |
24.30 |
| 2026-08-05 12:00 |
22:28:50.63 |
+04:57:00.5 |
HIP 110882 |
21.19 |
| 2026-08-06 00:00 |
22:28:35.67 |
+04:56:22.2 |
HIP 110882 |
18.27 |
| 2026-08-06 12:00 |
22:28:20.59 |
+04:55:42.5 |
HIP 110882 |
15.70 |
| 2026-08-07 00:00 |
22:28:05.40 |
+04:55:01.5 |
HIP 110882 |
13.69 |
| 2026-08-07 12:00 |
22:27:50.09 |
+04:54:19.1 |
HIP 110882 |
12.54 |
| 2026-08-08 00:00 |
22:27:34.66 |
+04:53:35.4 |
HIP 110882 |
12.53 |
| 2026-08-08 12:00 |
22:27:19.13 |
+04:52:50.3 |
HIP 110882 |
13.68 |
| 2026-08-09 00:00 |
22:27:03.49 |
+04:52:03.8 |
HIP 110882 |
15.77 |
| 2026-08-09 12:00 |
22:26:47.73 |
+04:51:16.0 |
HIP 110776 |
15.12 |
| 2026-08-10 00:00 |
22:26:31.88 |
+04:50:26.9 |
HIP 110776 |
13.88 |
| 2026-08-10 12:00 |
22:26:15.92 |
+04:49:36.4 |
HIP 110686 |
12.56 |
| 2026-08-11 00:00 |
22:25:59.85 |
+04:48:44.5 |
HIP 110686 |
8.56 |
| 2026-08-11 12:00 |
22:25:43.69 |
+04:47:51.4 |
HIP 110686 |
4.68 |
| 2026-08-12 00:00 |
22:25:27.44 |
+04:46:56.9 |
HIP 110686 |
2.12 |
| 2026-08-12 12:00 |
22:25:11.09 |
+04:46:01.0 |
HIP 110686 |
4.66 |
| 2026-08-13 00:00 |
22:24:54.65 |
+04:45:03.9 |
HIP 110686 |
8.61 |
| 2026-08-13 12:00 |
22:24:38.12 |
+04:44:05.5 |
HIP 110686 |
12.75 |
| 2026-08-14 00:00 |
22:24:21.50 |
+04:43:05.7 |
HIP 110686 |
16.96 |
| 2026-08-14 12:00 |
22:24:04.80 |
+04:42:04.7 |
HIP 110686 |
21.22 |
| 2026-08-15 00:00 |
22:23:48.01 |
+04:41:02.3 |
HIP 110596 |
24.04 |
| 2026-08-15 12:00 |
22:23:31.15 |
+04:39:58.7 |
HIP 110596 |
26.71 |
| 2026-08-16 00:00 |
22:23:14.21 |
+04:38:53.9 |
HIP 110596 |
29.81 |
| 2026-08-16 12:00 |
22:22:57.20 |
+04:37:47.7 |
HIP 110596 |
33.21 |
| 2026-08-17 00:00 |
22:22:40.11 |
+04:36:40.4 |
HIP 110596 |
36.85 |
| 2026-08-17 12:00 |
22:22:22.96 |
+04:35:31.8 |
HIP 110596 |
40.67 |
| 2026-08-18 00:00 |
22:22:05.74 |
+04:34:21.9 |
HIP 110596 |
44.63 |
| 2026-08-18 12:00 |
22:21:48.45 |
+04:33:10.8 |
HIP 110596 |
48.69 |
| 2026-08-19 00:00 |
22:21:31.11 |
+04:31:58.5 |
HIP 110163 |
46.20 |