| Parameter |
Value |
| Designation |
309P/LINEAR |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-02-16T06:54:37.134720Z |
| Orbit solution date (soln_date, UTC) |
2025-04-11T14:45:16Z |
| Obs used |
444 |
| NEO |
- |
| M1 |
16.200 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-11-28.0000000 |
| e |
0.60799848 |
| q (au) |
1.743209 |
| a (au) |
4.446944 |
| i (deg) |
17.665058 |
| Ω (om, deg) |
11.445885 |
| ω (w, deg) |
50.795718 |
| M (ma, deg) |
236.369621 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.080 + 2.428\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.080 |
| n |
2.428 |
| gf |
1.000 |
| gb |
-0.905 |
| k |
0.999 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
13:30:22.48 |
-15:25:46.7 |
HIP 65983 |
20.95 |
| 2026-09-20 12:00 |
13:30:41.51 |
-15:27:45.2 |
HIP 65983 |
18.07 |
| 2026-09-21 00:00 |
13:31:00.59 |
-15:29:44.0 |
HIP 65983 |
16.26 |
| 2026-09-21 12:00 |
13:31:19.71 |
-15:31:43.1 |
HIP 65983 |
15.88 |
| 2026-09-22 00:00 |
13:31:38.86 |
-15:33:42.5 |
HIP 65983 |
17.04 |
| 2026-09-22 12:00 |
13:31:58.06 |
-15:35:42.1 |
HIP 66091 |
18.99 |
| 2026-09-23 00:00 |
13:32:17.29 |
-15:37:42.1 |
HIP 66091 |
17.95 |
| 2026-09-23 12:00 |
13:32:36.56 |
-15:39:42.2 |
HIP 66091 |
18.29 |
| 2026-09-24 00:00 |
13:32:55.86 |
-15:41:42.6 |
HIP 66091 |
19.96 |
| 2026-09-24 12:00 |
13:33:15.21 |
-15:43:43.3 |
HIP 66091 |
22.66 |
| 2026-09-25 00:00 |
13:33:34.58 |
-15:45:44.2 |
HIP 66091 |
26.09 |
| 2026-09-25 12:00 |
13:33:54.00 |
-15:47:45.4 |
HIP 66091 |
30.00 |
| 2026-09-26 00:00 |
13:34:13.44 |
-15:49:46.8 |
HIP 66246 |
30.27 |
| 2026-09-26 12:00 |
13:34:32.93 |
-15:51:48.5 |
HIP 66246 |
27.62 |
| 2026-09-27 00:00 |
13:34:52.44 |
-15:53:50.4 |
HIP 66246 |
25.71 |
| 2026-09-27 12:00 |
13:35:11.99 |
-15:55:52.5 |
HIP 66246 |
24.73 |
| 2026-09-28 00:00 |
13:35:31.57 |
-15:57:54.9 |
HIP 66246 |
24.79 |
| 2026-09-28 12:00 |
13:35:51.18 |
-15:59:57.5 |
HIP 66246 |
25.88 |
| 2026-09-29 00:00 |
13:36:10.82 |
-16:02:00.3 |
HIP 66423 |
27.82 |
| 2026-09-29 12:00 |
13:36:30.50 |
-16:04:03.3 |
HIP 66423 |
24.08 |
| 2026-09-30 00:00 |
13:36:50.20 |
-16:06:06.5 |
HIP 66423 |
20.95 |
| 2026-09-30 12:00 |
13:37:09.94 |
-16:08:10.0 |
HIP 66423 |
18.73 |
| 2026-10-01 00:00 |
13:37:29.70 |
-16:10:13.7 |
HIP 66423 |
17.77 |
| 2026-10-01 12:00 |
13:37:49.49 |
-16:12:17.5 |
HIP 66423 |
18.29 |
| 2026-10-02 00:00 |
13:38:09.31 |
-16:14:21.6 |
HIP 66423 |
20.17 |
| 2026-10-02 12:00 |
13:38:29.16 |
-16:16:25.9 |
HIP 66423 |
23.09 |
| 2026-10-03 00:00 |
13:38:49.03 |
-16:18:30.4 |
HIP 66663 |
18.61 |
| 2026-10-03 12:00 |
13:39:08.93 |
-16:20:35.1 |
HIP 66663 |
13.41 |
| 2026-10-04 00:00 |
13:39:28.86 |
-16:22:40.0 |
HIP 66663 |
8.22 |
| 2026-10-04 12:00 |
13:39:48.81 |
-16:24:45.0 |
HIP 66663 |
3.10 |
| 2026-10-05 00:00 |
13:40:08.79 |
-16:26:50.3 |
HIP 66663 |
2.46 |
| 2026-10-05 12:00 |
13:40:28.79 |
-16:28:55.7 |
HIP 66663 |
7.57 |
| 2026-10-06 00:00 |
13:40:48.81 |
-16:31:01.3 |
HIP 66663 |
12.78 |
| 2026-10-06 12:00 |
13:41:08.86 |
-16:33:07.1 |
HIP 66663 |
18.01 |
| 2026-10-07 00:00 |
13:41:28.93 |
-16:35:13.0 |
HIP 66663 |
23.25 |
| 2026-10-07 12:00 |
13:41:49.02 |
-16:37:19.1 |
HIP 66811 |
26.84 |
| 2026-10-08 00:00 |
13:42:09.13 |
-16:39:25.4 |
HIP 66811 |
29.66 |
| 2026-10-08 12:00 |
13:42:29.26 |
-16:41:31.8 |
HIP 67055 |
30.44 |
| 2026-10-09 00:00 |
13:42:49.42 |
-16:43:38.4 |
HIP 67055 |
25.20 |
| 2026-10-09 12:00 |
13:43:09.59 |
-16:45:45.1 |
HIP 67055 |
19.96 |
| 2026-10-10 00:00 |
13:43:29.77 |
-16:47:52.0 |
HIP 67055 |
14.75 |
| 2026-10-10 12:00 |
13:43:49.98 |
-16:49:59.1 |
HIP 67055 |
9.60 |
| 2026-10-11 00:00 |
13:44:10.20 |
-16:52:06.2 |
HIP 67055 |
4.75 |