| 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) |
| 2026-07-29 00:00 |
13:02:50.76 |
-12:37:21.3 |
HIP 63709 |
22.86 |
| 2026-07-29 12:00 |
13:03:01.68 |
-12:38:25.9 |
HIP 63709 |
21.06 |
| 2026-07-30 00:00 |
13:03:12.72 |
-12:39:31.2 |
HIP 63709 |
19.49 |
| 2026-07-30 12:00 |
13:03:23.86 |
-12:40:37.3 |
HIP 63709 |
18.25 |
| 2026-07-31 00:00 |
13:03:35.12 |
-12:41:44.1 |
HIP 63709 |
17.41 |
| 2026-07-31 12:00 |
13:03:46.49 |
-12:42:51.6 |
HIP 63709 |
17.04 |
| 2026-08-01 00:00 |
13:03:57.97 |
-12:43:59.8 |
HIP 63709 |
17.20 |
| 2026-08-01 12:00 |
13:04:09.56 |
-12:45:08.8 |
HIP 63709 |
17.89 |
| 2026-08-02 00:00 |
13:04:21.26 |
-12:46:18.4 |
HIP 63709 |
19.05 |
| 2026-08-02 12:00 |
13:04:33.07 |
-12:47:28.7 |
HIP 63709 |
20.63 |
| 2026-08-03 00:00 |
13:04:44.98 |
-12:48:39.8 |
HIP 63709 |
22.55 |
| 2026-08-03 12:00 |
13:04:57.00 |
-12:49:51.5 |
HIP 63709 |
24.73 |
| 2026-08-04 00:00 |
13:05:09.13 |
-12:51:03.9 |
HIP 63789 |
26.75 |
| 2026-08-04 12:00 |
13:05:21.36 |
-12:52:17.0 |
HIP 63789 |
26.96 |
| 2026-08-05 00:00 |
13:05:33.70 |
-12:53:30.8 |
HIP 63789 |
27.55 |
| 2026-08-05 12:00 |
13:05:46.14 |
-12:54:45.3 |
HIP 64032 |
28.04 |
| 2026-08-06 00:00 |
13:05:58.69 |
-12:56:00.5 |
HIP 64032 |
26.23 |
| 2026-08-06 12:00 |
13:06:11.33 |
-12:57:16.3 |
HIP 64032 |
24.71 |
| 2026-08-07 00:00 |
13:06:24.09 |
-12:58:32.8 |
HIP 64032 |
23.56 |
| 2026-08-07 12:00 |
13:06:36.94 |
-12:59:49.9 |
HIP 64032 |
22.86 |
| 2026-08-08 00:00 |
13:06:49.89 |
-13:01:07.8 |
HIP 64093 |
19.52 |
| 2026-08-08 12:00 |
13:07:02.94 |
-13:02:26.2 |
HIP 64093 |
16.10 |
| 2026-08-09 00:00 |
13:07:16.10 |
-13:03:45.4 |
HIP 64093 |
12.65 |
| 2026-08-09 12:00 |
13:07:29.35 |
-13:05:05.2 |
HIP 64093 |
9.20 |
| 2026-08-10 00:00 |
13:07:42.70 |
-13:06:25.6 |
HIP 64093 |
5.77 |
| 2026-08-10 12:00 |
13:07:56.15 |
-13:07:46.7 |
HIP 64093 |
2.55 |
| 2026-08-11 00:00 |
13:08:09.69 |
-13:09:08.4 |
HIP 64093 |
2.22 |
| 2026-08-11 12:00 |
13:08:23.33 |
-13:10:30.7 |
HIP 64093 |
5.39 |
| 2026-08-12 00:00 |
13:08:37.07 |
-13:11:53.7 |
HIP 64093 |
8.91 |
| 2026-08-12 12:00 |
13:08:50.90 |
-13:13:17.3 |
HIP 64093 |
12.52 |
| 2026-08-13 00:00 |
13:09:04.83 |
-13:14:41.5 |
HIP 64156 |
11.91 |
| 2026-08-13 12:00 |
13:09:18.85 |
-13:16:06.4 |
HIP 64156 |
11.57 |
| 2026-08-14 00:00 |
13:09:32.96 |
-13:17:31.8 |
HIP 64156 |
12.39 |
| 2026-08-14 12:00 |
13:09:47.16 |
-13:18:57.9 |
HIP 64156 |
14.19 |
| 2026-08-15 00:00 |
13:10:01.45 |
-13:20:24.5 |
HIP 64156 |
16.66 |
| 2026-08-15 12:00 |
13:10:15.83 |
-13:21:51.7 |
HIP 64156 |
19.56 |
| 2026-08-16 00:00 |
13:10:30.30 |
-13:23:19.6 |
HIP 64156 |
22.75 |
| 2026-08-16 12:00 |
13:10:44.86 |
-13:24:48.0 |
HIP 64403 |
20.79 |
| 2026-08-17 00:00 |
13:10:59.51 |
-13:26:17.0 |
HIP 64403 |
16.97 |
| 2026-08-17 12:00 |
13:11:14.24 |
-13:27:46.6 |
HIP 64403 |
13.16 |
| 2026-08-18 00:00 |
13:11:29.06 |
-13:29:16.7 |
HIP 64403 |
9.38 |
| 2026-08-18 12:00 |
13:11:43.97 |
-13:30:47.4 |
HIP 64403 |
5.73 |
| 2026-08-19 00:00 |
13:11:58.95 |
-13:32:18.7 |
HIP 64403 |
2.94 |