| Parameter |
Value |
| Designation |
291P/NEAT |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-12-15T08:00:33.684480Z |
| Orbit solution date (soln_date, UTC) |
2024-05-30T01:12:35Z |
| Obs used |
950 |
| NEO |
- |
| M1 |
8.300 |
| K1 |
19.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-10-22.0000000 |
| e |
0.43049276 |
| q (au) |
2.591490 |
| a (au) |
4.550407 |
| i (deg) |
5.956694 |
| Ω (om, deg) |
241.044470 |
| ω (w, deg) |
176.028242 |
| M (ma, deg) |
317.421677 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.419 + 5.655\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.419 |
| n |
5.655 |
| gf |
0.807 |
| gb |
-0.768 |
| k |
0.973 |
| δ90 |
1.000 |
| 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 |
13:18:58.18 |
-11:24:00.9 |
HIP 65004 |
16.63 |
| 2026-09-20 12:00 |
13:19:18.18 |
-11:25:46.4 |
HIP 65023 |
15.93 |
| 2026-09-21 00:00 |
13:19:38.21 |
-11:27:32.1 |
HIP 65023 |
12.92 |
| 2026-09-21 12:00 |
13:19:58.28 |
-11:29:18.0 |
HIP 65023 |
11.61 |
| 2026-09-22 00:00 |
13:20:18.38 |
-11:31:04.1 |
HIP 65122 |
7.72 |
| 2026-09-22 12:00 |
13:20:38.52 |
-11:32:50.5 |
HIP 65122 |
6.05 |
| 2026-09-23 00:00 |
13:20:58.69 |
-11:34:37.0 |
HIP 65122 |
8.28 |
| 2026-09-23 12:00 |
13:21:18.89 |
-11:36:23.8 |
HIP 65191 |
9.34 |
| 2026-09-24 00:00 |
13:21:39.13 |
-11:38:10.7 |
HIP 65191 |
6.71 |
| 2026-09-24 12:00 |
13:21:59.39 |
-11:39:57.9 |
HIP 65191 |
7.63 |
| 2026-09-25 00:00 |
13:22:19.69 |
-11:41:45.2 |
HIP 65191 |
11.28 |
| 2026-09-25 12:00 |
13:22:40.02 |
-11:43:32.7 |
HIP 65191 |
15.88 |
| 2026-09-26 00:00 |
13:23:00.38 |
-11:45:20.4 |
HIP 65191 |
20.82 |
| 2026-09-26 12:00 |
13:23:20.76 |
-11:47:08.3 |
HIP 65191 |
25.90 |
| 2026-09-27 00:00 |
13:23:41.18 |
-11:48:56.3 |
HIP 65191 |
31.07 |
| 2026-09-27 12:00 |
13:24:01.63 |
-11:50:44.5 |
HIP 65191 |
36.28 |
| 2026-09-28 00:00 |
13:24:22.10 |
-11:52:32.9 |
HIP 65191 |
41.53 |
| 2026-09-28 12:00 |
13:24:42.60 |
-11:54:21.4 |
HIP 65474 |
45.24 |
| 2026-09-29 00:00 |
13:25:03.13 |
-11:56:10.1 |
HIP 65474 |
46.54 |
| 2026-09-29 12:00 |
13:25:23.68 |
-11:57:59.0 |
HIP 65474 |
48.40 |
| 2026-09-30 00:00 |
13:25:44.26 |
-11:59:48.0 |
HIP 65581 |
45.02 |
| 2026-09-30 12:00 |
13:26:04.87 |
-12:01:37.1 |
HIP 65581 |
41.90 |
| 2026-10-01 00:00 |
13:26:25.50 |
-12:03:26.4 |
HIP 65581 |
39.26 |
| 2026-10-01 12:00 |
13:26:46.16 |
-12:05:15.8 |
HIP 65581 |
37.20 |
| 2026-10-02 00:00 |
13:27:06.84 |
-12:07:05.4 |
HIP 65581 |
35.83 |
| 2026-10-02 12:00 |
13:27:27.54 |
-12:08:55.1 |
HIP 65724 |
32.18 |
| 2026-10-03 00:00 |
13:27:48.27 |
-12:10:44.9 |
HIP 65724 |
28.53 |
| 2026-10-03 12:00 |
13:28:09.02 |
-12:12:34.9 |
HIP 65724 |
25.49 |
| 2026-10-04 00:00 |
13:28:29.79 |
-12:14:25.0 |
HIP 65724 |
23.32 |
| 2026-10-04 12:00 |
13:28:50.58 |
-12:16:15.1 |
HIP 65724 |
22.28 |
| 2026-10-05 00:00 |
13:29:11.39 |
-12:18:05.4 |
HIP 65724 |
22.51 |
| 2026-10-05 12:00 |
13:29:32.23 |
-12:19:55.8 |
HIP 65724 |
24.00 |
| 2026-10-06 00:00 |
13:29:53.08 |
-12:21:46.4 |
HIP 65724 |
26.52 |
| 2026-10-06 12:00 |
13:30:13.95 |
-12:23:37.0 |
HIP 65724 |
29.83 |
| 2026-10-07 00:00 |
13:30:34.85 |
-12:25:27.7 |
HIP 66045 |
30.41 |
| 2026-10-07 12:00 |
13:30:55.76 |
-12:27:18.5 |
HIP 66045 |
25.05 |
| 2026-10-08 00:00 |
13:31:16.68 |
-12:29:09.3 |
HIP 66045 |
19.72 |
| 2026-10-08 12:00 |
13:31:37.62 |
-12:31:00.3 |
HIP 66045 |
14.47 |
| 2026-10-09 00:00 |
13:31:58.58 |
-12:32:51.3 |
HIP 66045 |
9.42 |
| 2026-10-09 12:00 |
13:32:19.56 |
-12:34:42.4 |
HIP 66045 |
5.23 |
| 2026-10-10 00:00 |
13:32:40.55 |
-12:36:33.6 |
HIP 66045 |
5.03 |
| 2026-10-10 12:00 |
13:33:01.55 |
-12:38:24.8 |
HIP 66045 |
9.08 |
| 2026-10-11 00:00 |
13:33:22.56 |
-12:40:16.1 |
HIP 66045 |
14.11 |