| 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) |
| 2026-07-29 00:00 |
12:49:05.22 |
-08:54:34.2 |
HIP 62551 |
18.68 |
| 2026-07-29 12:00 |
12:49:17.96 |
-08:55:29.6 |
HIP 62551 |
18.23 |
| 2026-07-30 00:00 |
12:49:30.80 |
-08:56:25.6 |
HIP 62551 |
18.37 |
| 2026-07-30 12:00 |
12:49:43.74 |
-08:57:22.4 |
HIP 62551 |
19.09 |
| 2026-07-31 00:00 |
12:49:56.79 |
-08:58:19.9 |
HIP 62551 |
20.34 |
| 2026-07-31 12:00 |
12:50:09.93 |
-08:59:18.1 |
HIP 62551 |
22.05 |
| 2026-08-01 00:00 |
12:50:23.17 |
-09:00:17.0 |
HIP 62551 |
24.13 |
| 2026-08-01 12:00 |
12:50:36.51 |
-09:01:16.5 |
HIP 62551 |
26.51 |
| 2026-08-02 00:00 |
12:50:49.95 |
-09:02:16.8 |
HIP 62551 |
29.12 |
| 2026-08-02 12:00 |
12:51:03.48 |
-09:03:17.8 |
HIP 62551 |
31.91 |
| 2026-08-03 00:00 |
12:51:17.11 |
-09:04:19.4 |
HIP 62844 |
30.85 |
| 2026-08-03 12:00 |
12:51:30.84 |
-09:05:21.7 |
HIP 62844 |
29.35 |
| 2026-08-04 00:00 |
12:51:44.66 |
-09:06:24.7 |
HIP 62844 |
28.21 |
| 2026-08-04 12:00 |
12:51:58.57 |
-09:07:28.4 |
HIP 62844 |
27.50 |
| 2026-08-05 00:00 |
12:52:12.58 |
-09:08:32.7 |
HIP 62844 |
27.25 |
| 2026-08-05 12:00 |
12:52:26.69 |
-09:09:37.7 |
HIP 62844 |
27.49 |
| 2026-08-06 00:00 |
12:52:40.88 |
-09:10:43.4 |
HIP 62844 |
28.21 |
| 2026-08-06 12:00 |
12:52:55.17 |
-09:11:49.7 |
HIP 62920 |
27.75 |
| 2026-08-07 00:00 |
12:53:09.55 |
-09:12:56.6 |
HIP 62920 |
25.42 |
| 2026-08-07 12:00 |
12:53:24.02 |
-09:14:04.2 |
HIP 62985 |
23.07 |
| 2026-08-08 00:00 |
12:53:38.58 |
-09:15:12.5 |
HIP 62985 |
20.09 |
| 2026-08-08 12:00 |
12:53:53.23 |
-09:16:21.3 |
HIP 62985 |
17.40 |
| 2026-08-09 00:00 |
12:54:07.97 |
-09:17:30.8 |
HIP 62985 |
15.18 |
| 2026-08-09 12:00 |
12:54:22.80 |
-09:18:41.0 |
HIP 62985 |
13.66 |
| 2026-08-10 00:00 |
12:54:37.72 |
-09:19:51.7 |
HIP 62985 |
13.12 |
| 2026-08-10 12:00 |
12:54:52.72 |
-09:21:03.1 |
HIP 62985 |
13.71 |
| 2026-08-11 00:00 |
12:55:07.81 |
-09:22:15.1 |
HIP 62985 |
15.30 |
| 2026-08-11 12:00 |
12:55:22.99 |
-09:23:27.7 |
HIP 62985 |
17.64 |
| 2026-08-12 00:00 |
12:55:38.25 |
-09:24:40.9 |
HIP 62985 |
20.49 |
| 2026-08-12 12:00 |
12:55:53.60 |
-09:25:54.7 |
HIP 62985 |
23.68 |
| 2026-08-13 00:00 |
12:56:09.03 |
-09:27:09.1 |
HIP 63240 |
26.96 |
| 2026-08-13 12:00 |
12:56:24.55 |
-09:28:24.1 |
HIP 63240 |
23.38 |
| 2026-08-14 00:00 |
12:56:40.15 |
-09:29:39.7 |
HIP 63240 |
19.96 |
| 2026-08-14 12:00 |
12:56:55.83 |
-09:30:55.8 |
HIP 63240 |
16.79 |
| 2026-08-15 00:00 |
12:57:11.59 |
-09:32:12.5 |
HIP 63240 |
14.09 |
| 2026-08-15 12:00 |
12:57:27.43 |
-09:33:29.8 |
HIP 63240 |
12.17 |
| 2026-08-16 00:00 |
12:57:43.35 |
-09:34:47.6 |
HIP 63240 |
11.46 |
| 2026-08-16 12:00 |
12:57:59.35 |
-09:36:06.0 |
HIP 63240 |
12.21 |
| 2026-08-17 00:00 |
12:58:15.43 |
-09:37:25.0 |
HIP 63240 |
14.20 |
| 2026-08-17 12:00 |
12:58:31.59 |
-09:38:44.5 |
HIP 63366 |
13.59 |
| 2026-08-18 00:00 |
12:58:47.82 |
-09:40:04.5 |
HIP 63366 |
10.60 |
| 2026-08-18 12:00 |
12:59:04.13 |
-09:41:25.1 |
HIP 63366 |
8.67 |
| 2026-08-19 00:00 |
12:59:20.51 |
-09:42:46.2 |
HIP 63366 |
8.60 |