| Parameter |
Value |
| Designation |
C/2001 O2 (NEAT) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1999-10-17T08:10:25.610880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:10Z |
| Obs used |
73 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2001-09-20.0000000 |
| e |
0.99779815 |
| q (au) |
4.819418 |
| a (au) |
2188.798835 |
| i (deg) |
90.926212 |
| Ω (om, deg) |
328.716022 |
| ω (w, deg) |
280.894802 |
| M (ma, deg) |
0.006773 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.744 + 3.176\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.744 |
| n |
3.176 |
| gf |
0.893 |
| gb |
-0.966 |
| k |
1.000 |
| δ90 |
4.079 |
| 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 |
20:11:45.76 |
+47:17:29.7 |
HIP 99502 |
10.52 |
| 2026-07-29 12:00 |
20:11:41.96 |
+47:17:25.2 |
HIP 99502 |
10.37 |
| 2026-07-30 00:00 |
20:11:38.16 |
+47:17:20.5 |
HIP 99502 |
10.24 |
| 2026-07-30 12:00 |
20:11:34.37 |
+47:17:15.5 |
HIP 99502 |
10.16 |
| 2026-07-31 00:00 |
20:11:30.58 |
+47:17:10.1 |
HIP 99502 |
10.10 |
| 2026-07-31 12:00 |
20:11:26.79 |
+47:17:04.5 |
HIP 99502 |
10.09 |
| 2026-08-01 00:00 |
20:11:23.01 |
+47:16:58.5 |
HIP 99502 |
10.11 |
| 2026-08-01 12:00 |
20:11:19.23 |
+47:16:52.3 |
HIP 99502 |
10.17 |
| 2026-08-02 00:00 |
20:11:15.46 |
+47:16:45.7 |
HIP 99502 |
10.26 |
| 2026-08-02 12:00 |
20:11:11.69 |
+47:16:38.9 |
HIP 99502 |
10.39 |
| 2026-08-03 00:00 |
20:11:07.92 |
+47:16:31.7 |
HIP 99502 |
10.56 |
| 2026-08-03 12:00 |
20:11:04.17 |
+47:16:24.3 |
HIP 99502 |
10.75 |
| 2026-08-04 00:00 |
20:11:00.42 |
+47:16:16.5 |
HIP 99502 |
10.98 |
| 2026-08-04 12:00 |
20:10:56.67 |
+47:16:08.5 |
HIP 99502 |
11.23 |
| 2026-08-05 00:00 |
20:10:52.93 |
+47:16:00.1 |
HIP 99502 |
11.51 |
| 2026-08-05 12:00 |
20:10:49.20 |
+47:15:51.5 |
HIP 99502 |
11.82 |
| 2026-08-06 00:00 |
20:10:45.47 |
+47:15:42.6 |
HIP 99502 |
12.15 |
| 2026-08-06 12:00 |
20:10:41.75 |
+47:15:33.4 |
HIP 99502 |
12.50 |
| 2026-08-07 00:00 |
20:10:38.04 |
+47:15:23.8 |
HIP 99502 |
12.86 |
| 2026-08-07 12:00 |
20:10:34.34 |
+47:15:14.0 |
HIP 99502 |
13.25 |
| 2026-08-08 00:00 |
20:10:30.64 |
+47:15:03.9 |
HIP 99502 |
13.65 |
| 2026-08-08 12:00 |
20:10:26.96 |
+47:14:53.5 |
HIP 99502 |
14.07 |
| 2026-08-09 00:00 |
20:10:23.28 |
+47:14:42.8 |
HIP 99502 |
14.50 |
| 2026-08-09 12:00 |
20:10:19.61 |
+47:14:31.8 |
HIP 99502 |
14.94 |
| 2026-08-10 00:00 |
20:10:15.95 |
+47:14:20.6 |
HIP 99502 |
15.40 |
| 2026-08-10 12:00 |
20:10:12.30 |
+47:14:09.0 |
HIP 99502 |
15.86 |
| 2026-08-11 00:00 |
20:10:08.66 |
+47:13:57.2 |
HIP 99502 |
16.34 |
| 2026-08-11 12:00 |
20:10:05.03 |
+47:13:45.0 |
HIP 99502 |
16.82 |
| 2026-08-12 00:00 |
20:10:01.41 |
+47:13:32.6 |
HIP 99502 |
17.31 |
| 2026-08-12 12:00 |
20:09:57.80 |
+47:13:19.9 |
HIP 99502 |
17.80 |
| 2026-08-13 00:00 |
20:09:54.20 |
+47:13:06.9 |
HIP 99502 |
18.31 |
| 2026-08-13 12:00 |
20:09:50.61 |
+47:12:53.6 |
HIP 99502 |
18.81 |
| 2026-08-14 00:00 |
20:09:47.04 |
+47:12:40.1 |
HIP 99502 |
19.33 |
| 2026-08-14 12:00 |
20:09:43.47 |
+47:12:26.2 |
HIP 99502 |
19.85 |
| 2026-08-15 00:00 |
20:09:39.92 |
+47:12:12.1 |
HIP 99502 |
20.37 |
| 2026-08-15 12:00 |
20:09:36.38 |
+47:11:57.7 |
HIP 99502 |
20.90 |
| 2026-08-16 00:00 |
20:09:32.86 |
+47:11:43.0 |
HIP 99134 |
20.57 |
| 2026-08-16 12:00 |
20:09:29.34 |
+47:11:28.1 |
HIP 99134 |
19.94 |
| 2026-08-17 00:00 |
20:09:25.84 |
+47:11:12.9 |
HIP 99134 |
19.32 |
| 2026-08-17 12:00 |
20:09:22.36 |
+47:10:57.4 |
HIP 99134 |
18.70 |
| 2026-08-18 00:00 |
20:09:18.88 |
+47:10:41.6 |
HIP 99134 |
18.08 |
| 2026-08-18 12:00 |
20:09:15.42 |
+47:10:25.6 |
HIP 99134 |
17.47 |
| 2026-08-19 00:00 |
20:09:11.98 |
+47:10:09.3 |
HIP 99134 |
16.86 |