| Parameter |
Value |
| Designation |
C/2001 Q4 (NEAT) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-05-15T23:10:38.346240Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:11Z |
| Obs used |
2617 |
| NEO |
- |
| M1 |
8.000 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2004-05-15.0000000 |
| e |
1.00068805 |
| q (au) |
0.961960 |
| a (au) |
-1398.092298 |
| i (deg) |
99.642634 |
| Ω (om, deg) |
210.278440 |
| ω (w, deg) |
1.204371 |
| M (ma, deg) |
-0.000018 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.940 + 4.075\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.940 |
| n |
4.075 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
0.817 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2001-08-24 |
2004-03-09 |
-1.4351 |
-0.245 |
| 2004-03-09 |
2004-03-31 |
+6.4588 |
-1.163 |
| 2004-03-31 |
2004-05-15 |
-10.1442 |
+0.669 |
| 2004-05-15 |
2004-10-18 |
-1.2518 |
+0.669 |
| 2004-10-18 |
2006-08-18 |
+0.3692 |
+0.505 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
01:45:04.59 |
+27:46:57.1 |
HIP 8043 |
24.36 |
| 2026-07-29 12:00 |
01:45:04.21 |
+27:47:05.4 |
HIP 8043 |
24.26 |
| 2026-07-30 00:00 |
01:45:03.81 |
+27:47:13.6 |
HIP 8043 |
24.15 |
| 2026-07-30 12:00 |
01:45:03.38 |
+27:47:21.7 |
HIP 8043 |
24.04 |
| 2026-07-31 00:00 |
01:45:02.92 |
+27:47:29.7 |
HIP 8043 |
23.92 |
| 2026-07-31 12:00 |
01:45:02.45 |
+27:47:37.5 |
HIP 8043 |
23.80 |
| 2026-08-01 00:00 |
01:45:01.95 |
+27:47:45.2 |
HIP 8043 |
23.68 |
| 2026-08-01 12:00 |
01:45:01.42 |
+27:47:52.8 |
HIP 8043 |
23.55 |
| 2026-08-02 00:00 |
01:45:00.88 |
+27:48:00.2 |
HIP 8069 |
23.39 |
| 2026-08-02 12:00 |
01:45:00.30 |
+27:48:07.5 |
HIP 8069 |
23.22 |
| 2026-08-03 00:00 |
01:44:59.71 |
+27:48:14.7 |
HIP 8069 |
23.04 |
| 2026-08-03 12:00 |
01:44:59.09 |
+27:48:21.8 |
HIP 8069 |
22.86 |
| 2026-08-04 00:00 |
01:44:58.45 |
+27:48:28.7 |
HIP 8069 |
22.68 |
| 2026-08-04 12:00 |
01:44:57.78 |
+27:48:35.5 |
HIP 8069 |
22.49 |
| 2026-08-05 00:00 |
01:44:57.10 |
+27:48:42.1 |
HIP 8069 |
22.30 |
| 2026-08-05 12:00 |
01:44:56.38 |
+27:48:48.7 |
HIP 8069 |
22.11 |
| 2026-08-06 00:00 |
01:44:55.65 |
+27:48:55.0 |
HIP 8069 |
21.92 |
| 2026-08-06 12:00 |
01:44:54.89 |
+27:49:01.3 |
HIP 8069 |
21.73 |
| 2026-08-07 00:00 |
01:44:54.11 |
+27:49:07.4 |
HIP 8069 |
21.53 |
| 2026-08-07 12:00 |
01:44:53.30 |
+27:49:13.4 |
HIP 8069 |
21.33 |
| 2026-08-08 00:00 |
01:44:52.47 |
+27:49:19.2 |
HIP 8069 |
21.13 |
| 2026-08-08 12:00 |
01:44:51.62 |
+27:49:24.9 |
HIP 8069 |
20.92 |
| 2026-08-09 00:00 |
01:44:50.74 |
+27:49:30.4 |
HIP 8069 |
20.71 |
| 2026-08-09 12:00 |
01:44:49.84 |
+27:49:35.9 |
HIP 8069 |
20.51 |
| 2026-08-10 00:00 |
01:44:48.92 |
+27:49:41.1 |
HIP 8069 |
20.30 |
| 2026-08-10 12:00 |
01:44:47.97 |
+27:49:46.3 |
HIP 8069 |
20.08 |
| 2026-08-11 00:00 |
01:44:47.00 |
+27:49:51.2 |
HIP 8069 |
19.87 |
| 2026-08-11 12:00 |
01:44:46.01 |
+27:49:56.1 |
HIP 8069 |
19.65 |
| 2026-08-12 00:00 |
01:44:45.00 |
+27:50:00.8 |
HIP 8069 |
19.43 |
| 2026-08-12 12:00 |
01:44:43.96 |
+27:50:05.3 |
HIP 8069 |
19.21 |
| 2026-08-13 00:00 |
01:44:42.90 |
+27:50:09.7 |
HIP 8069 |
18.99 |
| 2026-08-13 12:00 |
01:44:41.81 |
+27:50:14.0 |
HIP 8069 |
18.77 |
| 2026-08-14 00:00 |
01:44:40.70 |
+27:50:18.1 |
HIP 8069 |
18.54 |
| 2026-08-14 12:00 |
01:44:39.57 |
+27:50:22.1 |
HIP 8069 |
18.32 |
| 2026-08-15 00:00 |
01:44:38.42 |
+27:50:25.9 |
HIP 8069 |
18.09 |
| 2026-08-15 12:00 |
01:44:37.25 |
+27:50:29.6 |
HIP 8069 |
17.87 |
| 2026-08-16 00:00 |
01:44:36.05 |
+27:50:33.1 |
HIP 8069 |
17.64 |
| 2026-08-16 12:00 |
01:44:34.83 |
+27:50:36.5 |
HIP 8069 |
17.41 |
| 2026-08-17 00:00 |
01:44:33.59 |
+27:50:39.7 |
HIP 8069 |
17.18 |
| 2026-08-17 12:00 |
01:44:32.33 |
+27:50:42.8 |
HIP 8069 |
16.95 |
| 2026-08-18 00:00 |
01:44:31.04 |
+27:50:45.7 |
HIP 8043 |
16.68 |
| 2026-08-18 12:00 |
01:44:29.73 |
+27:50:48.5 |
HIP 8043 |
16.39 |
| 2026-08-19 00:00 |
01:44:28.40 |
+27:50:51.1 |
HIP 8043 |
16.09 |