| 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) |
| 2026-09-20 00:00 |
01:42:22.85 |
+27:48:15.0 |
HIP 8043 |
11.89 |
| 2026-09-20 12:00 |
01:42:20.36 |
+27:48:07.4 |
HIP 8043 |
12.45 |
| 2026-09-21 00:00 |
01:42:17.85 |
+27:47:59.7 |
HIP 8043 |
13.02 |
| 2026-09-21 12:00 |
01:42:15.33 |
+27:47:51.8 |
HIP 8043 |
13.59 |
| 2026-09-22 00:00 |
01:42:12.80 |
+27:47:43.8 |
HIP 8043 |
14.17 |
| 2026-09-22 12:00 |
01:42:10.25 |
+27:47:35.6 |
HIP 8043 |
14.75 |
| 2026-09-23 00:00 |
01:42:07.70 |
+27:47:27.3 |
HIP 8043 |
15.33 |
| 2026-09-23 12:00 |
01:42:05.13 |
+27:47:18.8 |
HIP 8043 |
15.91 |
| 2026-09-24 00:00 |
01:42:02.55 |
+27:47:10.2 |
HIP 8043 |
16.50 |
| 2026-09-24 12:00 |
01:41:59.96 |
+27:47:01.4 |
HIP 8043 |
17.09 |
| 2026-09-25 00:00 |
01:41:57.36 |
+27:46:52.4 |
HIP 8043 |
17.69 |
| 2026-09-25 12:00 |
01:41:54.74 |
+27:46:43.4 |
HIP 8043 |
18.28 |
| 2026-09-26 00:00 |
01:41:52.12 |
+27:46:34.1 |
HIP 8043 |
18.88 |
| 2026-09-26 12:00 |
01:41:49.49 |
+27:46:24.7 |
HIP 8043 |
19.48 |
| 2026-09-27 00:00 |
01:41:46.84 |
+27:46:15.2 |
HIP 8043 |
20.09 |
| 2026-09-27 12:00 |
01:41:44.19 |
+27:46:05.5 |
HIP 8043 |
20.70 |
| 2026-09-28 00:00 |
01:41:41.52 |
+27:45:55.7 |
HIP 8043 |
21.31 |
| 2026-09-28 12:00 |
01:41:38.85 |
+27:45:45.7 |
HIP 8043 |
21.92 |
| 2026-09-29 00:00 |
01:41:36.17 |
+27:45:35.6 |
HIP 8043 |
22.54 |
| 2026-09-29 12:00 |
01:41:33.47 |
+27:45:25.3 |
HIP 8043 |
23.16 |
| 2026-09-30 00:00 |
01:41:30.77 |
+27:45:14.9 |
HIP 8043 |
23.78 |
| 2026-09-30 12:00 |
01:41:28.06 |
+27:45:04.4 |
HIP 8043 |
24.40 |
| 2026-10-01 00:00 |
01:41:25.34 |
+27:44:53.7 |
HIP 8043 |
25.03 |
| 2026-10-01 12:00 |
01:41:22.61 |
+27:44:42.8 |
HIP 8043 |
25.66 |
| 2026-10-02 00:00 |
01:41:19.87 |
+27:44:31.8 |
HIP 8043 |
26.29 |
| 2026-10-02 12:00 |
01:41:17.13 |
+27:44:20.7 |
HIP 8043 |
26.92 |
| 2026-10-03 00:00 |
01:41:14.38 |
+27:44:09.4 |
HIP 7708 |
26.60 |
| 2026-10-03 12:00 |
01:41:11.61 |
+27:43:58.0 |
HIP 7708 |
26.00 |
| 2026-10-04 00:00 |
01:41:08.85 |
+27:43:46.5 |
HIP 7708 |
25.40 |
| 2026-10-04 12:00 |
01:41:06.07 |
+27:43:34.8 |
HIP 7708 |
24.80 |
| 2026-10-05 00:00 |
01:41:03.29 |
+27:43:22.9 |
HIP 7708 |
24.20 |
| 2026-10-05 12:00 |
01:41:00.50 |
+27:43:10.9 |
HIP 7708 |
23.61 |
| 2026-10-06 00:00 |
01:40:57.70 |
+27:42:58.8 |
HIP 7708 |
23.01 |
| 2026-10-06 12:00 |
01:40:54.90 |
+27:42:46.6 |
HIP 7708 |
22.42 |
| 2026-10-07 00:00 |
01:40:52.09 |
+27:42:34.2 |
HIP 7708 |
21.83 |
| 2026-10-07 12:00 |
01:40:49.27 |
+27:42:21.6 |
HIP 7708 |
21.24 |
| 2026-10-08 00:00 |
01:40:46.45 |
+27:42:09.0 |
HIP 7708 |
20.65 |
| 2026-10-08 12:00 |
01:40:43.63 |
+27:41:56.2 |
HIP 7708 |
20.07 |
| 2026-10-09 00:00 |
01:40:40.79 |
+27:41:43.2 |
HIP 7708 |
19.49 |
| 2026-10-09 12:00 |
01:40:37.96 |
+27:41:30.2 |
HIP 7708 |
18.92 |
| 2026-10-10 00:00 |
01:40:35.11 |
+27:41:17.0 |
HIP 7708 |
18.36 |
| 2026-10-10 12:00 |
01:40:32.27 |
+27:41:03.6 |
HIP 7708 |
17.80 |
| 2026-10-11 00:00 |
01:40:29.42 |
+27:40:50.2 |
HIP 7708 |
17.24 |