C/2001 Q4 (NEAT)
| 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
$$
M_a = (5.940 + 4.076\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.940 |
| n |
4.076 |
| 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 |
-1.4286 |
-0.249 |
| 2004-03-09 |
2004-03-31 |
+6.5767 |
-1.177 |
| 2004-03-31 |
2004-05-15 |
-10.3221 |
+0.670 |
| 2004-05-15 |
2004-10-18 |
-1.2515 |
+0.669 |
| 2004-10-18 |
2006-08-18 |
+0.3689 |
+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) |
| 2026-02-03 00:00 |
01:34:09.66 |
+26:50:59.4 |
HIP 7406 |
19.83 |
| 2026-02-03 12:00 |
01:34:10.60 |
+26:50:51.1 |
HIP 7406 |
19.58 |
| 2026-02-04 00:00 |
01:34:11.56 |
+26:50:43.0 |
HIP 7406 |
19.33 |
| 2026-02-04 12:00 |
01:34:12.55 |
+26:50:35.1 |
HIP 7406 |
19.07 |
| 2026-02-05 00:00 |
01:34:13.56 |
+26:50:27.3 |
HIP 7406 |
18.81 |
| 2026-02-05 12:00 |
01:34:14.59 |
+26:50:19.6 |
HIP 7406 |
18.55 |
| 2026-02-06 00:00 |
01:34:15.65 |
+26:50:12.1 |
HIP 7406 |
18.28 |
| 2026-02-06 12:00 |
01:34:16.72 |
+26:50:04.8 |
HIP 7406 |
18.02 |
| 2026-02-07 00:00 |
01:34:17.82 |
+26:49:57.6 |
HIP 7406 |
17.74 |
| 2026-02-07 12:00 |
01:34:18.95 |
+26:49:50.6 |
HIP 7406 |
17.47 |
| 2026-02-08 00:00 |
01:34:20.09 |
+26:49:43.8 |
HIP 7406 |
17.19 |
| 2026-02-08 12:00 |
01:34:21.26 |
+26:49:37.1 |
HIP 7406 |
16.91 |
| 2026-02-09 00:00 |
01:34:22.45 |
+26:49:30.6 |
HIP 7406 |
16.62 |
| 2026-02-09 12:00 |
01:34:23.67 |
+26:49:24.2 |
HIP 7406 |
16.34 |
| 2026-02-10 00:00 |
01:34:24.90 |
+26:49:18.0 |
HIP 7406 |
16.05 |
| 2026-02-10 12:00 |
01:34:26.16 |
+26:49:12.0 |
HIP 7406 |
15.75 |
| 2026-02-11 00:00 |
01:34:27.44 |
+26:49:06.1 |
HIP 7406 |
15.46 |
| 2026-02-11 12:00 |
01:34:28.74 |
+26:49:00.4 |
HIP 7406 |
15.16 |
| 2026-02-12 00:00 |
01:34:30.07 |
+26:48:54.8 |
HIP 7406 |
14.86 |
| 2026-02-12 12:00 |
01:34:31.41 |
+26:48:49.4 |
HIP 7406 |
14.56 |
| 2026-02-13 00:00 |
01:34:32.78 |
+26:48:44.2 |
HIP 7406 |
14.25 |
| 2026-02-13 12:00 |
01:34:34.17 |
+26:48:39.1 |
HIP 7406 |
13.95 |
| 2026-02-14 00:00 |
01:34:35.58 |
+26:48:34.2 |
HIP 7406 |
13.64 |
| 2026-02-14 12:00 |
01:34:37.01 |
+26:48:29.5 |
HIP 7406 |
13.33 |
| 2026-02-15 00:00 |
01:34:38.47 |
+26:48:24.9 |
HIP 7406 |
13.02 |
| 2026-02-15 12:00 |
01:34:39.94 |
+26:48:20.5 |
HIP 7406 |
12.71 |
| 2026-02-16 00:00 |
01:34:41.43 |
+26:48:16.3 |
HIP 7406 |
12.39 |
| 2026-02-16 12:00 |
01:34:42.95 |
+26:48:12.2 |
HIP 7406 |
12.08 |
| 2026-02-17 00:00 |
01:34:44.49 |
+26:48:08.2 |
HIP 7406 |
11.76 |
| 2026-02-17 12:00 |
01:34:46.04 |
+26:48:04.5 |
HIP 7406 |
11.45 |
| 2026-02-18 00:00 |
01:34:47.62 |
+26:48:00.9 |
HIP 7406 |
11.14 |
| 2026-02-18 12:00 |
01:34:49.22 |
+26:47:57.4 |
HIP 7406 |
10.82 |
| 2026-02-19 00:00 |
01:34:50.84 |
+26:47:54.2 |
HIP 7406 |
10.51 |
| 2026-02-19 12:00 |
01:34:52.47 |
+26:47:51.1 |
HIP 7406 |
10.20 |
| 2026-02-20 00:00 |
01:34:54.13 |
+26:47:48.1 |
HIP 7406 |
9.90 |
| 2026-02-20 12:00 |
01:34:55.81 |
+26:47:45.3 |
HIP 7406 |
9.59 |
| 2026-02-21 00:00 |
01:34:57.51 |
+26:47:42.7 |
HIP 7406 |
9.29 |
| 2026-02-21 12:00 |
01:34:59.22 |
+26:47:40.3 |
HIP 7406 |
9.00 |
| 2026-02-22 00:00 |
01:35:00.96 |
+26:47:38.0 |
HIP 7406 |
8.71 |
| 2026-02-22 12:00 |
01:35:02.71 |
+26:47:35.8 |
HIP 7406 |
8.43 |
| 2026-02-23 00:00 |
01:35:04.49 |
+26:47:33.9 |
HIP 7406 |
8.16 |
| 2026-02-23 12:00 |
01:35:06.28 |
+26:47:32.1 |
HIP 7406 |
7.90 |
| 2026-02-24 00:00 |
01:35:08.09 |
+26:47:30.4 |
HIP 7406 |
7.65 |