C/2004 U1 (LINEAR)
| Parameter |
Value |
| Designation |
C/2004 U1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-12-08T18:11:10.507200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:44Z |
| Obs used |
545 |
| NEO |
- |
| M1 |
9.000 |
| K1 |
7.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-01-05.0000000 |
| e |
0.99920444 |
| q (au) |
2.659383 |
| a (au) |
3342.783641 |
| i (deg) |
130.623493 |
| Ω (om, deg) |
112.546364 |
| ω (w, deg) |
20.127932 |
| M (ma, deg) |
0.000139 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.689 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.689 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.832 |
| k |
0.800 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
19:59:04.21 |
-13:28:40.9 |
HIP 98352 |
10.89 |
| 2026-02-03 12:00 |
19:59:06.93 |
-13:28:33.4 |
HIP 98352 |
10.90 |
| 2026-02-04 00:00 |
19:59:09.65 |
-13:28:25.8 |
HIP 98352 |
10.95 |
| 2026-02-04 12:00 |
19:59:12.37 |
-13:28:18.2 |
HIP 98352 |
11.04 |
| 2026-02-05 00:00 |
19:59:15.07 |
-13:28:10.5 |
HIP 98352 |
11.17 |
| 2026-02-05 12:00 |
19:59:17.77 |
-13:28:02.8 |
HIP 98352 |
11.33 |
| 2026-02-06 00:00 |
19:59:20.46 |
-13:27:55.1 |
HIP 98352 |
11.53 |
| 2026-02-06 12:00 |
19:59:23.14 |
-13:27:47.4 |
HIP 98352 |
11.77 |
| 2026-02-07 00:00 |
19:59:25.82 |
-13:27:39.7 |
HIP 98352 |
12.03 |
| 2026-02-07 12:00 |
19:59:28.48 |
-13:27:31.9 |
HIP 98352 |
12.32 |
| 2026-02-08 00:00 |
19:59:31.14 |
-13:27:24.2 |
HIP 98352 |
12.64 |
| 2026-02-08 12:00 |
19:59:33.78 |
-13:27:16.4 |
HIP 98352 |
12.99 |
| 2026-02-09 00:00 |
19:59:36.42 |
-13:27:08.5 |
HIP 98352 |
13.35 |
| 2026-02-09 12:00 |
19:59:39.05 |
-13:27:00.7 |
HIP 98352 |
13.73 |
| 2026-02-10 00:00 |
19:59:41.67 |
-13:26:52.9 |
HIP 98352 |
14.14 |
| 2026-02-10 12:00 |
19:59:44.28 |
-13:26:45.0 |
HIP 98352 |
14.55 |
| 2026-02-11 00:00 |
19:59:46.88 |
-13:26:37.1 |
HIP 98352 |
14.99 |
| 2026-02-11 12:00 |
19:59:49.47 |
-13:26:29.2 |
HIP 98352 |
15.43 |
| 2026-02-12 00:00 |
19:59:52.05 |
-13:26:21.3 |
HIP 98352 |
15.89 |
| 2026-02-12 12:00 |
19:59:54.61 |
-13:26:13.3 |
HIP 98352 |
16.35 |
| 2026-02-13 00:00 |
19:59:57.17 |
-13:26:05.4 |
HIP 98352 |
16.83 |
| 2026-02-13 12:00 |
19:59:59.72 |
-13:25:57.4 |
HIP 98352 |
17.31 |
| 2026-02-14 00:00 |
20:00:02.25 |
-13:25:49.5 |
HIP 98352 |
17.80 |
| 2026-02-14 12:00 |
20:00:04.78 |
-13:25:41.5 |
HIP 98352 |
18.30 |
| 2026-02-15 00:00 |
20:00:07.29 |
-13:25:33.5 |
HIP 98352 |
18.80 |
| 2026-02-15 12:00 |
20:00:09.79 |
-13:25:25.5 |
HIP 98352 |
19.30 |
| 2026-02-16 00:00 |
20:00:12.28 |
-13:25:17.5 |
HIP 98352 |
19.81 |
| 2026-02-16 12:00 |
20:00:14.75 |
-13:25:09.5 |
HIP 98352 |
20.33 |
| 2026-02-17 00:00 |
20:00:17.22 |
-13:25:01.5 |
HIP 98352 |
20.84 |
| 2026-02-17 12:00 |
20:00:19.67 |
-13:24:53.4 |
HIP 98352 |
21.36 |
| 2026-02-18 00:00 |
20:00:22.11 |
-13:24:45.4 |
HIP 98352 |
21.88 |
| 2026-02-18 12:00 |
20:00:24.53 |
-13:24:37.4 |
HIP 98352 |
22.40 |
| 2026-02-19 00:00 |
20:00:26.95 |
-13:24:29.3 |
HIP 98352 |
22.93 |
| 2026-02-19 12:00 |
20:00:29.35 |
-13:24:21.3 |
HIP 98352 |
23.45 |
| 2026-02-20 00:00 |
20:00:31.73 |
-13:24:13.2 |
HIP 98352 |
23.97 |
| 2026-02-20 12:00 |
20:00:34.10 |
-13:24:05.2 |
HIP 98352 |
24.50 |
| 2026-02-21 00:00 |
20:00:36.46 |
-13:23:57.2 |
HIP 98633 |
24.54 |
| 2026-02-21 12:00 |
20:00:38.81 |
-13:23:49.1 |
HIP 98633 |
24.16 |
| 2026-02-22 00:00 |
20:00:41.14 |
-13:23:41.1 |
HIP 98633 |
23.79 |
| 2026-02-22 12:00 |
20:00:43.45 |
-13:23:33.0 |
HIP 98633 |
23.43 |
| 2026-02-23 00:00 |
20:00:45.75 |
-13:23:25.0 |
HIP 98633 |
23.09 |
| 2026-02-23 12:00 |
20:00:48.04 |
-13:23:17.0 |
HIP 98633 |
22.75 |
| 2026-02-24 00:00 |
20:00:50.31 |
-13:23:08.9 |
HIP 98633 |
22.43 |