C/2007 U1 (LINEAR)
| Parameter |
Value |
| Designation |
C/2007 U1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-08-07T01:09:20.272320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:13Z |
| Obs used |
871 |
| NEO |
- |
| M1 |
10.300 |
| K1 |
7.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-09-04.0000000 |
| e |
1.00142595 |
| q (au) |
3.329202 |
| a (au) |
-2334.730148 |
| i (deg) |
157.786616 |
| Ω (om, deg) |
50.043135 |
| ω (w, deg) |
0.927038 |
| M (ma, deg) |
0.000244 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.173 + 3.897\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.173 |
| n |
3.897 |
| gf |
0.830 |
| gb |
-0.613 |
| k |
0.994 |
| δ90 |
5.330 |
| 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 |
| 2007-10-19 |
2008-02-05 |
+14.6988 |
-8.562 |
| 2008-02-05 |
2008-07-29 |
+6.0203 |
-3.221 |
| 2008-08-07 |
2009-11-18 |
-1.6673 |
+0.718 |
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 |
17:37:22.71 |
-11:05:25.5 |
HIP 86313 |
15.13 |
| 2026-02-03 12:00 |
17:37:24.72 |
-11:05:19.6 |
HIP 86313 |
14.69 |
| 2026-02-04 00:00 |
17:37:26.71 |
-11:05:13.7 |
HIP 86313 |
14.27 |
| 2026-02-04 12:00 |
17:37:28.68 |
-11:05:07.7 |
HIP 86313 |
13.85 |
| 2026-02-05 00:00 |
17:37:30.62 |
-11:05:01.7 |
HIP 86313 |
13.43 |
| 2026-02-05 12:00 |
17:37:32.54 |
-11:04:55.5 |
HIP 86313 |
13.03 |
| 2026-02-06 00:00 |
17:37:34.44 |
-11:04:49.3 |
HIP 86313 |
12.63 |
| 2026-02-06 12:00 |
17:37:36.31 |
-11:04:43.0 |
HIP 86313 |
12.25 |
| 2026-02-07 00:00 |
17:37:38.16 |
-11:04:36.7 |
HIP 86313 |
11.87 |
| 2026-02-07 12:00 |
17:37:39.99 |
-11:04:30.2 |
HIP 86313 |
11.50 |
| 2026-02-08 00:00 |
17:37:41.80 |
-11:04:23.7 |
HIP 86313 |
11.14 |
| 2026-02-08 12:00 |
17:37:43.58 |
-11:04:17.1 |
HIP 86313 |
10.79 |
| 2026-02-09 00:00 |
17:37:45.33 |
-11:04:10.5 |
HIP 86313 |
10.45 |
| 2026-02-09 12:00 |
17:37:47.07 |
-11:04:03.8 |
HIP 86313 |
10.12 |
| 2026-02-10 00:00 |
17:37:48.78 |
-11:03:57.0 |
HIP 86313 |
9.80 |
| 2026-02-10 12:00 |
17:37:50.46 |
-11:03:50.1 |
HIP 86313 |
9.49 |
| 2026-02-11 00:00 |
17:37:52.12 |
-11:03:43.2 |
HIP 86313 |
9.20 |
| 2026-02-11 12:00 |
17:37:53.76 |
-11:03:36.2 |
HIP 86313 |
8.91 |
| 2026-02-12 00:00 |
17:37:55.37 |
-11:03:29.1 |
HIP 86313 |
8.64 |
| 2026-02-12 12:00 |
17:37:56.95 |
-11:03:22.0 |
HIP 86313 |
8.38 |
| 2026-02-13 00:00 |
17:37:58.51 |
-11:03:14.8 |
HIP 86313 |
8.13 |
| 2026-02-13 12:00 |
17:38:00.05 |
-11:03:07.6 |
HIP 86313 |
7.90 |
| 2026-02-14 00:00 |
17:38:01.56 |
-11:03:00.2 |
HIP 86313 |
7.68 |
| 2026-02-14 12:00 |
17:38:03.04 |
-11:02:52.8 |
HIP 86313 |
7.48 |
| 2026-02-15 00:00 |
17:38:04.50 |
-11:02:45.4 |
HIP 86313 |
7.29 |
| 2026-02-15 12:00 |
17:38:05.93 |
-11:02:37.9 |
HIP 86313 |
7.11 |
| 2026-02-16 00:00 |
17:38:07.33 |
-11:02:30.3 |
HIP 86313 |
6.95 |
| 2026-02-16 12:00 |
17:38:08.71 |
-11:02:22.6 |
HIP 86313 |
6.81 |
| 2026-02-17 00:00 |
17:38:10.07 |
-11:02:14.9 |
HIP 86313 |
6.68 |
| 2026-02-17 12:00 |
17:38:11.39 |
-11:02:07.2 |
HIP 86313 |
6.56 |
| 2026-02-18 00:00 |
17:38:12.70 |
-11:01:59.3 |
HIP 86313 |
6.46 |
| 2026-02-18 12:00 |
17:38:13.97 |
-11:01:51.4 |
HIP 86313 |
6.38 |
| 2026-02-19 00:00 |
17:38:15.22 |
-11:01:43.5 |
HIP 86313 |
6.31 |
| 2026-02-19 12:00 |
17:38:16.44 |
-11:01:35.5 |
HIP 86313 |
6.25 |
| 2026-02-20 00:00 |
17:38:17.63 |
-11:01:27.4 |
HIP 86313 |
6.21 |
| 2026-02-20 12:00 |
17:38:18.79 |
-11:01:19.3 |
HIP 86313 |
6.18 |
| 2026-02-21 00:00 |
17:38:19.93 |
-11:01:11.2 |
HIP 86313 |
6.17 |
| 2026-02-21 12:00 |
17:38:21.04 |
-11:01:02.9 |
HIP 86313 |
6.16 |
| 2026-02-22 00:00 |
17:38:22.13 |
-11:00:54.6 |
HIP 86313 |
6.17 |
| 2026-02-22 12:00 |
17:38:23.18 |
-11:00:46.3 |
HIP 86313 |
6.19 |
| 2026-02-23 00:00 |
17:38:24.21 |
-11:00:37.9 |
HIP 86313 |
6.21 |
| 2026-02-23 12:00 |
17:38:25.21 |
-11:00:29.5 |
HIP 86313 |
6.25 |
| 2026-02-24 00:00 |
17:38:26.18 |
-11:00:21.0 |
HIP 86313 |
6.29 |