| Parameter |
Value |
| Designation |
C/2002 X1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2003-07-12T21:19:27.825600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:24Z |
| Obs used |
1432 |
| NEO |
- |
| M1 |
12.400 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-04-21.0000000 |
| e |
0.99818758 |
| q (au) |
2.486699 |
| a (au) |
1372.033208 |
| i (deg) |
164.089428 |
| Ω (om, deg) |
281.887134 |
| ω (w, deg) |
207.325128 |
| M (ma, deg) |
359.998392 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.579 + 2.717\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.579 |
| n |
2.717 |
| gf |
1.000 |
| gb |
-0.681 |
| k |
0.995 |
| δ90 |
9.999 |
| 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 |
| 2002-02-21 |
2003-05-02 |
-0.1664 |
-0.115 |
| 2003-08-03 |
2004-01-17 |
+21.3196 |
-9.226 |
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 |
18:50:31.49 |
-23:00:12.3 |
HIP 92503 |
8.47 |
| 2026-07-29 12:00 |
18:50:28.61 |
-23:00:15.2 |
HIP 92503 |
9.08 |
| 2026-07-30 00:00 |
18:50:25.74 |
-23:00:18.0 |
HIP 92503 |
9.69 |
| 2026-07-30 12:00 |
18:50:22.89 |
-23:00:20.8 |
HIP 92429 |
9.78 |
| 2026-07-31 00:00 |
18:50:20.04 |
-23:00:23.6 |
HIP 92429 |
9.68 |
| 2026-07-31 12:00 |
18:50:17.21 |
-23:00:26.4 |
HIP 92429 |
9.62 |
| 2026-08-01 00:00 |
18:50:14.39 |
-23:00:29.1 |
HIP 92429 |
9.61 |
| 2026-08-01 12:00 |
18:50:11.58 |
-23:00:31.8 |
HIP 92429 |
9.64 |
| 2026-08-02 00:00 |
18:50:08.78 |
-23:00:34.6 |
HIP 92429 |
9.71 |
| 2026-08-02 12:00 |
18:50:05.99 |
-23:00:37.3 |
HIP 92429 |
9.83 |
| 2026-08-03 00:00 |
18:50:03.22 |
-23:00:39.9 |
HIP 92429 |
9.98 |
| 2026-08-03 12:00 |
18:50:00.46 |
-23:00:42.6 |
HIP 92429 |
10.17 |
| 2026-08-04 00:00 |
18:49:57.72 |
-23:00:45.3 |
HIP 92429 |
10.40 |
| 2026-08-04 12:00 |
18:49:54.98 |
-23:00:47.9 |
HIP 92429 |
10.66 |
| 2026-08-05 00:00 |
18:49:52.26 |
-23:00:50.5 |
HIP 92429 |
10.94 |
| 2026-08-05 12:00 |
18:49:49.56 |
-23:00:53.1 |
HIP 92429 |
11.25 |
| 2026-08-06 00:00 |
18:49:46.87 |
-23:00:55.6 |
HIP 92429 |
11.59 |
| 2026-08-06 12:00 |
18:49:44.19 |
-23:00:58.2 |
HIP 92429 |
11.94 |
| 2026-08-07 00:00 |
18:49:41.52 |
-23:01:00.7 |
HIP 92429 |
12.32 |
| 2026-08-07 12:00 |
18:49:38.87 |
-23:01:03.2 |
HIP 92429 |
12.71 |
| 2026-08-08 00:00 |
18:49:36.24 |
-23:01:05.7 |
HIP 92429 |
13.11 |
| 2026-08-08 12:00 |
18:49:33.62 |
-23:01:08.2 |
HIP 92429 |
13.53 |
| 2026-08-09 00:00 |
18:49:31.01 |
-23:01:10.6 |
HIP 92429 |
13.96 |
| 2026-08-09 12:00 |
18:49:28.42 |
-23:01:13.1 |
HIP 92429 |
14.40 |
| 2026-08-10 00:00 |
18:49:25.85 |
-23:01:15.5 |
HIP 92429 |
14.85 |
| 2026-08-10 12:00 |
18:49:23.29 |
-23:01:17.9 |
HIP 92429 |
15.30 |
| 2026-08-11 00:00 |
18:49:20.75 |
-23:01:20.2 |
HIP 92429 |
15.76 |
| 2026-08-11 12:00 |
18:49:18.22 |
-23:01:22.6 |
HIP 92429 |
16.23 |
| 2026-08-12 00:00 |
18:49:15.71 |
-23:01:24.9 |
HIP 92429 |
16.70 |
| 2026-08-12 12:00 |
18:49:13.22 |
-23:01:27.2 |
HIP 92429 |
17.17 |
| 2026-08-13 00:00 |
18:49:10.74 |
-23:01:29.5 |
HIP 92429 |
17.65 |
| 2026-08-13 12:00 |
18:49:08.28 |
-23:01:31.7 |
HIP 92429 |
18.12 |
| 2026-08-14 00:00 |
18:49:05.83 |
-23:01:34.0 |
HIP 92429 |
18.60 |
| 2026-08-14 12:00 |
18:49:03.41 |
-23:01:36.2 |
HIP 92429 |
19.09 |
| 2026-08-15 00:00 |
18:49:01.00 |
-23:01:38.4 |
HIP 92429 |
19.57 |
| 2026-08-15 12:00 |
18:48:58.61 |
-23:01:40.5 |
HIP 92240 |
20.00 |
| 2026-08-16 00:00 |
18:48:56.23 |
-23:01:42.7 |
HIP 92240 |
19.58 |
| 2026-08-16 12:00 |
18:48:53.88 |
-23:01:44.8 |
HIP 92240 |
19.17 |
| 2026-08-17 00:00 |
18:48:51.54 |
-23:01:46.9 |
HIP 92240 |
18.78 |
| 2026-08-17 12:00 |
18:48:49.22 |
-23:01:49.0 |
HIP 92240 |
18.39 |
| 2026-08-18 00:00 |
18:48:46.91 |
-23:01:51.0 |
HIP 92240 |
18.01 |
| 2026-08-18 12:00 |
18:48:44.63 |
-23:01:53.0 |
HIP 92240 |
17.64 |
| 2026-08-19 00:00 |
18:48:42.37 |
-23:01:55.0 |
HIP 92240 |
17.29 |