C/2002 T7 (LINEAR)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2002 T7 (LINEAR) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2004-04-23T01:29:19.495680Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:30:22Z |
| Obs used | 4397 |
| NEO | - |
| M1 | 7.600 |
| K1 | 6.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2003-11-16.0000000 |
| e | 1.00048628 |
| q (au) | 0.614546 |
| a (au) | -1263.766985 |
| i (deg) | 160.582715 |
| Ω (om, deg) | 94.856573 |
| ω (w, deg) | 157.739084 |
| M (ma, deg) | -0.003490 |
Magnitude
Scatter + Global Linear
$$ M_a = (6.176 + 3.575\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 6.176 |
| n | 3.575 |
| gf | 0.800 |
| gb | -0.500 |
| k | 0.800 |
| δ90 | 1.000 |
| 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 |
|---|---|---|---|
| 2001-01-14 | 2002-10-29 | -50.9308 | +42.214 |
| 2002-10-29 | 2004-04-22 | +0.0934 | -0.200 |
| 2004-04-23 | 2004-05-22 | +11.1569 | +2.707 |
| 2004-05-22 | 2006-03-20 | -0.3710 | +1.312 |
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 | 08:38:33.13 | +07:04:35.7 | HIP 42418 | 9.88 |
| 2026-09-20 12:00 | 08:38:34.69 | +07:04:24.0 | HIP 42418 | 9.48 |
| 2026-09-21 00:00 | 08:38:36.23 | +07:04:12.4 | HIP 42418 | 9.08 |
| 2026-09-21 12:00 | 08:38:37.75 | +07:04:00.7 | HIP 42418 | 8.69 |
| 2026-09-22 00:00 | 08:38:39.26 | +07:03:49.1 | HIP 42418 | 8.30 |
| 2026-09-22 12:00 | 08:38:40.75 | +07:03:37.5 | HIP 42418 | 7.92 |
| 2026-09-23 00:00 | 08:38:42.22 | +07:03:25.9 | HIP 42418 | 7.54 |
| 2026-09-23 12:00 | 08:38:43.67 | +07:03:14.3 | HIP 42418 | 7.17 |
| 2026-09-24 00:00 | 08:38:45.11 | +07:03:02.8 | HIP 42418 | 6.81 |
| 2026-09-24 12:00 | 08:38:46.53 | +07:02:51.3 | HIP 42418 | 6.46 |
| 2026-09-25 00:00 | 08:38:47.93 | +07:02:39.8 | HIP 42418 | 6.12 |
| 2026-09-25 12:00 | 08:38:49.32 | +07:02:28.3 | HIP 42418 | 5.78 |
| 2026-09-26 00:00 | 08:38:50.69 | +07:02:16.9 | HIP 42418 | 5.46 |
| 2026-09-26 12:00 | 08:38:52.04 | +07:02:05.5 | HIP 42418 | 5.15 |
| 2026-09-27 00:00 | 08:38:53.37 | +07:01:54.1 | HIP 42418 | 4.85 |
| 2026-09-27 12:00 | 08:38:54.68 | +07:01:42.8 | HIP 42418 | 4.56 |
| 2026-09-28 00:00 | 08:38:55.98 | +07:01:31.5 | HIP 42418 | 4.29 |
| 2026-09-28 12:00 | 08:38:57.26 | +07:01:20.2 | HIP 42418 | 4.04 |
| 2026-09-29 00:00 | 08:38:58.52 | +07:01:08.9 | HIP 42418 | 3.80 |
| 2026-09-29 12:00 | 08:38:59.76 | +07:00:57.7 | HIP 42418 | 3.59 |
| 2026-09-30 00:00 | 08:39:00.98 | +07:00:46.5 | HIP 42418 | 3.41 |
| 2026-09-30 12:00 | 08:39:02.19 | +07:00:35.4 | HIP 42418 | 3.25 |
| 2026-10-01 00:00 | 08:39:03.38 | +07:00:24.3 | HIP 42418 | 3.13 |
| 2026-10-01 12:00 | 08:39:04.54 | +07:00:13.2 | HIP 42418 | 3.04 |
| 2026-10-02 00:00 | 08:39:05.69 | +07:00:02.1 | HIP 42418 | 2.98 |
| 2026-10-02 12:00 | 08:39:06.82 | +06:59:51.1 | HIP 42418 | 2.96 |
| 2026-10-03 00:00 | 08:39:07.93 | +06:59:40.2 | HIP 42418 | 2.98 |
| 2026-10-03 12:00 | 08:39:09.02 | +06:59:29.2 | HIP 42418 | 3.03 |
| 2026-10-04 00:00 | 08:39:10.09 | +06:59:18.4 | HIP 42418 | 3.11 |
| 2026-10-04 12:00 | 08:39:11.15 | +06:59:07.5 | HIP 42418 | 3.21 |
| 2026-10-05 00:00 | 08:39:12.18 | +06:58:56.7 | HIP 42418 | 3.34 |
| 2026-10-05 12:00 | 08:39:13.19 | +06:58:46.0 | HIP 42418 | 3.49 |
| 2026-10-06 00:00 | 08:39:14.19 | +06:58:35.3 | HIP 42418 | 3.65 |
| 2026-10-06 12:00 | 08:39:15.16 | +06:58:24.6 | HIP 42418 | 3.83 |
| 2026-10-07 00:00 | 08:39:16.12 | +06:58:14.0 | HIP 42418 | 4.02 |
| 2026-10-07 12:00 | 08:39:17.05 | +06:58:03.4 | HIP 42418 | 4.21 |
| 2026-10-08 00:00 | 08:39:17.96 | +06:57:52.9 | HIP 42418 | 4.41 |
| 2026-10-08 12:00 | 08:39:18.86 | +06:57:42.4 | HIP 42418 | 4.62 |
| 2026-10-09 00:00 | 08:39:19.73 | +06:57:32.0 | HIP 42418 | 4.82 |
| 2026-10-09 12:00 | 08:39:20.58 | +06:57:21.6 | HIP 42418 | 5.03 |
| 2026-10-10 00:00 | 08:39:21.41 | +06:57:11.3 | HIP 42418 | 5.24 |
| 2026-10-10 12:00 | 08:39:22.23 | +06:57:01.0 | HIP 42418 | 5.45 |
| 2026-10-11 00:00 | 08:39:23.02 | +06:56:50.8 | HIP 42418 | 5.66 |