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
$$ M_a = (6.175 + 3.576\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 6.175 |
| n | 3.576 |
| 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 | 2002-10-15 | -52.6508 | +43.995 |
| 2002-10-15 | 2004-04-22 | +0.0810 | -0.195 |
| 2004-04-23 | 2004-05-22 | +11.1309 | +2.705 |
| 2004-05-22 | 2006-03-20 | -0.3710 | +1.311 |
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 | 08:34:28.30 | +06:51:53.2 | HIP 42173 | 25.21 |
| 2026-02-03 12:00 | 08:34:25.50 | +06:52:05.1 | HIP 42173 | 25.89 |
| 2026-02-04 00:00 | 08:34:22.71 | +06:52:17.0 | HIP 42173 | 26.57 |
| 2026-02-04 12:00 | 08:34:19.92 | +06:52:29.1 | HIP 42173 | 27.26 |
| 2026-02-05 00:00 | 08:34:17.14 | +06:52:41.2 | HIP 42173 | 27.95 |
| 2026-02-05 12:00 | 08:34:14.36 | +06:52:53.3 | HIP 42173 | 28.64 |
| 2026-02-06 00:00 | 08:34:11.59 | +06:53:05.5 | HIP 42173 | 29.33 |
| 2026-02-06 12:00 | 08:34:08.82 | +06:53:17.7 | HIP 42173 | 30.02 |
| 2026-02-07 00:00 | 08:34:06.05 | +06:53:30.0 | HIP 42173 | 30.71 |
| 2026-02-07 12:00 | 08:34:03.29 | +06:53:42.4 | HIP 42173 | 31.40 |
| 2026-02-08 00:00 | 08:34:00.54 | +06:53:54.8 | HIP 42173 | 32.09 |
| 2026-02-08 12:00 | 08:33:57.79 | +06:54:07.3 | HIP 42173 | 32.78 |
| 2026-02-09 00:00 | 08:33:55.05 | +06:54:19.8 | HIP 42173 | 33.48 |
| 2026-02-09 12:00 | 08:33:52.31 | +06:54:32.4 | HIP 42173 | 34.17 |
| 2026-02-10 00:00 | 08:33:49.58 | +06:54:45.0 | HIP 42173 | 34.86 |
| 2026-02-10 12:00 | 08:33:46.85 | +06:54:57.7 | HIP 42173 | 35.55 |
| 2026-02-11 00:00 | 08:33:44.13 | +06:55:10.4 | HIP 42173 | 36.24 |
| 2026-02-11 12:00 | 08:33:41.42 | +06:55:23.1 | HIP 42173 | 36.94 |
| 2026-02-12 00:00 | 08:33:38.72 | +06:55:35.9 | HIP 41786 | 36.62 |
| 2026-02-12 12:00 | 08:33:36.02 | +06:55:48.8 | HIP 41786 | 35.93 |
| 2026-02-13 00:00 | 08:33:33.33 | +06:56:01.7 | HIP 41786 | 35.24 |
| 2026-02-13 12:00 | 08:33:30.65 | +06:56:14.6 | HIP 41786 | 34.55 |
| 2026-02-14 00:00 | 08:33:27.98 | +06:56:27.6 | HIP 41786 | 33.87 |
| 2026-02-14 12:00 | 08:33:25.31 | +06:56:40.6 | HIP 41786 | 33.19 |
| 2026-02-15 00:00 | 08:33:22.66 | +06:56:53.6 | HIP 41786 | 32.51 |
| 2026-02-15 12:00 | 08:33:20.01 | +06:57:06.7 | HIP 41786 | 31.83 |
| 2026-02-16 00:00 | 08:33:17.37 | +06:57:19.8 | HIP 41786 | 31.16 |
| 2026-02-16 12:00 | 08:33:14.74 | +06:57:33.0 | HIP 41786 | 30.49 |
| 2026-02-17 00:00 | 08:33:12.12 | +06:57:46.2 | HIP 41786 | 29.82 |
| 2026-02-17 12:00 | 08:33:09.51 | +06:57:59.4 | HIP 41786 | 29.15 |
| 2026-02-18 00:00 | 08:33:06.91 | +06:58:12.7 | HIP 41786 | 28.49 |
| 2026-02-18 12:00 | 08:33:04.32 | +06:58:26.0 | HIP 41786 | 27.84 |
| 2026-02-19 00:00 | 08:33:01.73 | +06:58:39.3 | HIP 41786 | 27.18 |
| 2026-02-19 12:00 | 08:32:59.16 | +06:58:52.6 | HIP 41786 | 26.53 |
| 2026-02-20 00:00 | 08:32:56.60 | +06:59:06.0 | HIP 41786 | 25.89 |
| 2026-02-20 12:00 | 08:32:54.05 | +06:59:19.4 | HIP 41786 | 25.24 |
| 2026-02-21 00:00 | 08:32:51.52 | +06:59:32.8 | HIP 41786 | 24.61 |
| 2026-02-21 12:00 | 08:32:48.99 | +06:59:46.3 | HIP 41786 | 23.97 |
| 2026-02-22 00:00 | 08:32:46.47 | +06:59:59.7 | HIP 41786 | 23.34 |
| 2026-02-22 12:00 | 08:32:43.97 | +07:00:13.2 | HIP 41786 | 22.72 |
| 2026-02-23 00:00 | 08:32:41.48 | +07:00:26.8 | HIP 41786 | 22.10 |
| 2026-02-23 12:00 | 08:32:39.00 | +07:00:40.3 | HIP 41786 | 21.49 |
| 2026-02-24 00:00 | 08:32:36.53 | +07:00:53.8 | HIP 41786 | 20.88 |