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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 08:34:43.80 | +07:24:08.4 | HIP 42000 | 23.95 |
| 2026-07-29 12:00 | 08:34:46.27 | +07:23:59.4 | HIP 42000 | 24.48 |
| 2026-07-30 00:00 | 08:34:48.74 | +07:23:50.4 | HIP 42000 | 25.01 |
| 2026-07-30 12:00 | 08:34:51.21 | +07:23:41.3 | HIP 42000 | 25.55 |
| 2026-07-31 00:00 | 08:34:53.68 | +07:23:32.1 | HIP 42000 | 26.10 |
| 2026-07-31 12:00 | 08:34:56.14 | +07:23:22.9 | HIP 42000 | 26.64 |
| 2026-08-01 00:00 | 08:34:58.61 | +07:23:13.6 | HIP 42194 | 27.09 |
| 2026-08-01 12:00 | 08:35:01.08 | +07:23:04.3 | HIP 42194 | 26.81 |
| 2026-08-02 00:00 | 08:35:03.54 | +07:22:54.9 | HIP 42194 | 26.53 |
| 2026-08-02 12:00 | 08:35:06.01 | +07:22:45.4 | HIP 42194 | 26.27 |
| 2026-08-03 00:00 | 08:35:08.47 | +07:22:35.9 | HIP 42194 | 26.03 |
| 2026-08-03 12:00 | 08:35:10.93 | +07:22:26.3 | HIP 42194 | 25.80 |
| 2026-08-04 00:00 | 08:35:13.39 | +07:22:16.6 | HIP 42194 | 25.58 |
| 2026-08-04 12:00 | 08:35:15.84 | +07:22:06.9 | HIP 42194 | 25.38 |
| 2026-08-05 00:00 | 08:35:18.30 | +07:21:57.2 | HIP 42194 | 25.19 |
| 2026-08-05 12:00 | 08:35:20.75 | +07:21:47.4 | HIP 42194 | 25.02 |
| 2026-08-06 00:00 | 08:35:23.20 | +07:21:37.5 | HIP 42194 | 24.86 |
| 2026-08-06 12:00 | 08:35:25.65 | +07:21:27.6 | HIP 42194 | 24.72 |
| 2026-08-07 00:00 | 08:35:28.10 | +07:21:17.6 | HIP 42194 | 24.60 |
| 2026-08-07 12:00 | 08:35:30.54 | +07:21:07.5 | HIP 42194 | 24.49 |
| 2026-08-08 00:00 | 08:35:32.98 | +07:20:57.4 | HIP 42194 | 24.40 |
| 2026-08-08 12:00 | 08:35:35.41 | +07:20:47.3 | HIP 42194 | 24.33 |
| 2026-08-09 00:00 | 08:35:37.85 | +07:20:37.1 | HIP 42194 | 24.28 |
| 2026-08-09 12:00 | 08:35:40.27 | +07:20:26.9 | HIP 42278 | 23.86 |
| 2026-08-10 00:00 | 08:35:42.70 | +07:20:16.6 | HIP 42278 | 23.33 |
| 2026-08-10 12:00 | 08:35:45.12 | +07:20:06.2 | HIP 42278 | 22.80 |
| 2026-08-11 00:00 | 08:35:47.54 | +07:19:55.8 | HIP 42278 | 22.28 |
| 2026-08-11 12:00 | 08:35:49.95 | +07:19:45.4 | HIP 42278 | 21.77 |
| 2026-08-12 00:00 | 08:35:52.36 | +07:19:34.9 | HIP 42278 | 21.27 |
| 2026-08-12 12:00 | 08:35:54.76 | +07:19:24.3 | HIP 42278 | 20.77 |
| 2026-08-13 00:00 | 08:35:57.16 | +07:19:13.7 | HIP 42278 | 20.28 |
| 2026-08-13 12:00 | 08:35:59.55 | +07:19:03.1 | HIP 42278 | 19.80 |
| 2026-08-14 00:00 | 08:36:01.94 | +07:18:52.4 | HIP 42278 | 19.33 |
| 2026-08-14 12:00 | 08:36:04.33 | +07:18:41.7 | HIP 42278 | 18.87 |
| 2026-08-15 00:00 | 08:36:06.70 | +07:18:31.0 | HIP 42278 | 18.42 |
| 2026-08-15 12:00 | 08:36:09.08 | +07:18:20.2 | HIP 42278 | 17.99 |
| 2026-08-16 00:00 | 08:36:11.44 | +07:18:09.3 | HIP 42278 | 17.56 |
| 2026-08-16 12:00 | 08:36:13.80 | +07:17:58.4 | HIP 42278 | 17.15 |
| 2026-08-17 00:00 | 08:36:16.15 | +07:17:47.5 | HIP 42278 | 16.75 |
| 2026-08-17 12:00 | 08:36:18.50 | +07:17:36.5 | HIP 42278 | 16.36 |
| 2026-08-18 00:00 | 08:36:20.84 | +07:17:25.5 | HIP 42278 | 16.00 |
| 2026-08-18 12:00 | 08:36:23.18 | +07:17:14.5 | HIP 42278 | 15.64 |
| 2026-08-19 00:00 | 08:36:25.50 | +07:17:03.4 | HIP 42278 | 15.31 |