| Parameter |
Value |
| Designation |
C/2013 TW5 (Spacewatch) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2014-08-17T15:50:25.054080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:41Z |
| Obs used |
421 |
| NEO |
- |
| M1 |
11.000 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2014-06-23.0000000 |
| e |
0.98693812 |
| q (au) |
5.830627 |
| a (au) |
446.385044 |
| i (deg) |
31.401407 |
| Ω (om, deg) |
319.703831 |
| ω (w, deg) |
190.375424 |
| M (ma, deg) |
359.994183 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.679 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.679 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.728 |
| k |
0.800 |
| δ90 |
10.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
18:49:03.54 |
-45:36:47.0 |
HIP 92345 |
9.53 |
| 2026-03-26 12:00 |
18:49:05.20 |
-45:37:09.8 |
HIP 92345 |
9.10 |
| 2026-03-27 00:00 |
18:49:06.80 |
-45:37:32.6 |
HIP 92345 |
8.68 |
| 2026-03-27 12:00 |
18:49:08.34 |
-45:37:55.4 |
HIP 92345 |
8.27 |
| 2026-03-28 00:00 |
18:49:09.82 |
-45:38:18.4 |
HIP 92345 |
7.86 |
| 2026-03-28 12:00 |
18:49:11.24 |
-45:38:41.4 |
HIP 92345 |
7.46 |
| 2026-03-29 00:00 |
18:49:12.60 |
-45:39:04.5 |
HIP 92345 |
7.06 |
| 2026-03-29 12:00 |
18:49:13.90 |
-45:39:27.7 |
HIP 92345 |
6.67 |
| 2026-03-30 00:00 |
18:49:15.14 |
-45:39:51.0 |
HIP 92345 |
6.28 |
| 2026-03-30 12:00 |
18:49:16.32 |
-45:40:14.3 |
HIP 92345 |
5.90 |
| 2026-03-31 00:00 |
18:49:17.45 |
-45:40:37.7 |
HIP 92345 |
5.53 |
| 2026-03-31 12:00 |
18:49:18.51 |
-45:41:01.2 |
HIP 92345 |
5.17 |
| 2026-04-01 00:00 |
18:49:19.51 |
-45:41:24.7 |
HIP 92345 |
4.81 |
| 2026-04-01 12:00 |
18:49:20.46 |
-45:41:48.3 |
HIP 92345 |
4.46 |
| 2026-04-02 00:00 |
18:49:21.34 |
-45:42:11.9 |
HIP 92345 |
4.13 |
| 2026-04-02 12:00 |
18:49:22.16 |
-45:42:35.6 |
HIP 92345 |
3.80 |
| 2026-04-03 00:00 |
18:49:22.93 |
-45:42:59.4 |
HIP 92345 |
3.49 |
| 2026-04-03 12:00 |
18:49:23.63 |
-45:43:23.2 |
HIP 92345 |
3.20 |
| 2026-04-04 00:00 |
18:49:24.27 |
-45:43:47.1 |
HIP 92345 |
2.93 |
| 2026-04-04 12:00 |
18:49:24.86 |
-45:44:11.0 |
HIP 92345 |
2.70 |
| 2026-04-05 00:00 |
18:49:25.38 |
-45:44:35.0 |
HIP 92345 |
2.49 |
| 2026-04-05 12:00 |
18:49:25.85 |
-45:44:59.0 |
HIP 92345 |
2.34 |
| 2026-04-06 00:00 |
18:49:26.25 |
-45:45:23.0 |
HIP 92345 |
2.24 |
| 2026-04-06 12:00 |
18:49:26.59 |
-45:45:47.1 |
HIP 92345 |
2.20 |
| 2026-04-07 00:00 |
18:49:26.88 |
-45:46:11.3 |
HIP 92345 |
2.22 |
| 2026-04-07 12:00 |
18:49:27.10 |
-45:46:35.4 |
HIP 92367 |
2.02 |
| 2026-04-08 00:00 |
18:49:27.26 |
-45:46:59.7 |
HIP 92367 |
1.62 |
| 2026-04-08 12:00 |
18:49:27.37 |
-45:47:23.9 |
HIP 92367 |
1.22 |
| 2026-04-09 00:00 |
18:49:27.41 |
-45:47:48.2 |
HIP 92367 |
0.81 |
| 2026-04-09 12:00 |
18:49:27.39 |
-45:48:12.5 |
HIP 92367 |
0.41 |
| 2026-04-10 00:00 |
18:49:27.31 |
-45:48:36.9 |
HIP 92367 |
0.01 |
| 2026-04-10 12:00 |
18:49:27.17 |
-45:49:01.2 |
HIP 92367 |
0.41 |
| 2026-04-11 00:00 |
18:49:26.97 |
-45:49:25.6 |
HIP 92367 |
0.81 |
| 2026-04-11 12:00 |
18:49:26.71 |
-45:49:50.0 |
HIP 92367 |
1.22 |
| 2026-04-12 00:00 |
18:49:26.39 |
-45:50:14.5 |
HIP 92367 |
1.63 |
| 2026-04-12 12:00 |
18:49:26.01 |
-45:50:38.9 |
HIP 92367 |
2.05 |
| 2026-04-13 00:00 |
18:49:25.57 |
-45:51:03.4 |
HIP 92367 |
2.46 |
| 2026-04-13 12:00 |
18:49:25.07 |
-45:51:27.9 |
HIP 92367 |
2.88 |
| 2026-04-14 00:00 |
18:49:24.51 |
-45:51:52.3 |
HIP 92367 |
3.29 |
| 2026-04-14 12:00 |
18:49:23.89 |
-45:52:16.8 |
HIP 92367 |
3.71 |
| 2026-04-15 00:00 |
18:49:23.21 |
-45:52:41.3 |
HIP 92367 |
4.14 |
| 2026-04-15 12:00 |
18:49:22.47 |
-45:53:05.8 |
HIP 92367 |
4.56 |
| 2026-04-16 00:00 |
18:49:21.67 |
-45:53:30.4 |
HIP 92367 |
4.99 |