| 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) |
| 2026-05-12 00:00 |
18:47:21.27 |
-46:13:45.8 |
HIP 92169 |
14.91 |
| 2026-05-12 12:00 |
18:47:17.54 |
-46:14:06.9 |
HIP 92169 |
15.15 |
| 2026-05-13 00:00 |
18:47:13.77 |
-46:14:27.9 |
HIP 92169 |
15.43 |
| 2026-05-13 12:00 |
18:47:09.94 |
-46:14:48.8 |
HIP 92169 |
15.74 |
| 2026-05-14 00:00 |
18:47:06.07 |
-46:15:09.5 |
HIP 92169 |
16.07 |
| 2026-05-14 12:00 |
18:47:02.14 |
-46:15:30.1 |
HIP 92169 |
16.42 |
| 2026-05-15 00:00 |
18:46:58.17 |
-46:15:50.6 |
HIP 92169 |
16.81 |
| 2026-05-15 12:00 |
18:46:54.16 |
-46:16:10.9 |
HIP 92169 |
17.21 |
| 2026-05-16 00:00 |
18:46:50.09 |
-46:16:31.1 |
HIP 92169 |
17.65 |
| 2026-05-16 12:00 |
18:46:45.98 |
-46:16:51.1 |
HIP 92169 |
18.10 |
| 2026-05-17 00:00 |
18:46:41.83 |
-46:17:11.0 |
HIP 92169 |
18.57 |
| 2026-05-17 12:00 |
18:46:37.63 |
-46:17:30.7 |
HIP 92169 |
19.07 |
| 2026-05-18 00:00 |
18:46:33.38 |
-46:17:50.3 |
HIP 92169 |
19.58 |
| 2026-05-18 12:00 |
18:46:29.09 |
-46:18:09.8 |
HIP 92050 |
19.58 |
| 2026-05-19 00:00 |
18:46:24.76 |
-46:18:29.0 |
HIP 92050 |
18.99 |
| 2026-05-19 12:00 |
18:46:20.38 |
-46:18:48.2 |
HIP 92050 |
18.42 |
| 2026-05-20 00:00 |
18:46:15.96 |
-46:19:07.1 |
HIP 92050 |
17.87 |
| 2026-05-20 12:00 |
18:46:11.49 |
-46:19:25.9 |
HIP 92050 |
17.34 |
| 2026-05-21 00:00 |
18:46:06.98 |
-46:19:44.5 |
HIP 92050 |
16.84 |
| 2026-05-21 12:00 |
18:46:02.43 |
-46:20:03.0 |
HIP 92050 |
16.36 |
| 2026-05-22 00:00 |
18:45:57.84 |
-46:20:21.3 |
HIP 92050 |
15.92 |
| 2026-05-22 12:00 |
18:45:53.21 |
-46:20:39.4 |
HIP 92050 |
15.52 |
| 2026-05-23 00:00 |
18:45:48.54 |
-46:20:57.4 |
HIP 92050 |
15.15 |
| 2026-05-23 12:00 |
18:45:43.83 |
-46:21:15.1 |
HIP 92050 |
14.83 |
| 2026-05-24 00:00 |
18:45:39.07 |
-46:21:32.7 |
HIP 92050 |
14.55 |
| 2026-05-24 12:00 |
18:45:34.28 |
-46:21:50.1 |
HIP 92050 |
14.33 |
| 2026-05-25 00:00 |
18:45:29.45 |
-46:22:07.4 |
HIP 92050 |
14.16 |
| 2026-05-25 12:00 |
18:45:24.58 |
-46:22:24.4 |
HIP 92050 |
14.04 |
| 2026-05-26 00:00 |
18:45:19.68 |
-46:22:41.3 |
HIP 92050 |
13.99 |
| 2026-05-26 12:00 |
18:45:14.73 |
-46:22:58.0 |
HIP 92050 |
14.00 |
| 2026-05-27 00:00 |
18:45:09.75 |
-46:23:14.4 |
HIP 92050 |
14.07 |
| 2026-05-27 12:00 |
18:45:04.73 |
-46:23:30.7 |
HIP 92050 |
14.21 |
| 2026-05-28 00:00 |
18:44:59.68 |
-46:23:46.8 |
HIP 92050 |
14.41 |
| 2026-05-28 12:00 |
18:44:54.59 |
-46:24:02.7 |
HIP 92050 |
14.66 |
| 2026-05-29 00:00 |
18:44:49.47 |
-46:24:18.5 |
HIP 92050 |
14.98 |
| 2026-05-29 12:00 |
18:44:44.31 |
-46:24:34.0 |
HIP 92050 |
15.34 |
| 2026-05-30 00:00 |
18:44:39.11 |
-46:24:49.3 |
HIP 92050 |
15.77 |
| 2026-05-30 12:00 |
18:44:33.89 |
-46:25:04.4 |
HIP 92050 |
16.24 |
| 2026-05-31 00:00 |
18:44:28.62 |
-46:25:19.3 |
HIP 92050 |
16.75 |
| 2026-05-31 12:00 |
18:44:23.33 |
-46:25:34.0 |
HIP 92050 |
17.31 |
| 2026-06-01 00:00 |
18:44:18.00 |
-46:25:48.5 |
HIP 92050 |
17.91 |
| 2026-06-01 12:00 |
18:44:12.65 |
-46:26:02.8 |
HIP 92050 |
18.54 |
| 2026-06-02 00:00 |
18:44:07.26 |
-46:26:16.9 |
HIP 92050 |
19.20 |