| 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 |
9.998 |
| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
18:44:01.83 |
-46:26:30.7 |
HIP 92050 |
19.90 |
| 2026-06-03 00:00 |
18:43:56.38 |
-46:26:44.4 |
HIP 92050 |
20.62 |
| 2026-06-03 12:00 |
18:43:50.90 |
-46:26:57.8 |
HIP 92050 |
21.37 |
| 2026-06-04 00:00 |
18:43:45.39 |
-46:27:11.0 |
HIP 92050 |
22.14 |
| 2026-06-04 12:00 |
18:43:39.85 |
-46:27:24.0 |
HIP 92050 |
22.93 |
| 2026-06-05 00:00 |
18:43:34.28 |
-46:27:36.8 |
HIP 92050 |
23.75 |
| 2026-06-05 12:00 |
18:43:28.68 |
-46:27:49.4 |
HIP 92050 |
24.58 |
| 2026-06-06 00:00 |
18:43:23.06 |
-46:28:01.7 |
HIP 92050 |
25.42 |
| 2026-06-06 12:00 |
18:43:17.40 |
-46:28:13.8 |
HIP 92050 |
26.28 |
| 2026-06-07 00:00 |
18:43:11.72 |
-46:28:25.7 |
HIP 92050 |
27.16 |
| 2026-06-07 12:00 |
18:43:06.02 |
-46:28:37.4 |
HIP 92050 |
28.05 |
| 2026-06-08 00:00 |
18:43:00.29 |
-46:28:48.8 |
HIP 92050 |
28.95 |
| 2026-06-08 12:00 |
18:42:54.53 |
-46:29:00.0 |
HIP 92050 |
29.87 |
| 2026-06-09 00:00 |
18:42:48.75 |
-46:29:11.0 |
HIP 92050 |
30.79 |
| 2026-06-09 12:00 |
18:42:42.94 |
-46:29:21.7 |
HIP 91840 |
31.63 |
| 2026-06-10 00:00 |
18:42:37.11 |
-46:29:32.2 |
HIP 91840 |
31.72 |
| 2026-06-10 12:00 |
18:42:31.26 |
-46:29:42.4 |
HIP 91840 |
31.84 |
| 2026-06-11 00:00 |
18:42:25.39 |
-46:29:52.5 |
HIP 91840 |
32.00 |
| 2026-06-11 12:00 |
18:42:19.49 |
-46:30:02.2 |
HIP 91840 |
32.20 |
| 2026-06-12 00:00 |
18:42:13.57 |
-46:30:11.8 |
HIP 91840 |
32.44 |
| 2026-06-12 12:00 |
18:42:07.63 |
-46:30:21.1 |
HIP 91840 |
32.71 |
| 2026-06-13 00:00 |
18:42:01.67 |
-46:30:30.1 |
HIP 91840 |
33.01 |
| 2026-06-13 12:00 |
18:41:55.69 |
-46:30:38.9 |
HIP 91589 |
33.34 |
| 2026-06-14 00:00 |
18:41:49.69 |
-46:30:47.5 |
HIP 91589 |
32.84 |
| 2026-06-14 12:00 |
18:41:43.67 |
-46:30:55.8 |
HIP 91589 |
32.37 |
| 2026-06-15 00:00 |
18:41:37.64 |
-46:31:03.8 |
HIP 91589 |
31.93 |
| 2026-06-15 12:00 |
18:41:31.58 |
-46:31:11.6 |
HIP 91589 |
31.52 |
| 2026-06-16 00:00 |
18:41:25.51 |
-46:31:19.2 |
HIP 91589 |
31.14 |
| 2026-06-16 12:00 |
18:41:19.43 |
-46:31:26.5 |
HIP 91589 |
30.80 |
| 2026-06-17 00:00 |
18:41:13.32 |
-46:31:33.5 |
HIP 91589 |
30.50 |
| 2026-06-17 12:00 |
18:41:07.21 |
-46:31:40.3 |
HIP 91589 |
30.23 |
| 2026-06-18 00:00 |
18:41:01.08 |
-46:31:46.8 |
HIP 91376 |
29.30 |
| 2026-06-18 12:00 |
18:40:54.93 |
-46:31:53.1 |
HIP 91376 |
28.24 |
| 2026-06-19 00:00 |
18:40:48.77 |
-46:31:59.1 |
HIP 91376 |
27.18 |
| 2026-06-19 12:00 |
18:40:42.60 |
-46:32:04.8 |
HIP 91376 |
26.11 |
| 2026-06-20 00:00 |
18:40:36.42 |
-46:32:10.3 |
HIP 91376 |
25.04 |
| 2026-06-20 12:00 |
18:40:30.23 |
-46:32:15.6 |
HIP 91376 |
23.97 |
| 2026-06-21 00:00 |
18:40:24.03 |
-46:32:20.5 |
HIP 91376 |
22.90 |
| 2026-06-21 12:00 |
18:40:17.81 |
-46:32:25.2 |
HIP 91376 |
21.83 |
| 2026-06-22 00:00 |
18:40:11.59 |
-46:32:29.7 |
HIP 91376 |
20.76 |