C/2013 W2 (PANSTARRS)
| Parameter |
Value |
| Designation |
C/2013 W2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-01-05T06:10:39.014400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:43Z |
| Obs used |
179 |
| NEO |
- |
| M1 |
6.900 |
| K1 |
13.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-01-20.0000000 |
| e |
0.57470690 |
| q (au) |
4.444439 |
| a (au) |
10.450297 |
| i (deg) |
4.567063 |
| Ω (om, deg) |
179.842795 |
| ω (w, deg) |
307.197933 |
| M (ma, deg) |
0.430116 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.108 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.108 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.734 |
| k |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2013-11-27 |
2014-10-24 |
+27.9138 |
-19.052 |
| 2015-01-17 |
2016-05-05 |
+3.0612 |
-2.167 |
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 |
19:14:34.96 |
-17:56:44.3 |
HIP 94534 |
4.01 |
| 2026-02-03 12:00 |
19:14:43.87 |
-17:56:24.5 |
HIP 94534 |
5.65 |
| 2026-02-04 00:00 |
19:14:52.76 |
-17:56:04.7 |
HIP 94534 |
7.54 |
| 2026-02-04 12:00 |
19:15:01.62 |
-17:55:44.9 |
HIP 94534 |
9.53 |
| 2026-02-05 00:00 |
19:15:10.45 |
-17:55:25.0 |
HIP 94534 |
11.56 |
| 2026-02-05 12:00 |
19:15:19.25 |
-17:55:05.0 |
HIP 94534 |
13.62 |
| 2026-02-06 00:00 |
19:15:28.02 |
-17:54:45.0 |
HIP 94534 |
15.68 |
| 2026-02-06 12:00 |
19:15:36.76 |
-17:54:25.0 |
HIP 94544 |
17.73 |
| 2026-02-07 00:00 |
19:15:45.46 |
-17:54:05.0 |
HIP 94544 |
19.69 |
| 2026-02-07 12:00 |
19:15:54.13 |
-17:53:44.9 |
HIP 94544 |
21.67 |
| 2026-02-08 00:00 |
19:16:02.77 |
-17:53:24.7 |
HIP 94811 |
21.50 |
| 2026-02-08 12:00 |
19:16:11.38 |
-17:53:04.6 |
HIP 94811 |
19.43 |
| 2026-02-09 00:00 |
19:16:19.95 |
-17:52:44.4 |
HIP 94811 |
17.36 |
| 2026-02-09 12:00 |
19:16:28.49 |
-17:52:24.2 |
HIP 94811 |
15.30 |
| 2026-02-10 00:00 |
19:16:36.99 |
-17:52:03.9 |
HIP 94811 |
13.26 |
| 2026-02-10 12:00 |
19:16:45.46 |
-17:51:43.6 |
HIP 94811 |
11.21 |
| 2026-02-11 00:00 |
19:16:53.89 |
-17:51:23.3 |
HIP 94811 |
9.18 |
| 2026-02-11 12:00 |
19:17:02.28 |
-17:51:03.0 |
HIP 94811 |
7.16 |
| 2026-02-12 00:00 |
19:17:10.64 |
-17:50:42.6 |
HIP 94811 |
5.15 |
| 2026-02-12 12:00 |
19:17:18.96 |
-17:50:22.2 |
HIP 94811 |
3.16 |
| 2026-02-13 00:00 |
19:17:27.24 |
-17:50:01.9 |
HIP 94811 |
1.24 |
| 2026-02-13 12:00 |
19:17:35.49 |
-17:49:41.4 |
HIP 94811 |
1.03 |
| 2026-02-14 00:00 |
19:17:43.69 |
-17:49:21.0 |
HIP 94811 |
2.91 |
| 2026-02-14 12:00 |
19:17:51.86 |
-17:49:00.6 |
HIP 94811 |
4.86 |
| 2026-02-15 00:00 |
19:17:59.99 |
-17:48:40.1 |
HIP 94811 |
6.82 |
| 2026-02-15 12:00 |
19:18:08.07 |
-17:48:19.6 |
HIP 94811 |
8.77 |
| 2026-02-16 00:00 |
19:18:16.12 |
-17:47:59.1 |
HIP 94811 |
10.71 |
| 2026-02-16 12:00 |
19:18:24.12 |
-17:47:38.6 |
HIP 94811 |
12.64 |
| 2026-02-17 00:00 |
19:18:32.09 |
-17:47:18.1 |
HIP 94811 |
14.57 |
| 2026-02-17 12:00 |
19:18:40.01 |
-17:46:57.6 |
HIP 94811 |
16.48 |
| 2026-02-18 00:00 |
19:18:47.89 |
-17:46:37.1 |
HIP 94811 |
18.39 |
| 2026-02-18 12:00 |
19:18:55.73 |
-17:46:16.6 |
HIP 94811 |
20.28 |
| 2026-02-19 00:00 |
19:19:03.52 |
-17:45:56.1 |
HIP 94811 |
22.17 |
| 2026-02-19 12:00 |
19:19:11.27 |
-17:45:35.6 |
HIP 94811 |
24.04 |
| 2026-02-20 00:00 |
19:19:18.97 |
-17:45:15.0 |
HIP 94811 |
25.91 |
| 2026-02-20 12:00 |
19:19:26.63 |
-17:44:54.5 |
HIP 94811 |
27.77 |
| 2026-02-21 00:00 |
19:19:34.25 |
-17:44:34.0 |
HIP 94811 |
29.61 |
| 2026-02-21 12:00 |
19:19:41.82 |
-17:44:13.5 |
HIP 95168 |
28.99 |
| 2026-02-22 00:00 |
19:19:49.34 |
-17:43:53.0 |
HIP 95168 |
27.33 |
| 2026-02-22 12:00 |
19:19:56.82 |
-17:43:32.6 |
HIP 95168 |
25.71 |
| 2026-02-23 00:00 |
19:20:04.25 |
-17:43:12.1 |
HIP 95168 |
24.12 |
| 2026-02-23 12:00 |
19:20:11.63 |
-17:42:51.6 |
HIP 95168 |
22.58 |
| 2026-02-24 00:00 |
19:20:18.97 |
-17:42:31.2 |
HIP 95168 |
21.09 |