| Parameter |
Value |
| Designation |
C/2013 X1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-04-20T17:29:19.973760Z |
| Orbit solution date (soln_date, UTC) |
2022-10-25T15:34:16Z |
| Obs used |
539 |
| NEO |
- |
| M1 |
10.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-12-20.0000000 |
| e |
1.00102603 |
| q (au) |
1.314236 |
| a (au) |
-1280.894658 |
| i (deg) |
163.231932 |
| Ω (om, deg) |
130.954864 |
| ω (w, deg) |
164.460665 |
| M (ma, deg) |
-0.002639 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.099 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.099 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
8.071 |
| 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 |
| 2013-10-17 |
2015-12-16 |
-0.6279 |
-0.078 |
| 2015-12-16 |
2016-01-10 |
+25.7145 |
-8.967 |
| 2016-01-10 |
2016-04-20 |
+10.9709 |
-4.036 |
| 2016-04-22 |
2018-01-29 |
+6.2799 |
-3.384 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
11:12:53.72 |
-06:24:46.5 |
HIP 54635 |
32.99 |
| 2026-09-20 12:00 |
11:12:57.52 |
-06:25:11.5 |
HIP 54635 |
34.02 |
| 2026-09-21 00:00 |
11:13:01.32 |
-06:25:36.5 |
HIP 54635 |
35.05 |
| 2026-09-21 12:00 |
11:13:05.10 |
-06:26:01.6 |
HIP 54635 |
36.08 |
| 2026-09-22 00:00 |
11:13:08.88 |
-06:26:26.8 |
HIP 54635 |
37.10 |
| 2026-09-22 12:00 |
11:13:12.65 |
-06:26:52.0 |
HIP 54635 |
38.13 |
| 2026-09-23 00:00 |
11:13:16.42 |
-06:27:17.3 |
HIP 54635 |
39.15 |
| 2026-09-23 12:00 |
11:13:20.17 |
-06:27:42.6 |
HIP 54635 |
40.17 |
| 2026-09-24 00:00 |
11:13:23.92 |
-06:28:08.0 |
HIP 54635 |
41.20 |
| 2026-09-24 12:00 |
11:13:27.66 |
-06:28:33.5 |
HIP 54635 |
42.22 |
| 2026-09-25 00:00 |
11:13:31.39 |
-06:28:59.0 |
HIP 54635 |
43.23 |
| 2026-09-25 12:00 |
11:13:35.12 |
-06:29:24.5 |
HIP 54635 |
44.25 |
| 2026-09-26 00:00 |
11:13:38.83 |
-06:29:50.1 |
HIP 54635 |
45.27 |
| 2026-09-26 12:00 |
11:13:42.54 |
-06:30:15.8 |
HIP 54635 |
46.28 |
| 2026-09-27 00:00 |
11:13:46.23 |
-06:30:41.5 |
HIP 54791 |
46.27 |
| 2026-09-27 12:00 |
11:13:49.92 |
-06:31:07.3 |
HIP 54791 |
46.08 |
| 2026-09-28 00:00 |
11:13:53.59 |
-06:31:33.1 |
HIP 54791 |
45.91 |
| 2026-09-28 12:00 |
11:13:57.26 |
-06:31:58.9 |
HIP 54791 |
45.77 |
| 2026-09-29 00:00 |
11:14:00.91 |
-06:32:24.8 |
HIP 54791 |
45.64 |
| 2026-09-29 12:00 |
11:14:04.55 |
-06:32:50.7 |
HIP 54791 |
45.53 |
| 2026-09-30 00:00 |
11:14:08.19 |
-06:33:16.7 |
HIP 54791 |
45.45 |
| 2026-09-30 12:00 |
11:14:11.81 |
-06:33:42.7 |
HIP 54791 |
45.38 |
| 2026-10-01 00:00 |
11:14:15.42 |
-06:34:08.7 |
HIP 54791 |
45.33 |
| 2026-10-01 12:00 |
11:14:19.02 |
-06:34:34.8 |
HIP 55062 |
45.11 |
| 2026-10-02 00:00 |
11:14:22.60 |
-06:35:00.9 |
HIP 55062 |
44.19 |
| 2026-10-02 12:00 |
11:14:26.18 |
-06:35:27.0 |
HIP 55062 |
43.28 |
| 2026-10-03 00:00 |
11:14:29.74 |
-06:35:53.2 |
HIP 55062 |
42.38 |
| 2026-10-03 12:00 |
11:14:33.29 |
-06:36:19.3 |
HIP 55062 |
41.48 |
| 2026-10-04 00:00 |
11:14:36.82 |
-06:36:45.5 |
HIP 55062 |
40.59 |
| 2026-10-04 12:00 |
11:14:40.34 |
-06:37:11.8 |
HIP 55062 |
39.70 |
| 2026-10-05 00:00 |
11:14:43.85 |
-06:37:38.0 |
HIP 55062 |
38.82 |
| 2026-10-05 12:00 |
11:14:47.35 |
-06:38:04.3 |
HIP 55062 |
37.95 |
| 2026-10-06 00:00 |
11:14:50.83 |
-06:38:30.5 |
HIP 55062 |
37.08 |
| 2026-10-06 12:00 |
11:14:54.30 |
-06:38:56.8 |
HIP 55062 |
36.22 |
| 2026-10-07 00:00 |
11:14:57.75 |
-06:39:23.1 |
HIP 55062 |
35.36 |
| 2026-10-07 12:00 |
11:15:01.18 |
-06:39:49.4 |
HIP 55062 |
34.52 |
| 2026-10-08 00:00 |
11:15:04.61 |
-06:40:15.7 |
HIP 55062 |
33.68 |
| 2026-10-08 12:00 |
11:15:08.01 |
-06:40:42.1 |
HIP 55062 |
32.85 |
| 2026-10-09 00:00 |
11:15:11.40 |
-06:41:08.4 |
HIP 55062 |
32.03 |
| 2026-10-09 12:00 |
11:15:14.78 |
-06:41:34.7 |
HIP 55062 |
31.22 |
| 2026-10-10 00:00 |
11:15:18.13 |
-06:42:01.0 |
HIP 55062 |
30.42 |
| 2026-10-10 12:00 |
11:15:21.48 |
-06:42:27.4 |
HIP 55062 |
29.63 |
| 2026-10-11 00:00 |
11:15:24.80 |
-06:42:53.7 |
HIP 55062 |
28.85 |