| Parameter |
Value |
| Designation |
C/2012 X2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-03-31T07:31:18.105600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:29Z |
| Obs used |
186 |
| NEO |
- |
| M1 |
12.600 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-05-10.0000000 |
| e |
0.77049741 |
| q (au) |
4.748158 |
| a (au) |
20.688908 |
| i (deg) |
34.123911 |
| Ω (om, deg) |
271.023294 |
| ω (w, deg) |
215.631135 |
| M (ma, deg) |
0.415663 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.861 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.861 |
| n |
2.000 |
| gf |
0.970 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.954 |
| 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 |
| 2012-01-11 |
2013-03-14 |
+4.8190 |
-2.842 |
| 2013-03-31 |
2014-04-24 |
-8.5263 |
+5.540 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
18:10:51.35 |
-24:13:24.4 |
HIP 89043 |
13.99 |
| 2026-03-26 12:00 |
18:10:51.77 |
-24:13:19.3 |
HIP 89043 |
14.10 |
| 2026-03-27 00:00 |
18:10:52.13 |
-24:13:14.2 |
HIP 89043 |
14.21 |
| 2026-03-27 12:00 |
18:10:52.45 |
-24:13:09.1 |
HIP 89043 |
14.32 |
| 2026-03-28 00:00 |
18:10:52.71 |
-24:13:04.0 |
HIP 89043 |
14.42 |
| 2026-03-28 12:00 |
18:10:52.93 |
-24:12:58.9 |
HIP 89043 |
14.52 |
| 2026-03-29 00:00 |
18:10:53.09 |
-24:12:53.8 |
HIP 89043 |
14.61 |
| 2026-03-29 12:00 |
18:10:53.20 |
-24:12:48.7 |
HIP 89043 |
14.70 |
| 2026-03-30 00:00 |
18:10:53.26 |
-24:12:43.6 |
HIP 89043 |
14.78 |
| 2026-03-30 12:00 |
18:10:53.26 |
-24:12:38.6 |
HIP 89043 |
14.86 |
| 2026-03-31 00:00 |
18:10:53.22 |
-24:12:33.5 |
HIP 89043 |
14.93 |
| 2026-03-31 12:00 |
18:10:53.12 |
-24:12:28.5 |
HIP 89043 |
15.00 |
| 2026-04-01 00:00 |
18:10:52.98 |
-24:12:23.5 |
HIP 89043 |
15.07 |
| 2026-04-01 12:00 |
18:10:52.78 |
-24:12:18.4 |
HIP 89043 |
15.12 |
| 2026-04-02 00:00 |
18:10:52.53 |
-24:12:13.4 |
HIP 89043 |
15.18 |
| 2026-04-02 12:00 |
18:10:52.23 |
-24:12:08.4 |
HIP 89043 |
15.23 |
| 2026-04-03 00:00 |
18:10:51.88 |
-24:12:03.4 |
HIP 89043 |
15.28 |
| 2026-04-03 12:00 |
18:10:51.47 |
-24:11:58.4 |
HIP 89043 |
15.32 |
| 2026-04-04 00:00 |
18:10:51.02 |
-24:11:53.4 |
HIP 89043 |
15.36 |
| 2026-04-04 12:00 |
18:10:50.52 |
-24:11:48.4 |
HIP 89043 |
15.39 |
| 2026-04-05 00:00 |
18:10:49.96 |
-24:11:43.5 |
HIP 89043 |
15.43 |
| 2026-04-05 12:00 |
18:10:49.35 |
-24:11:38.5 |
HIP 89043 |
15.46 |
| 2026-04-06 00:00 |
18:10:48.69 |
-24:11:33.5 |
HIP 89043 |
15.49 |
| 2026-04-06 12:00 |
18:10:47.98 |
-24:11:28.6 |
HIP 89043 |
15.51 |
| 2026-04-07 00:00 |
18:10:47.22 |
-24:11:23.7 |
HIP 89043 |
15.54 |
| 2026-04-07 12:00 |
18:10:46.41 |
-24:11:18.7 |
HIP 89043 |
15.56 |
| 2026-04-08 00:00 |
18:10:45.55 |
-24:11:13.8 |
HIP 89043 |
15.58 |
| 2026-04-08 12:00 |
18:10:44.64 |
-24:11:08.9 |
HIP 89043 |
15.61 |
| 2026-04-09 00:00 |
18:10:43.68 |
-24:11:03.9 |
HIP 89043 |
15.63 |
| 2026-04-09 12:00 |
18:10:42.66 |
-24:10:59.0 |
HIP 89043 |
15.65 |
| 2026-04-10 00:00 |
18:10:41.60 |
-24:10:54.1 |
HIP 89043 |
15.68 |
| 2026-04-10 12:00 |
18:10:40.49 |
-24:10:49.2 |
HIP 89043 |
15.70 |
| 2026-04-11 00:00 |
18:10:39.32 |
-24:10:44.3 |
HIP 89043 |
15.73 |
| 2026-04-11 12:00 |
18:10:38.11 |
-24:10:39.5 |
HIP 89043 |
15.76 |
| 2026-04-12 00:00 |
18:10:36.84 |
-24:10:34.6 |
HIP 89043 |
15.80 |
| 2026-04-12 12:00 |
18:10:35.53 |
-24:10:29.7 |
HIP 89043 |
15.84 |
| 2026-04-13 00:00 |
18:10:34.16 |
-24:10:24.8 |
HIP 89043 |
15.88 |
| 2026-04-13 12:00 |
18:10:32.75 |
-24:10:20.0 |
HIP 89043 |
15.93 |
| 2026-04-14 00:00 |
18:10:31.28 |
-24:10:15.1 |
HIP 89043 |
15.99 |
| 2026-04-14 12:00 |
18:10:29.77 |
-24:10:10.2 |
HIP 89043 |
16.05 |
| 2026-04-15 00:00 |
18:10:28.20 |
-24:10:05.4 |
HIP 89043 |
16.11 |
| 2026-04-15 12:00 |
18:10:26.59 |
-24:10:00.5 |
HIP 89043 |
16.19 |
| 2026-04-16 00:00 |
18:10:24.93 |
-24:09:55.7 |
HIP 89043 |
16.28 |