C/2012 X1 (LINEAR)
| Parameter |
Value |
| Designation |
C/2012 X1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2014-02-21T15:12:12.525120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:29Z |
| Obs used |
2560 |
| NEO |
- |
| M1 |
5.500 |
| K1 |
14.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-12-18.0000000 |
| e |
0.98957208 |
| q (au) |
1.598910 |
| a (au) |
153.329748 |
| i (deg) |
44.367326 |
| Ω (om, deg) |
113.146428 |
| ω (w, deg) |
132.113677 |
| M (ma, deg) |
359.965929 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.002 + 5.459\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.002 |
| n |
5.459 |
| gf |
0.997 |
| gb |
-0.669 |
| k |
0.934 |
| 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 |
| 2012-12-08 |
2013-11-20 |
+5.9604 |
-3.753 |
| 2013-11-20 |
2014-02-20 |
+6.1649 |
-2.791 |
| 2014-02-22 |
2015-12-09 |
+1.6254 |
-2.093 |
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 |
03:28:49.24 |
-25:04:43.9 |
HIP 16225 |
11.34 |
| 2026-02-03 12:00 |
03:28:48.65 |
-25:03:58.9 |
HIP 16225 |
10.64 |
| 2026-02-04 00:00 |
03:28:48.10 |
-25:03:13.7 |
HIP 16225 |
9.96 |
| 2026-02-04 12:00 |
03:28:47.59 |
-25:02:28.4 |
HIP 16225 |
9.28 |
| 2026-02-05 00:00 |
03:28:47.12 |
-25:01:42.9 |
HIP 16225 |
8.61 |
| 2026-02-05 12:00 |
03:28:46.69 |
-25:00:57.4 |
HIP 16225 |
7.95 |
| 2026-02-06 00:00 |
03:28:46.31 |
-25:00:11.6 |
HIP 16225 |
7.30 |
| 2026-02-06 12:00 |
03:28:45.96 |
-24:59:25.8 |
HIP 16225 |
6.68 |
| 2026-02-07 00:00 |
03:28:45.66 |
-24:58:39.8 |
HIP 16225 |
6.08 |
| 2026-02-07 12:00 |
03:28:45.39 |
-24:57:53.8 |
HIP 16225 |
5.51 |
| 2026-02-08 00:00 |
03:28:45.17 |
-24:57:07.6 |
HIP 16225 |
4.99 |
| 2026-02-08 12:00 |
03:28:44.99 |
-24:56:21.2 |
HIP 16225 |
4.54 |
| 2026-02-09 00:00 |
03:28:44.84 |
-24:55:34.8 |
HIP 16225 |
4.17 |
| 2026-02-09 12:00 |
03:28:44.74 |
-24:54:48.3 |
HIP 16225 |
3.91 |
| 2026-02-10 00:00 |
03:28:44.68 |
-24:54:01.7 |
HIP 16225 |
3.78 |
| 2026-02-10 12:00 |
03:28:44.66 |
-24:53:14.9 |
HIP 16225 |
3.81 |
| 2026-02-11 00:00 |
03:28:44.68 |
-24:52:28.1 |
HIP 16225 |
3.98 |
| 2026-02-11 12:00 |
03:28:44.74 |
-24:51:41.2 |
HIP 16225 |
4.28 |
| 2026-02-12 00:00 |
03:28:44.84 |
-24:50:54.2 |
HIP 16225 |
4.69 |
| 2026-02-12 12:00 |
03:28:44.99 |
-24:50:07.1 |
HIP 16225 |
5.18 |
| 2026-02-13 00:00 |
03:28:45.17 |
-24:49:20.0 |
HIP 16225 |
5.73 |
| 2026-02-13 12:00 |
03:28:45.39 |
-24:48:32.7 |
HIP 16225 |
6.32 |
| 2026-02-14 00:00 |
03:28:45.65 |
-24:47:45.4 |
HIP 16225 |
6.95 |
| 2026-02-14 12:00 |
03:28:45.96 |
-24:46:58.0 |
HIP 16225 |
7.61 |
| 2026-02-15 00:00 |
03:28:46.30 |
-24:46:10.5 |
HIP 16225 |
8.29 |
| 2026-02-15 12:00 |
03:28:46.69 |
-24:45:23.0 |
HIP 16225 |
8.98 |
| 2026-02-16 00:00 |
03:28:47.11 |
-24:44:35.5 |
HIP 16225 |
9.69 |
| 2026-02-16 12:00 |
03:28:47.58 |
-24:43:47.8 |
HIP 16225 |
10.41 |
| 2026-02-17 00:00 |
03:28:48.08 |
-24:43:00.1 |
HIP 16225 |
11.14 |
| 2026-02-17 12:00 |
03:28:48.62 |
-24:42:12.4 |
HIP 16225 |
11.88 |
| 2026-02-18 00:00 |
03:28:49.21 |
-24:41:24.6 |
HIP 16225 |
12.63 |
| 2026-02-18 12:00 |
03:28:49.83 |
-24:40:36.8 |
HIP 16225 |
13.38 |
| 2026-02-19 00:00 |
03:28:50.50 |
-24:39:48.9 |
HIP 16225 |
14.13 |
| 2026-02-19 12:00 |
03:28:51.20 |
-24:39:01.0 |
HIP 16225 |
14.89 |
| 2026-02-20 00:00 |
03:28:51.95 |
-24:38:13.1 |
HIP 16225 |
15.66 |
| 2026-02-20 12:00 |
03:28:52.73 |
-24:37:25.2 |
HIP 16225 |
16.43 |
| 2026-02-21 00:00 |
03:28:53.55 |
-24:36:37.2 |
HIP 16225 |
17.20 |
| 2026-02-21 12:00 |
03:28:54.42 |
-24:35:49.2 |
HIP 16225 |
17.98 |
| 2026-02-22 00:00 |
03:28:55.32 |
-24:35:01.2 |
HIP 16225 |
18.76 |
| 2026-02-22 12:00 |
03:28:56.26 |
-24:34:13.2 |
HIP 16225 |
19.55 |
| 2026-02-23 00:00 |
03:28:57.24 |
-24:33:25.2 |
HIP 16225 |
20.33 |
| 2026-02-23 12:00 |
03:28:58.25 |
-24:32:37.1 |
HIP 16225 |
21.13 |
| 2026-02-24 00:00 |
03:28:59.31 |
-24:31:49.1 |
HIP 16225 |
21.92 |