C/2012 L1 (LINEAR)
| Parameter |
Value |
| Designation |
C/2012 L1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2012-12-25T09:55:40.889280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:10Z |
| Obs used |
1489 |
| NEO |
- |
| M1 |
11.800 |
| K1 |
8.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-11-20.0000000 |
| e |
0.99705290 |
| q (au) |
2.262410 |
| a (au) |
767.674452 |
| i (deg) |
87.219166 |
| Ω (om, deg) |
271.766875 |
| ω (w, deg) |
140.289327 |
| M (ma, deg) |
359.998359 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.971 + 4.294\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.971 |
| n |
4.294 |
| gf |
0.998 |
| gb |
-0.847 |
| k |
0.800 |
| 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 |
| 2012-06-01 |
2012-09-11 |
+7.1051 |
-3.451 |
| 2012-09-11 |
2012-12-24 |
-1.1140 |
-0.355 |
| 2012-12-26 |
2013-04-13 |
+11.0434 |
-3.990 |
| 2013-04-13 |
2013-07-08 |
-37.4473 |
+16.045 |
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 |
06:40:25.18 |
-86:01:17.4 |
HIP 32458 |
17.75 |
| 2026-02-03 12:00 |
06:39:37.32 |
-86:00:49.7 |
HIP 32458 |
17.67 |
| 2026-02-04 00:00 |
06:38:49.95 |
-86:00:21.4 |
HIP 32458 |
17.62 |
| 2026-02-04 12:00 |
06:38:03.06 |
-85:59:52.5 |
HIP 32458 |
17.62 |
| 2026-02-05 00:00 |
06:37:16.66 |
-85:59:23.0 |
HIP 32458 |
17.66 |
| 2026-02-05 12:00 |
06:36:30.76 |
-85:58:53.0 |
HIP 32458 |
17.75 |
| 2026-02-06 00:00 |
06:35:45.36 |
-85:58:22.4 |
HIP 32458 |
17.87 |
| 2026-02-06 12:00 |
06:35:00.47 |
-85:57:51.3 |
HIP 32458 |
18.03 |
| 2026-02-07 00:00 |
06:34:16.08 |
-85:57:19.5 |
HIP 32458 |
18.24 |
| 2026-02-07 12:00 |
06:33:32.22 |
-85:56:47.3 |
HIP 32458 |
18.48 |
| 2026-02-08 00:00 |
06:32:48.88 |
-85:56:14.5 |
HIP 32458 |
18.75 |
| 2026-02-08 12:00 |
06:32:06.06 |
-85:55:41.2 |
HIP 32458 |
19.06 |
| 2026-02-09 00:00 |
06:31:23.77 |
-85:55:07.3 |
HIP 32458 |
19.40 |
| 2026-02-09 12:00 |
06:30:42.02 |
-85:54:33.0 |
HIP 32458 |
19.78 |
| 2026-02-10 00:00 |
06:30:00.80 |
-85:53:58.1 |
HIP 32458 |
20.18 |
| 2026-02-10 12:00 |
06:29:20.12 |
-85:53:22.7 |
HIP 32458 |
20.61 |
| 2026-02-11 00:00 |
06:28:39.98 |
-85:52:46.8 |
HIP 32458 |
21.06 |
| 2026-02-11 12:00 |
06:28:00.39 |
-85:52:10.5 |
HIP 32458 |
21.54 |
| 2026-02-12 00:00 |
06:27:21.35 |
-85:51:33.6 |
HIP 32458 |
22.03 |
| 2026-02-12 12:00 |
06:26:42.86 |
-85:50:56.3 |
HIP 32458 |
22.55 |
| 2026-02-13 00:00 |
06:26:04.92 |
-85:50:18.5 |
HIP 32458 |
23.09 |
| 2026-02-13 12:00 |
06:25:27.54 |
-85:49:40.3 |
HIP 32458 |
23.64 |
| 2026-02-14 00:00 |
06:24:50.71 |
-85:49:01.6 |
HIP 32458 |
24.21 |
| 2026-02-14 12:00 |
06:24:14.45 |
-85:48:22.4 |
HIP 32458 |
24.80 |
| 2026-02-15 00:00 |
06:23:38.74 |
-85:47:42.8 |
HIP 32458 |
25.39 |
| 2026-02-15 12:00 |
06:23:03.60 |
-85:47:02.8 |
HIP 32458 |
26.00 |
| 2026-02-16 00:00 |
06:22:29.02 |
-85:46:22.4 |
HIP 32458 |
26.62 |
| 2026-02-16 12:00 |
06:21:55.00 |
-85:45:41.5 |
HIP 32458 |
27.26 |
| 2026-02-17 00:00 |
06:21:21.55 |
-85:45:00.2 |
HIP 32458 |
27.90 |
| 2026-02-17 12:00 |
06:20:48.66 |
-85:44:18.6 |
HIP 32458 |
28.55 |
| 2026-02-18 00:00 |
06:20:16.34 |
-85:43:36.5 |
HIP 32458 |
29.21 |
| 2026-02-18 12:00 |
06:19:44.59 |
-85:42:54.1 |
HIP 32458 |
29.87 |
| 2026-02-19 00:00 |
06:19:13.40 |
-85:42:11.2 |
HIP 32458 |
30.54 |
| 2026-02-19 12:00 |
06:18:42.77 |
-85:41:28.1 |
HIP 29830 |
30.44 |
| 2026-02-20 00:00 |
06:18:12.72 |
-85:40:44.5 |
HIP 29830 |
29.68 |
| 2026-02-20 12:00 |
06:17:43.22 |
-85:40:00.6 |
HIP 29830 |
28.92 |
| 2026-02-21 00:00 |
06:17:14.30 |
-85:39:16.3 |
HIP 29830 |
28.17 |
| 2026-02-21 12:00 |
06:16:45.93 |
-85:38:31.7 |
HIP 29830 |
27.42 |
| 2026-02-22 00:00 |
06:16:18.13 |
-85:37:46.8 |
HIP 29830 |
26.68 |
| 2026-02-22 12:00 |
06:15:50.88 |
-85:37:01.6 |
HIP 29830 |
25.95 |
| 2026-02-23 00:00 |
06:15:24.20 |
-85:36:16.0 |
HIP 29830 |
25.22 |
| 2026-02-23 12:00 |
06:14:58.07 |
-85:35:30.1 |
HIP 29830 |
24.50 |
| 2026-02-24 00:00 |
06:14:32.50 |
-85:34:43.9 |
HIP 29830 |
23.79 |