C/2012 X1 (LINEAR)

Metadata

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

C/2012 X1 (LINEAR) · Magnitude (Full range)

Scatter + Global Linear

$$ M_a = (7.004 + 5.465\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter Value
H0 7.004
n 5.465
gf 1.000
gb -0.669
k 0.933
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 +5.9231 -3.732
2013-11-20 2014-02-20 +6.3519 -2.844
2014-02-22 2015-12-09 +1.6210 -2.089

log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)

Ephemeris

Date/Time (UTC) RA (J2000) Dec (J2000) Nearest HIP Dist from HIP (arcmin)
2026-06-01 00:00 03:40:27.50 -22:50:30.2 HIP 17350 32.89
2026-06-01 12:00 03:40:31.95 -22:50:27.3 HIP 17350 31.87
2026-06-02 00:00 03:40:36.40 -22:50:24.8 HIP 17350 30.87
2026-06-02 12:00 03:40:40.83 -22:50:22.6 HIP 17350 29.86
2026-06-03 00:00 03:40:45.26 -22:50:20.7 HIP 17350 28.86
2026-06-03 12:00 03:40:49.67 -22:50:19.3 HIP 17350 27.85
2026-06-04 00:00 03:40:54.08 -22:50:18.1 HIP 17350 26.85
2026-06-04 12:00 03:40:58.48 -22:50:17.4 HIP 17350 25.86
2026-06-05 00:00 03:41:02.87 -22:50:16.9 HIP 17350 24.86
2026-06-05 12:00 03:41:07.25 -22:50:16.9 HIP 17350 23.87
2026-06-06 00:00 03:41:11.62 -22:50:17.2 HIP 17350 22.88
2026-06-06 12:00 03:41:15.98 -22:50:17.8 HIP 17350 21.89
2026-06-07 00:00 03:41:20.32 -22:50:18.8 HIP 17350 20.91
2026-06-07 12:00 03:41:24.66 -22:50:20.1 HIP 17350 19.93
2026-06-08 00:00 03:41:28.99 -22:50:21.8 HIP 17350 18.95
2026-06-08 12:00 03:41:33.30 -22:50:23.9 HIP 17350 17.97
2026-06-09 00:00 03:41:37.60 -22:50:26.3 HIP 17350 17.00
2026-06-09 12:00 03:41:41.89 -22:50:29.0 HIP 17350 16.04
2026-06-10 00:00 03:41:46.17 -22:50:32.1 HIP 17350 15.07
2026-06-10 12:00 03:41:50.43 -22:50:35.6 HIP 17350 14.11
2026-06-11 00:00 03:41:54.69 -22:50:39.4 HIP 17350 13.16
2026-06-11 12:00 03:41:58.93 -22:50:43.5 HIP 17350 12.21
2026-06-12 00:00 03:42:03.15 -22:50:48.1 HIP 17350 11.26
2026-06-12 12:00 03:42:07.36 -22:50:52.9 HIP 17350 10.33
2026-06-13 00:00 03:42:11.56 -22:50:58.2 HIP 17350 9.40
2026-06-13 12:00 03:42:15.75 -22:51:03.7 HIP 17350 8.48
2026-06-14 00:00 03:42:19.92 -22:51:09.6 HIP 17350 7.57
2026-06-14 12:00 03:42:24.07 -22:51:15.9 HIP 17350 6.68
2026-06-15 00:00 03:42:28.21 -22:51:22.5 HIP 17350 5.81
2026-06-15 12:00 03:42:32.33 -22:51:29.5 HIP 17350 4.98
2026-06-16 00:00 03:42:36.44 -22:51:36.8 HIP 17350 4.20
2026-06-16 12:00 03:42:40.54 -22:51:44.5 HIP 17350 3.50
2026-06-17 00:00 03:42:44.61 -22:51:52.5 HIP 17350 2.94
2026-06-17 12:00 03:42:48.67 -22:52:00.9 HIP 17350 2.61
2026-06-18 00:00 03:42:52.72 -22:52:09.6 HIP 17350 2.60
2026-06-18 12:00 03:42:56.74 -22:52:18.7 HIP 17350 2.90
2026-06-19 00:00 03:43:00.75 -22:52:28.1 HIP 17350 3.43
2026-06-19 12:00 03:43:04.74 -22:52:37.9 HIP 17350 4.11
2026-06-20 00:00 03:43:08.72 -22:52:47.9 HIP 17350 4.86
2026-06-20 12:00 03:43:12.67 -22:52:58.4 HIP 17350 5.66
2026-06-21 00:00 03:43:16.61 -22:53:09.2 HIP 17350 6.49
2026-06-21 12:00 03:43:20.53 -22:53:20.3 HIP 17350 7.34
2026-06-22 00:00 03:43:24.43 -22:53:31.7 HIP 17350 8.20