C/2013 U2 (Holvorcem)
| Parameter |
Value |
| Designation |
C/2013 U2 (Holvorcem) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2014-10-25T20:53:27.847680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:42Z |
| Obs used |
471 |
| NEO |
- |
| M1 |
6.900 |
| K1 |
11.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2014-11-05.0000000 |
| e |
0.99429888 |
| q (au) |
5.116737 |
| a (au) |
897.497310 |
| i (deg) |
43.094095 |
| Ω (om, deg) |
7.001119 |
| ω (w, deg) |
107.375509 |
| M (ma, deg) |
0.000371 |
Magnitude
Scatter + Global Linear
$$
M_a = (2.650 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
2.650 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.503 |
| k |
1.000 |
| 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 |
| 2013-10-23 |
2014-10-24 |
+10.6160 |
-7.950 |
| 2014-11-29 |
2016-03-11 |
+5.6262 |
-4.008 |
| 2016-03-11 |
2017-03-27 |
+0.3891 |
-0.346 |
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 |
14:37:22.55 |
-50:25:08.1 |
HIP 71521 |
20.15 |
| 2026-02-03 12:00 |
14:37:22.91 |
-50:25:57.6 |
HIP 71521 |
20.96 |
| 2026-02-04 00:00 |
14:37:23.21 |
-50:26:46.9 |
HIP 71521 |
21.77 |
| 2026-02-04 12:00 |
14:37:23.44 |
-50:27:36.1 |
HIP 71521 |
22.58 |
| 2026-02-05 00:00 |
14:37:23.61 |
-50:28:25.1 |
HIP 71578 |
22.89 |
| 2026-02-05 12:00 |
14:37:23.71 |
-50:29:13.9 |
HIP 71578 |
22.14 |
| 2026-02-06 00:00 |
14:37:23.75 |
-50:30:02.5 |
HIP 71578 |
21.39 |
| 2026-02-06 12:00 |
14:37:23.72 |
-50:30:51.0 |
HIP 71578 |
20.66 |
| 2026-02-07 00:00 |
14:37:23.63 |
-50:31:39.3 |
HIP 71578 |
19.93 |
| 2026-02-07 12:00 |
14:37:23.48 |
-50:32:27.4 |
HIP 71578 |
19.23 |
| 2026-02-08 00:00 |
14:37:23.26 |
-50:33:15.4 |
HIP 71578 |
18.53 |
| 2026-02-08 12:00 |
14:37:22.97 |
-50:34:03.1 |
HIP 71578 |
17.86 |
| 2026-02-09 00:00 |
14:37:22.62 |
-50:34:50.7 |
HIP 71578 |
17.20 |
| 2026-02-09 12:00 |
14:37:22.21 |
-50:35:38.1 |
HIP 71578 |
16.56 |
| 2026-02-10 00:00 |
14:37:21.73 |
-50:36:25.2 |
HIP 71578 |
15.95 |
| 2026-02-10 12:00 |
14:37:21.18 |
-50:37:12.2 |
HIP 71578 |
15.36 |
| 2026-02-11 00:00 |
14:37:20.57 |
-50:37:59.0 |
HIP 71578 |
14.80 |
| 2026-02-11 12:00 |
14:37:19.90 |
-50:38:45.5 |
HIP 71578 |
14.26 |
| 2026-02-12 00:00 |
14:37:19.16 |
-50:39:31.9 |
HIP 71578 |
13.76 |
| 2026-02-12 12:00 |
14:37:18.36 |
-50:40:18.0 |
HIP 71578 |
13.30 |
| 2026-02-13 00:00 |
14:37:17.49 |
-50:41:03.9 |
HIP 71578 |
12.88 |
| 2026-02-13 12:00 |
14:37:16.55 |
-50:41:49.6 |
HIP 71578 |
12.50 |
| 2026-02-14 00:00 |
14:37:15.56 |
-50:42:35.1 |
HIP 71578 |
12.18 |
| 2026-02-14 12:00 |
14:37:14.49 |
-50:43:20.3 |
HIP 71578 |
11.90 |
| 2026-02-15 00:00 |
14:37:13.36 |
-50:44:05.4 |
HIP 71578 |
11.68 |
| 2026-02-15 12:00 |
14:37:12.17 |
-50:44:50.1 |
HIP 71578 |
11.52 |
| 2026-02-16 00:00 |
14:37:10.91 |
-50:45:34.7 |
HIP 71578 |
11.42 |
| 2026-02-16 12:00 |
14:37:09.59 |
-50:46:19.0 |
HIP 71578 |
11.38 |
| 2026-02-17 00:00 |
14:37:08.20 |
-50:47:03.1 |
HIP 71578 |
11.40 |
| 2026-02-17 12:00 |
14:37:06.75 |
-50:47:46.9 |
HIP 71578 |
11.48 |
| 2026-02-18 00:00 |
14:37:05.24 |
-50:48:30.5 |
HIP 71578 |
11.63 |
| 2026-02-18 12:00 |
14:37:03.66 |
-50:49:13.8 |
HIP 71578 |
11.83 |
| 2026-02-19 00:00 |
14:37:02.01 |
-50:49:56.8 |
HIP 71578 |
12.09 |
| 2026-02-19 12:00 |
14:37:00.30 |
-50:50:39.6 |
HIP 71578 |
12.40 |
| 2026-02-20 00:00 |
14:36:58.53 |
-50:51:22.2 |
HIP 71578 |
12.76 |
| 2026-02-20 12:00 |
14:36:56.69 |
-50:52:04.4 |
HIP 71578 |
13.16 |
| 2026-02-21 00:00 |
14:36:54.80 |
-50:52:46.4 |
HIP 71578 |
13.60 |
| 2026-02-21 12:00 |
14:36:52.83 |
-50:53:28.2 |
HIP 71578 |
14.07 |
| 2026-02-22 00:00 |
14:36:50.81 |
-50:54:09.6 |
HIP 71578 |
14.58 |
| 2026-02-22 12:00 |
14:36:48.72 |
-50:54:50.8 |
HIP 71578 |
15.11 |
| 2026-02-23 00:00 |
14:36:46.56 |
-50:55:31.7 |
HIP 71578 |
15.68 |
| 2026-02-23 12:00 |
14:36:44.35 |
-50:56:12.3 |
HIP 71578 |
16.26 |
| 2026-02-24 00:00 |
14:36:42.07 |
-50:56:52.6 |
HIP 71578 |
16.87 |