| 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) |
| 2026-07-29 00:00 |
14:13:10.77 |
-49:52:55.2 |
HIP 69448 |
10.94 |
| 2026-07-29 12:00 |
14:13:11.48 |
-49:52:20.8 |
HIP 69448 |
11.52 |
| 2026-07-30 00:00 |
14:13:12.24 |
-49:51:46.5 |
HIP 69448 |
12.09 |
| 2026-07-30 12:00 |
14:13:13.07 |
-49:51:12.5 |
HIP 69368 |
12.38 |
| 2026-07-31 00:00 |
14:13:13.95 |
-49:50:38.7 |
HIP 69368 |
12.68 |
| 2026-07-31 12:00 |
14:13:14.89 |
-49:50:05.0 |
HIP 69368 |
13.01 |
| 2026-08-01 00:00 |
14:13:15.88 |
-49:49:31.6 |
HIP 69368 |
13.36 |
| 2026-08-01 12:00 |
14:13:16.94 |
-49:48:58.3 |
HIP 69368 |
13.73 |
| 2026-08-02 00:00 |
14:13:18.05 |
-49:48:25.3 |
HIP 69368 |
14.13 |
| 2026-08-02 12:00 |
14:13:19.21 |
-49:47:52.4 |
HIP 69368 |
14.54 |
| 2026-08-03 00:00 |
14:13:20.44 |
-49:47:19.8 |
HIP 69368 |
14.97 |
| 2026-08-03 12:00 |
14:13:21.72 |
-49:46:47.3 |
HIP 69368 |
15.42 |
| 2026-08-04 00:00 |
14:13:23.06 |
-49:46:15.1 |
HIP 69368 |
15.88 |
| 2026-08-04 12:00 |
14:13:24.45 |
-49:45:43.1 |
HIP 69368 |
16.35 |
| 2026-08-05 00:00 |
14:13:25.90 |
-49:45:11.4 |
HIP 69368 |
16.84 |
| 2026-08-05 12:00 |
14:13:27.41 |
-49:44:39.8 |
HIP 69368 |
17.34 |
| 2026-08-06 00:00 |
14:13:28.98 |
-49:44:08.5 |
HIP 69368 |
17.85 |
| 2026-08-06 12:00 |
14:13:30.60 |
-49:43:37.4 |
HIP 69368 |
18.37 |
| 2026-08-07 00:00 |
14:13:32.27 |
-49:43:06.5 |
HIP 69368 |
18.89 |
| 2026-08-07 12:00 |
14:13:34.01 |
-49:42:35.8 |
HIP 69368 |
19.43 |
| 2026-08-08 00:00 |
14:13:35.79 |
-49:42:05.4 |
HIP 69368 |
19.97 |
| 2026-08-08 12:00 |
14:13:37.64 |
-49:41:35.2 |
HIP 69368 |
20.52 |
| 2026-08-09 00:00 |
14:13:39.54 |
-49:41:05.3 |
HIP 69368 |
21.07 |
| 2026-08-09 12:00 |
14:13:41.49 |
-49:40:35.6 |
HIP 69368 |
21.63 |
| 2026-08-10 00:00 |
14:13:43.51 |
-49:40:06.2 |
HIP 69693 |
21.73 |
| 2026-08-10 12:00 |
14:13:45.57 |
-49:39:37.0 |
HIP 69693 |
21.46 |
| 2026-08-11 00:00 |
14:13:47.69 |
-49:39:08.0 |
HIP 69693 |
21.20 |
| 2026-08-11 12:00 |
14:13:49.87 |
-49:38:39.3 |
HIP 69693 |
20.94 |
| 2026-08-12 00:00 |
14:13:52.10 |
-49:38:10.8 |
HIP 69693 |
20.68 |
| 2026-08-12 12:00 |
14:13:54.39 |
-49:37:42.6 |
HIP 69693 |
20.43 |
| 2026-08-13 00:00 |
14:13:56.73 |
-49:37:14.7 |
HIP 69693 |
20.18 |
| 2026-08-13 12:00 |
14:13:59.12 |
-49:36:47.0 |
HIP 69693 |
19.94 |
| 2026-08-14 00:00 |
14:14:01.57 |
-49:36:19.6 |
HIP 69693 |
19.70 |
| 2026-08-14 12:00 |
14:14:04.07 |
-49:35:52.5 |
HIP 69693 |
19.47 |
| 2026-08-15 00:00 |
14:14:06.63 |
-49:35:25.6 |
HIP 69693 |
19.24 |
| 2026-08-15 12:00 |
14:14:09.24 |
-49:34:59.0 |
HIP 69693 |
19.03 |
| 2026-08-16 00:00 |
14:14:11.90 |
-49:34:32.7 |
HIP 69693 |
18.82 |
| 2026-08-16 12:00 |
14:14:14.62 |
-49:34:06.6 |
HIP 69693 |
18.61 |
| 2026-08-17 00:00 |
14:14:17.39 |
-49:33:40.8 |
HIP 69693 |
18.42 |
| 2026-08-17 12:00 |
14:14:20.21 |
-49:33:15.3 |
HIP 69693 |
18.24 |
| 2026-08-18 00:00 |
14:14:23.08 |
-49:32:50.1 |
HIP 69693 |
18.06 |
| 2026-08-18 12:00 |
14:14:26.01 |
-49:32:25.1 |
HIP 69693 |
17.90 |
| 2026-08-19 00:00 |
14:14:28.99 |
-49:32:00.5 |
HIP 69693 |
17.75 |