| Parameter |
Value |
| Designation |
C/2013 D1 (Holvorcem) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-04-13T17:17:27.458880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:30Z |
| Obs used |
118 |
| NEO |
- |
| M1 |
13.500 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-03-26.0000000 |
| e |
0.78087861 |
| q (au) |
2.460129 |
| a (au) |
11.227243 |
| i (deg) |
10.093564 |
| Ω (om, deg) |
294.974884 |
| ω (w, deg) |
252.631501 |
| M (ma, deg) |
359.509532 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.750 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.750 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.790 |
| k |
0.800 |
| δ90 |
5.227 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
23:41:10.48 |
+07:57:43.8 |
HIP 116816 |
12.21 |
| 2026-07-29 12:00 |
23:41:07.20 |
+07:57:36.6 |
HIP 116816 |
11.50 |
| 2026-07-30 00:00 |
23:41:03.87 |
+07:57:29.0 |
HIP 116816 |
10.79 |
| 2026-07-30 12:00 |
23:41:00.51 |
+07:57:21.1 |
HIP 116816 |
10.09 |
| 2026-07-31 00:00 |
23:40:57.11 |
+07:57:12.8 |
HIP 116816 |
9.40 |
| 2026-07-31 12:00 |
23:40:53.66 |
+07:57:04.2 |
HIP 116816 |
8.74 |
| 2026-08-01 00:00 |
23:40:50.18 |
+07:56:55.3 |
HIP 116816 |
8.10 |
| 2026-08-01 12:00 |
23:40:46.66 |
+07:56:46.0 |
HIP 116816 |
7.50 |
| 2026-08-02 00:00 |
23:40:43.11 |
+07:56:36.5 |
HIP 116816 |
6.94 |
| 2026-08-02 12:00 |
23:40:39.51 |
+07:56:26.5 |
HIP 116816 |
6.46 |
| 2026-08-03 00:00 |
23:40:35.88 |
+07:56:16.3 |
HIP 116816 |
6.07 |
| 2026-08-03 12:00 |
23:40:32.21 |
+07:56:05.7 |
HIP 116816 |
5.80 |
| 2026-08-04 00:00 |
23:40:28.50 |
+07:55:54.8 |
HIP 116816 |
5.65 |
| 2026-08-04 12:00 |
23:40:24.75 |
+07:55:43.5 |
HIP 116816 |
5.66 |
| 2026-08-05 00:00 |
23:40:20.97 |
+07:55:31.9 |
HIP 116816 |
5.83 |
| 2026-08-05 12:00 |
23:40:17.15 |
+07:55:20.0 |
HIP 116816 |
6.14 |
| 2026-08-06 00:00 |
23:40:13.30 |
+07:55:07.8 |
HIP 116816 |
6.58 |
| 2026-08-06 12:00 |
23:40:09.41 |
+07:54:55.2 |
HIP 116816 |
7.13 |
| 2026-08-07 00:00 |
23:40:05.48 |
+07:54:42.3 |
HIP 116816 |
7.77 |
| 2026-08-07 12:00 |
23:40:01.52 |
+07:54:29.1 |
HIP 116816 |
8.49 |
| 2026-08-08 00:00 |
23:39:57.53 |
+07:54:15.6 |
HIP 116816 |
9.26 |
| 2026-08-08 12:00 |
23:39:53.50 |
+07:54:01.7 |
HIP 116816 |
10.09 |
| 2026-08-09 00:00 |
23:39:49.43 |
+07:53:47.5 |
HIP 116816 |
10.95 |
| 2026-08-09 12:00 |
23:39:45.33 |
+07:53:33.0 |
HIP 116816 |
11.85 |
| 2026-08-10 00:00 |
23:39:41.20 |
+07:53:18.1 |
HIP 116816 |
12.78 |
| 2026-08-10 12:00 |
23:39:37.04 |
+07:53:02.9 |
HIP 116816 |
13.73 |
| 2026-08-11 00:00 |
23:39:32.84 |
+07:52:47.4 |
HIP 116816 |
14.70 |
| 2026-08-11 12:00 |
23:39:28.61 |
+07:52:31.6 |
HIP 116816 |
15.70 |
| 2026-08-12 00:00 |
23:39:24.35 |
+07:52:15.5 |
HIP 116816 |
16.71 |
| 2026-08-12 12:00 |
23:39:20.05 |
+07:51:59.1 |
HIP 116816 |
17.74 |
| 2026-08-13 00:00 |
23:39:15.72 |
+07:51:42.3 |
HIP 116816 |
18.78 |
| 2026-08-13 12:00 |
23:39:11.37 |
+07:51:25.2 |
HIP 116816 |
19.84 |
| 2026-08-14 00:00 |
23:39:06.98 |
+07:51:07.9 |
HIP 116816 |
20.91 |
| 2026-08-14 12:00 |
23:39:02.56 |
+07:50:50.2 |
HIP 116816 |
21.99 |
| 2026-08-15 00:00 |
23:38:58.12 |
+07:50:32.2 |
HIP 116816 |
23.09 |
| 2026-08-15 12:00 |
23:38:53.64 |
+07:50:13.9 |
HIP 116816 |
24.20 |
| 2026-08-16 00:00 |
23:38:49.13 |
+07:49:55.2 |
HIP 116571 |
24.69 |
| 2026-08-16 12:00 |
23:38:44.60 |
+07:49:36.3 |
HIP 116571 |
23.56 |
| 2026-08-17 00:00 |
23:38:40.04 |
+07:49:17.1 |
HIP 116571 |
22.43 |
| 2026-08-17 12:00 |
23:38:35.45 |
+07:48:57.6 |
HIP 116550 |
21.25 |
| 2026-08-18 00:00 |
23:38:30.83 |
+07:48:37.8 |
HIP 116550 |
20.06 |
| 2026-08-18 12:00 |
23:38:26.19 |
+07:48:17.7 |
HIP 116550 |
18.86 |
| 2026-08-19 00:00 |
23:38:21.52 |
+07:47:57.3 |
HIP 116550 |
17.66 |