| Parameter |
Value |
| Designation |
C/2013 H1 (La Sagra) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-05-19T16:02:02.639040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:34Z |
| Obs used |
270 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
22.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-05-18.0000000 |
| e |
0.98542562 |
| q (au) |
2.646966 |
| a (au) |
181.617687 |
| i (deg) |
27.089519 |
| Ω (om, deg) |
84.969862 |
| ω (w, deg) |
136.581161 |
| M (ma, deg) |
359.999328 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.300 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.300 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
01:23:28.93 |
-20:16:00.5 |
HIP 6491 |
3.37 |
| 2026-07-29 12:00 |
01:23:28.24 |
-20:16:32.1 |
HIP 6491 |
2.82 |
| 2026-07-30 00:00 |
01:23:27.51 |
-20:17:03.8 |
HIP 6491 |
2.26 |
| 2026-07-30 12:00 |
01:23:26.75 |
-20:17:35.6 |
HIP 6491 |
1.70 |
| 2026-07-31 00:00 |
01:23:25.95 |
-20:18:07.5 |
HIP 6491 |
1.14 |
| 2026-07-31 12:00 |
01:23:25.12 |
-20:18:39.5 |
HIP 6491 |
0.57 |
| 2026-08-01 00:00 |
01:23:24.26 |
-20:19:11.7 |
HIP 6491 |
0.01 |
| 2026-08-01 12:00 |
01:23:23.36 |
-20:19:43.9 |
HIP 6491 |
0.58 |
| 2026-08-02 00:00 |
01:23:22.43 |
-20:20:16.2 |
HIP 6491 |
1.16 |
| 2026-08-02 12:00 |
01:23:21.47 |
-20:20:48.7 |
HIP 6491 |
1.75 |
| 2026-08-03 00:00 |
01:23:20.47 |
-20:21:21.2 |
HIP 6491 |
2.34 |
| 2026-08-03 12:00 |
01:23:19.44 |
-20:21:53.9 |
HIP 6491 |
2.93 |
| 2026-08-04 00:00 |
01:23:18.37 |
-20:22:26.6 |
HIP 6491 |
3.53 |
| 2026-08-04 12:00 |
01:23:17.28 |
-20:22:59.4 |
HIP 6491 |
4.13 |
| 2026-08-05 00:00 |
01:23:16.14 |
-20:23:32.3 |
HIP 6491 |
4.74 |
| 2026-08-05 12:00 |
01:23:14.98 |
-20:24:05.3 |
HIP 6491 |
5.36 |
| 2026-08-06 00:00 |
01:23:13.78 |
-20:24:38.4 |
HIP 6491 |
5.98 |
| 2026-08-06 12:00 |
01:23:12.55 |
-20:25:11.6 |
HIP 6491 |
6.60 |
| 2026-08-07 00:00 |
01:23:11.28 |
-20:25:44.8 |
HIP 6491 |
7.23 |
| 2026-08-07 12:00 |
01:23:09.98 |
-20:26:18.1 |
HIP 6491 |
7.86 |
| 2026-08-08 00:00 |
01:23:08.65 |
-20:26:51.5 |
HIP 6491 |
8.49 |
| 2026-08-08 12:00 |
01:23:07.29 |
-20:27:25.0 |
HIP 6491 |
9.13 |
| 2026-08-09 00:00 |
01:23:05.89 |
-20:27:58.5 |
HIP 6491 |
9.78 |
| 2026-08-09 12:00 |
01:23:04.46 |
-20:28:32.1 |
HIP 6491 |
10.43 |
| 2026-08-10 00:00 |
01:23:03.00 |
-20:29:05.7 |
HIP 6491 |
11.09 |
| 2026-08-10 12:00 |
01:23:01.50 |
-20:29:39.5 |
HIP 6491 |
11.75 |
| 2026-08-11 00:00 |
01:22:59.97 |
-20:30:13.2 |
HIP 6491 |
12.41 |
| 2026-08-11 12:00 |
01:22:58.41 |
-20:30:47.1 |
HIP 6491 |
13.08 |
| 2026-08-12 00:00 |
01:22:56.82 |
-20:31:20.9 |
HIP 6450 |
12.87 |
| 2026-08-12 12:00 |
01:22:55.19 |
-20:31:54.9 |
HIP 6450 |
12.28 |
| 2026-08-13 00:00 |
01:22:53.53 |
-20:32:28.8 |
HIP 6450 |
11.71 |
| 2026-08-13 12:00 |
01:22:51.84 |
-20:33:02.8 |
HIP 6450 |
11.14 |
| 2026-08-14 00:00 |
01:22:50.12 |
-20:33:36.9 |
HIP 6450 |
10.60 |
| 2026-08-14 12:00 |
01:22:48.36 |
-20:34:10.9 |
HIP 6450 |
10.07 |
| 2026-08-15 00:00 |
01:22:46.58 |
-20:34:45.1 |
HIP 6450 |
9.56 |
| 2026-08-15 12:00 |
01:22:44.76 |
-20:35:19.2 |
HIP 6450 |
9.08 |
| 2026-08-16 00:00 |
01:22:42.91 |
-20:35:53.4 |
HIP 6450 |
8.64 |
| 2026-08-16 12:00 |
01:22:41.03 |
-20:36:27.6 |
HIP 6450 |
8.23 |
| 2026-08-17 00:00 |
01:22:39.12 |
-20:37:01.8 |
HIP 6450 |
7.88 |
| 2026-08-17 12:00 |
01:22:37.18 |
-20:37:36.0 |
HIP 6450 |
7.58 |
| 2026-08-18 00:00 |
01:22:35.21 |
-20:38:10.2 |
HIP 6450 |
7.34 |
| 2026-08-18 12:00 |
01:22:33.21 |
-20:38:44.5 |
HIP 6450 |
7.18 |
| 2026-08-19 00:00 |
01:22:31.18 |
-20:39:18.7 |
HIP 6450 |
7.09 |