| Parameter |
Value |
| Designation |
113P/Spitaler |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-04-23T18:19:34.599360Z |
| Orbit solution date (soln_date, UTC) |
2024-04-29T13:12:26Z |
| Obs used |
879 |
| NEO |
- |
| M1 |
14.700 |
| K1 |
8.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-07-26.0000000 |
| e |
0.42451621 |
| q (au) |
2.118865 |
| a (au) |
3.681885 |
| i (deg) |
5.776267 |
| Ω (om, deg) |
14.385093 |
| ω (w, deg) |
50.026650 |
| M (ma, deg) |
13.007213 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.379 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.379 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.854 |
| k |
0.999 |
| 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 |
| 2021-06-18 |
2022-06-01 |
+1.1076 |
-0.529 |
| 2022-06-01 |
2023-04-15 |
+5.3352 |
-1.919 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
17:10:35.61 |
-27:48:07.2 |
HIP 84175 |
24.33 |
| 2026-03-26 12:00 |
17:10:37.35 |
-27:48:31.2 |
HIP 84175 |
23.99 |
| 2026-03-27 00:00 |
17:10:38.87 |
-27:48:55.0 |
HIP 84175 |
23.70 |
| 2026-03-27 12:00 |
17:10:40.17 |
-27:49:18.6 |
HIP 84175 |
23.48 |
| 2026-03-28 00:00 |
17:10:41.25 |
-27:49:41.9 |
HIP 84175 |
23.30 |
| 2026-03-28 12:00 |
17:10:42.10 |
-27:50:04.9 |
HIP 84175 |
23.18 |
| 2026-03-29 00:00 |
17:10:42.74 |
-27:50:27.7 |
HIP 84175 |
23.12 |
| 2026-03-29 12:00 |
17:10:43.16 |
-27:50:50.2 |
HIP 84175 |
23.11 |
| 2026-03-30 00:00 |
17:10:43.35 |
-27:51:12.4 |
HIP 84175 |
23.15 |
| 2026-03-30 12:00 |
17:10:43.33 |
-27:51:34.4 |
HIP 84175 |
23.25 |
| 2026-03-31 00:00 |
17:10:43.08 |
-27:51:56.0 |
HIP 84175 |
23.39 |
| 2026-03-31 12:00 |
17:10:42.61 |
-27:52:17.4 |
HIP 84175 |
23.59 |
| 2026-04-01 00:00 |
17:10:41.92 |
-27:52:38.6 |
HIP 84175 |
23.83 |
| 2026-04-01 12:00 |
17:10:41.01 |
-27:52:59.4 |
HIP 84175 |
24.13 |
| 2026-04-02 00:00 |
17:10:39.87 |
-27:53:20.0 |
HIP 84175 |
24.47 |
| 2026-04-02 12:00 |
17:10:38.51 |
-27:53:40.2 |
HIP 84175 |
24.86 |
| 2026-04-03 00:00 |
17:10:36.92 |
-27:54:00.2 |
HIP 84175 |
25.30 |
| 2026-04-03 12:00 |
17:10:35.12 |
-27:54:19.9 |
HIP 84175 |
25.79 |
| 2026-04-04 00:00 |
17:10:33.08 |
-27:54:39.3 |
HIP 84175 |
26.32 |
| 2026-04-04 12:00 |
17:10:30.83 |
-27:54:58.3 |
HIP 84175 |
26.90 |
| 2026-04-05 00:00 |
17:10:28.35 |
-27:55:17.1 |
HIP 84175 |
27.52 |
| 2026-04-05 12:00 |
17:10:25.64 |
-27:55:35.5 |
HIP 83900 |
27.46 |
| 2026-04-06 00:00 |
17:10:22.71 |
-27:55:53.7 |
HIP 83900 |
26.77 |
| 2026-04-06 12:00 |
17:10:19.56 |
-27:56:11.5 |
HIP 83900 |
26.04 |
| 2026-04-07 00:00 |
17:10:16.18 |
-27:56:29.0 |
HIP 83900 |
25.29 |
| 2026-04-07 12:00 |
17:10:12.57 |
-27:56:46.1 |
HIP 83900 |
24.50 |
| 2026-04-08 00:00 |
17:10:08.74 |
-27:57:03.0 |
HIP 83900 |
23.68 |
| 2026-04-08 12:00 |
17:10:04.68 |
-27:57:19.5 |
HIP 83900 |
22.84 |
| 2026-04-09 00:00 |
17:10:00.40 |
-27:57:35.6 |
HIP 83900 |
21.97 |
| 2026-04-09 12:00 |
17:09:55.89 |
-27:57:51.5 |
HIP 83900 |
21.09 |
| 2026-04-10 00:00 |
17:09:51.16 |
-27:58:06.9 |
HIP 83900 |
20.18 |
| 2026-04-10 12:00 |
17:09:46.20 |
-27:58:22.0 |
HIP 83900 |
19.27 |
| 2026-04-11 00:00 |
17:09:41.02 |
-27:58:36.8 |
HIP 83900 |
18.35 |
| 2026-04-11 12:00 |
17:09:35.61 |
-27:58:51.2 |
HIP 83900 |
17.44 |
| 2026-04-12 00:00 |
17:09:29.98 |
-27:59:05.3 |
HIP 83900 |
16.55 |
| 2026-04-12 12:00 |
17:09:24.12 |
-27:59:18.9 |
HIP 83900 |
15.69 |
| 2026-04-13 00:00 |
17:09:18.04 |
-27:59:32.2 |
HIP 83859 |
14.59 |
| 2026-04-13 12:00 |
17:09:11.73 |
-27:59:45.1 |
HIP 83859 |
13.26 |
| 2026-04-14 00:00 |
17:09:05.21 |
-27:59:57.7 |
HIP 83859 |
11.91 |
| 2026-04-14 12:00 |
17:08:58.45 |
-28:00:09.8 |
HIP 83859 |
10.55 |
| 2026-04-15 00:00 |
17:08:51.48 |
-28:00:21.6 |
HIP 83859 |
9.20 |
| 2026-04-15 12:00 |
17:08:44.28 |
-28:00:32.9 |
HIP 83859 |
7.90 |
| 2026-04-16 00:00 |
17:08:36.86 |
-28:00:43.9 |
HIP 83859 |
6.70 |