| Parameter |
Value |
| Designation |
61P/Shajn-Schaldach |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-10-23T19:34:06.749760Z |
| Orbit solution date (soln_date, UTC) |
2024-05-14T12:48:19Z |
| Obs used |
895 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
13.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-09-30.0000000 |
| e |
0.42420483 |
| q (au) |
2.125862 |
| a (au) |
3.692046 |
| i (deg) |
6.000525 |
| Ω (om, deg) |
162.968506 |
| ω (w, deg) |
221.656974 |
| M (ma, deg) |
356.691277 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.270 + 3.029\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.270 |
| n |
3.029 |
| gf |
0.905 |
| gb |
-0.772 |
| k |
0.996 |
| δ90 |
5.457 |
| 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 |
| 2022-05-06 |
2022-10-23 |
-6.7763 |
+2.138 |
| 2022-10-23 |
2024-02-09 |
+10.6603 |
-3.646 |
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 |
13:15:34.89 |
-03:27:45.6 |
HIP 64721 |
21.75 |
| 2026-07-29 12:00 |
13:15:46.97 |
-03:29:13.5 |
HIP 64721 |
22.62 |
| 2026-07-30 00:00 |
13:15:59.18 |
-03:30:42.0 |
HIP 64731 |
23.69 |
| 2026-07-30 12:00 |
13:16:11.51 |
-03:32:11.2 |
HIP 64731 |
22.28 |
| 2026-07-31 00:00 |
13:16:23.97 |
-03:33:41.1 |
HIP 64731 |
21.33 |
| 2026-07-31 12:00 |
13:16:36.56 |
-03:35:11.6 |
HIP 64731 |
20.92 |
| 2026-08-01 00:00 |
13:16:49.28 |
-03:36:42.7 |
HIP 64731 |
21.09 |
| 2026-08-01 12:00 |
13:17:02.11 |
-03:38:14.5 |
HIP 64731 |
21.85 |
| 2026-08-02 00:00 |
13:17:15.08 |
-03:39:47.0 |
HIP 64731 |
23.15 |
| 2026-08-02 12:00 |
13:17:28.16 |
-03:41:20.0 |
HIP 64731 |
24.93 |
| 2026-08-03 00:00 |
13:17:41.37 |
-03:42:53.7 |
HIP 64731 |
27.09 |
| 2026-08-03 12:00 |
13:17:54.70 |
-03:44:28.0 |
HIP 64731 |
29.57 |
| 2026-08-04 00:00 |
13:18:08.15 |
-03:46:02.9 |
HIP 64731 |
32.31 |
| 2026-08-04 12:00 |
13:18:21.72 |
-03:47:38.4 |
HIP 64731 |
35.25 |
| 2026-08-05 00:00 |
13:18:35.41 |
-03:49:14.5 |
HIP 64731 |
38.36 |
| 2026-08-05 12:00 |
13:18:49.22 |
-03:50:51.2 |
HIP 64731 |
41.61 |
| 2026-08-06 00:00 |
13:19:03.15 |
-03:52:28.4 |
HIP 64731 |
44.98 |
| 2026-08-06 12:00 |
13:19:17.20 |
-03:54:06.3 |
HIP 64731 |
48.44 |
| 2026-08-07 00:00 |
13:19:31.37 |
-03:55:44.8 |
HIP 64731 |
51.99 |
| 2026-08-07 12:00 |
13:19:45.65 |
-03:57:23.8 |
HIP 64965 |
54.48 |
| 2026-08-08 00:00 |
13:20:00.05 |
-03:59:03.4 |
HIP 65335 |
51.71 |
| 2026-08-08 12:00 |
13:20:14.57 |
-04:00:43.5 |
HIP 65335 |
48.10 |
| 2026-08-09 00:00 |
13:20:29.20 |
-04:02:24.3 |
HIP 65335 |
44.53 |
| 2026-08-09 12:00 |
13:20:43.94 |
-04:04:05.5 |
HIP 65335 |
41.01 |
| 2026-08-10 00:00 |
13:20:58.80 |
-04:05:47.3 |
HIP 65335 |
37.57 |
| 2026-08-10 12:00 |
13:21:13.78 |
-04:07:29.7 |
HIP 65335 |
34.25 |
| 2026-08-11 00:00 |
13:21:28.86 |
-04:09:12.6 |
HIP 65335 |
31.09 |
| 2026-08-11 12:00 |
13:21:44.06 |
-04:10:56.0 |
HIP 65335 |
28.16 |
| 2026-08-12 00:00 |
13:21:59.37 |
-04:12:40.0 |
HIP 65335 |
25.55 |
| 2026-08-12 12:00 |
13:22:14.79 |
-04:14:24.4 |
HIP 65335 |
23.40 |
| 2026-08-13 00:00 |
13:22:30.31 |
-04:16:09.4 |
HIP 65335 |
21.85 |
| 2026-08-13 12:00 |
13:22:45.95 |
-04:17:54.8 |
HIP 65335 |
21.04 |
| 2026-08-14 00:00 |
13:23:01.70 |
-04:19:40.8 |
HIP 65392 |
20.62 |
| 2026-08-14 12:00 |
13:23:17.55 |
-04:21:27.3 |
HIP 65392 |
16.43 |
| 2026-08-15 00:00 |
13:23:33.51 |
-04:23:14.2 |
HIP 65392 |
12.32 |
| 2026-08-15 12:00 |
13:23:49.57 |
-04:25:01.6 |
HIP 65392 |
8.43 |
| 2026-08-16 00:00 |
13:24:05.74 |
-04:26:49.5 |
HIP 65392 |
5.38 |
| 2026-08-16 12:00 |
13:24:22.02 |
-04:28:37.9 |
HIP 65392 |
5.08 |
| 2026-08-17 00:00 |
13:24:38.40 |
-04:30:26.7 |
HIP 65392 |
7.91 |
| 2026-08-17 12:00 |
13:24:54.88 |
-04:32:15.9 |
HIP 65392 |
11.82 |
| 2026-08-18 00:00 |
13:25:11.46 |
-04:34:05.6 |
HIP 65392 |
16.07 |
| 2026-08-18 12:00 |
13:25:28.14 |
-04:35:55.8 |
HIP 65570 |
19.67 |
| 2026-08-19 00:00 |
13:25:44.93 |
-04:37:46.3 |
HIP 65570 |
17.21 |