| 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) |
| 2026-09-20 00:00 |
13:46:37.79 |
-06:46:38.9 |
HIP 67289 |
12.59 |
| 2026-09-20 12:00 |
13:46:59.71 |
-06:48:46.3 |
HIP 67289 |
9.07 |
| 2026-09-21 00:00 |
13:47:21.70 |
-06:50:53.8 |
HIP 67289 |
8.62 |
| 2026-09-21 12:00 |
13:47:43.74 |
-06:53:01.3 |
HIP 67355 |
8.95 |
| 2026-09-22 00:00 |
13:48:05.83 |
-06:55:09.0 |
HIP 67355 |
5.76 |
| 2026-09-22 12:00 |
13:48:27.99 |
-06:57:16.7 |
HIP 67355 |
7.46 |
| 2026-09-23 00:00 |
13:48:50.20 |
-06:59:24.4 |
HIP 67355 |
12.16 |
| 2026-09-23 12:00 |
13:49:12.46 |
-07:01:32.3 |
HIP 67433 |
17.26 |
| 2026-09-24 00:00 |
13:49:34.78 |
-07:03:40.2 |
HIP 67433 |
16.03 |
| 2026-09-24 12:00 |
13:49:57.16 |
-07:05:48.1 |
HIP 67559 |
10.83 |
| 2026-09-25 00:00 |
13:50:19.58 |
-07:07:56.1 |
HIP 67559 |
4.89 |
| 2026-09-25 12:00 |
13:50:42.06 |
-07:10:04.2 |
HIP 67559 |
1.24 |
| 2026-09-26 00:00 |
13:51:04.60 |
-07:12:12.2 |
HIP 67559 |
7.11 |
| 2026-09-26 12:00 |
13:51:27.18 |
-07:14:20.4 |
HIP 67658 |
5.77 |
| 2026-09-27 00:00 |
13:51:49.82 |
-07:16:28.5 |
HIP 67658 |
6.27 |
| 2026-09-27 12:00 |
13:52:12.50 |
-07:18:36.7 |
HIP 67658 |
10.85 |
| 2026-09-28 00:00 |
13:52:35.24 |
-07:20:44.9 |
HIP 67658 |
16.39 |
| 2026-09-28 12:00 |
13:52:58.02 |
-07:22:53.2 |
HIP 67658 |
22.20 |
| 2026-09-29 00:00 |
13:53:20.86 |
-07:25:01.4 |
HIP 67658 |
28.12 |
| 2026-09-29 12:00 |
13:53:43.74 |
-07:27:09.7 |
HIP 67718 |
32.20 |
| 2026-09-30 00:00 |
13:54:06.68 |
-07:29:18.0 |
HIP 67718 |
34.65 |
| 2026-09-30 12:00 |
13:54:29.66 |
-07:31:26.3 |
HIP 67953 |
32.86 |
| 2026-10-01 00:00 |
13:54:52.69 |
-07:33:34.5 |
HIP 67953 |
29.98 |
| 2026-10-01 12:00 |
13:55:15.76 |
-07:35:42.8 |
HIP 68116 |
27.97 |
| 2026-10-02 00:00 |
13:55:38.88 |
-07:37:51.1 |
HIP 68116 |
25.27 |
| 2026-10-02 12:00 |
13:56:02.05 |
-07:39:59.4 |
HIP 68116 |
23.86 |
| 2026-10-03 00:00 |
13:56:25.26 |
-07:42:07.6 |
HIP 68116 |
23.98 |
| 2026-10-03 12:00 |
13:56:48.52 |
-07:44:15.9 |
HIP 68116 |
25.62 |
| 2026-10-04 00:00 |
13:57:11.83 |
-07:46:24.1 |
HIP 68116 |
28.52 |
| 2026-10-04 12:00 |
13:57:35.17 |
-07:48:32.3 |
HIP 68116 |
32.34 |
| 2026-10-05 00:00 |
13:57:58.56 |
-07:50:40.4 |
HIP 68398 |
36.56 |
| 2026-10-05 12:00 |
13:58:21.99 |
-07:52:48.5 |
HIP 68398 |
30.52 |
| 2026-10-06 00:00 |
13:58:45.47 |
-07:54:56.6 |
HIP 68398 |
24.54 |
| 2026-10-06 12:00 |
13:59:08.98 |
-07:57:04.6 |
HIP 68398 |
18.69 |
| 2026-10-07 00:00 |
13:59:32.54 |
-07:59:12.6 |
HIP 68398 |
13.16 |
| 2026-10-07 12:00 |
13:59:56.14 |
-08:01:20.5 |
HIP 68398 |
8.61 |
| 2026-10-08 00:00 |
14:00:19.78 |
-08:03:28.3 |
HIP 68398 |
7.25 |
| 2026-10-08 12:00 |
14:00:43.45 |
-08:05:36.1 |
HIP 68453 |
2.41 |
| 2026-10-09 00:00 |
14:01:07.17 |
-08:07:43.8 |
HIP 68453 |
5.19 |
| 2026-10-09 12:00 |
14:01:30.92 |
-08:09:51.4 |
HIP 68535 |
8.51 |
| 2026-10-10 00:00 |
14:01:54.71 |
-08:11:58.9 |
HIP 68535 |
5.39 |
| 2026-10-10 12:00 |
14:02:18.53 |
-08:14:06.4 |
HIP 68535 |
8.01 |
| 2026-10-11 00:00 |
14:02:42.39 |
-08:16:13.7 |
HIP 68535 |
13.35 |