| Parameter |
Value |
| Designation |
300P/Catalina |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2018-11-02T01:00:23.175360Z |
| Orbit solution date (soln_date, UTC) |
2023-11-14T12:36:26Z |
| Obs used |
148 |
| NEO |
Yes |
| M1 |
16.800 |
| K1 |
20.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-01-04.0000000 |
| e |
0.69162623 |
| q (au) |
0.832296 |
| a (au) |
2.698984 |
| i (deg) |
5.675932 |
| Ω (om, deg) |
95.686317 |
| ω (w, deg) |
222.865728 |
| M (ma, deg) |
292.861604 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.367 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.367 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2023-02-17 |
2023-04-11 |
+15.3858 |
+0.614 |
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 |
10:36:59.55 |
+13:22:11.3 |
HIP 51902 |
28.83 |
| 2026-07-29 12:00 |
10:37:27.13 |
+13:19:18.5 |
HIP 51968 |
28.03 |
| 2026-07-30 00:00 |
10:37:54.79 |
+13:16:25.2 |
HIP 51968 |
27.66 |
| 2026-07-30 12:00 |
10:38:22.52 |
+13:13:31.5 |
HIP 52107 |
28.51 |
| 2026-07-31 00:00 |
10:38:50.32 |
+13:10:37.4 |
HIP 52107 |
24.94 |
| 2026-07-31 12:00 |
10:39:18.20 |
+13:07:42.8 |
HIP 52107 |
23.24 |
| 2026-08-01 00:00 |
10:39:46.15 |
+13:04:47.7 |
HIP 52107 |
23.83 |
| 2026-08-01 12:00 |
10:40:14.16 |
+13:01:52.2 |
HIP 52306 |
16.60 |
| 2026-08-02 00:00 |
10:40:42.25 |
+12:58:56.3 |
HIP 52306 |
9.15 |
| 2026-08-02 12:00 |
10:41:10.41 |
+12:55:59.9 |
HIP 52306 |
1.72 |
| 2026-08-03 00:00 |
10:41:38.64 |
+12:53:03.1 |
HIP 52333 |
0.77 |
| 2026-08-03 12:00 |
10:42:06.94 |
+12:50:05.8 |
HIP 52333 |
6.80 |
| 2026-08-04 00:00 |
10:42:35.31 |
+12:47:08.1 |
HIP 52333 |
14.32 |
| 2026-08-04 12:00 |
10:43:03.75 |
+12:44:10.0 |
HIP 52333 |
21.86 |
| 2026-08-05 00:00 |
10:43:32.25 |
+12:41:11.4 |
HIP 52519 |
21.88 |
| 2026-08-05 12:00 |
10:44:00.82 |
+12:38:12.4 |
HIP 52519 |
22.13 |
| 2026-08-06 00:00 |
10:44:29.46 |
+12:35:13.0 |
HIP 52619 |
18.31 |
| 2026-08-06 12:00 |
10:44:58.17 |
+12:32:13.2 |
HIP 52619 |
10.69 |
| 2026-08-07 00:00 |
10:45:26.94 |
+12:29:12.9 |
HIP 52619 |
3.05 |
| 2026-08-07 12:00 |
10:45:55.78 |
+12:26:12.3 |
HIP 52619 |
4.61 |
| 2026-08-08 00:00 |
10:46:24.68 |
+12:23:11.2 |
HIP 52619 |
12.28 |
| 2026-08-08 12:00 |
10:46:53.65 |
+12:20:09.7 |
HIP 52619 |
19.98 |
| 2026-08-09 00:00 |
10:47:22.68 |
+12:17:07.8 |
HIP 52833 |
26.46 |
| 2026-08-09 12:00 |
10:47:51.77 |
+12:14:05.4 |
HIP 52833 |
21.13 |
| 2026-08-10 00:00 |
10:48:20.93 |
+12:11:02.7 |
HIP 52833 |
17.68 |
| 2026-08-10 12:00 |
10:48:50.15 |
+12:07:59.6 |
HIP 52833 |
17.28 |
| 2026-08-11 00:00 |
10:49:19.43 |
+12:04:56.1 |
HIP 52833 |
20.15 |
| 2026-08-11 12:00 |
10:49:48.77 |
+12:01:52.2 |
HIP 53014 |
19.85 |
| 2026-08-12 00:00 |
10:50:18.17 |
+11:58:47.9 |
HIP 53014 |
18.51 |
| 2026-08-12 12:00 |
10:50:47.63 |
+11:55:43.3 |
HIP 53014 |
20.34 |
| 2026-08-13 00:00 |
10:51:17.15 |
+11:52:38.2 |
HIP 53039 |
18.03 |
| 2026-08-13 12:00 |
10:51:46.73 |
+11:49:32.8 |
HIP 53039 |
17.52 |
| 2026-08-14 00:00 |
10:52:16.37 |
+11:46:27.0 |
HIP 53039 |
20.32 |
| 2026-08-14 12:00 |
10:52:46.06 |
+11:43:20.9 |
HIP 53115 |
24.74 |
| 2026-08-15 00:00 |
10:53:15.81 |
+11:40:14.4 |
HIP 53200 |
23.81 |
| 2026-08-15 12:00 |
10:53:45.61 |
+11:37:07.5 |
HIP 53200 |
24.02 |
| 2026-08-16 00:00 |
10:54:15.47 |
+11:34:00.3 |
HIP 53200 |
26.72 |
| 2026-08-16 12:00 |
10:54:45.39 |
+11:30:52.7 |
HIP 53200 |
31.27 |
| 2026-08-17 00:00 |
10:55:15.36 |
+11:27:44.8 |
HIP 53200 |
37.02 |
| 2026-08-17 12:00 |
10:55:45.38 |
+11:24:36.6 |
HIP 53200 |
43.49 |
| 2026-08-18 00:00 |
10:56:15.46 |
+11:21:28.0 |
HIP 53625 |
45.24 |
| 2026-08-18 12:00 |
10:56:45.58 |
+11:18:19.1 |
HIP 53625 |
38.19 |
| 2026-08-19 00:00 |
10:57:15.76 |
+11:15:09.8 |
HIP 53625 |
31.60 |