| Parameter |
Value |
| Designation |
C/1932 Y1 (Dodwell-Forbes) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1932-12-30T12:36:55.002240Z |
| Orbit solution date (soln_date, UTC) |
2023-12-04T20:32:29Z |
| Obs used |
23 |
| NEO |
- |
| M1 |
9.100 |
| K1 |
15.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1933-01-20.0000000 |
| e |
0.97216017 |
| q (au) |
1.130765 |
| a (au) |
40.616795 |
| i (deg) |
24.502460 |
| Ω (om, deg) |
78.589152 |
| ω (w, deg) |
327.357273 |
| M (ma, deg) |
0.077957 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.943 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.943 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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) |
| 2026-06-01 00:00 |
15:06:51.95 |
-02:53:08.6 |
HIP 73972 |
35.35 |
| 2026-06-01 12:00 |
15:06:50.57 |
-02:53:05.2 |
HIP 73972 |
35.32 |
| 2026-06-02 00:00 |
15:06:49.19 |
-02:53:01.9 |
HIP 73972 |
35.29 |
| 2026-06-02 12:00 |
15:06:47.82 |
-02:52:58.6 |
HIP 73972 |
35.27 |
| 2026-06-03 00:00 |
15:06:46.46 |
-02:52:55.4 |
HIP 73972 |
35.24 |
| 2026-06-03 12:00 |
15:06:45.10 |
-02:52:52.3 |
HIP 73972 |
35.23 |
| 2026-06-04 00:00 |
15:06:43.75 |
-02:52:49.2 |
HIP 73972 |
35.22 |
| 2026-06-04 12:00 |
15:06:42.40 |
-02:52:46.2 |
HIP 73972 |
35.21 |
| 2026-06-05 00:00 |
15:06:41.05 |
-02:52:43.3 |
HIP 73972 |
35.20 |
| 2026-06-05 12:00 |
15:06:39.72 |
-02:52:40.4 |
HIP 73972 |
35.20 |
| 2026-06-06 00:00 |
15:06:38.38 |
-02:52:37.6 |
HIP 73972 |
35.21 |
| 2026-06-06 12:00 |
15:06:37.06 |
-02:52:34.9 |
HIP 73972 |
35.22 |
| 2026-06-07 00:00 |
15:06:35.74 |
-02:52:32.2 |
HIP 73972 |
35.23 |
| 2026-06-07 12:00 |
15:06:34.42 |
-02:52:29.6 |
HIP 73972 |
35.25 |
| 2026-06-08 00:00 |
15:06:33.11 |
-02:52:27.1 |
HIP 73972 |
35.27 |
| 2026-06-08 12:00 |
15:06:31.81 |
-02:52:24.6 |
HIP 73972 |
35.29 |
| 2026-06-09 00:00 |
15:06:30.51 |
-02:52:22.3 |
HIP 73972 |
35.32 |
| 2026-06-09 12:00 |
15:06:29.22 |
-02:52:19.9 |
HIP 73972 |
35.35 |
| 2026-06-10 00:00 |
15:06:27.94 |
-02:52:17.7 |
HIP 73972 |
35.39 |
| 2026-06-10 12:00 |
15:06:26.66 |
-02:52:15.5 |
HIP 73972 |
35.43 |
| 2026-06-11 00:00 |
15:06:25.39 |
-02:52:13.4 |
HIP 73972 |
35.47 |
| 2026-06-11 12:00 |
15:06:24.12 |
-02:52:11.4 |
HIP 73972 |
35.51 |
| 2026-06-12 00:00 |
15:06:22.86 |
-02:52:09.4 |
HIP 73708 |
35.56 |
| 2026-06-12 12:00 |
15:06:21.61 |
-02:52:07.5 |
HIP 73708 |
35.24 |
| 2026-06-13 00:00 |
15:06:20.37 |
-02:52:05.7 |
HIP 73708 |
34.93 |
| 2026-06-13 12:00 |
15:06:19.13 |
-02:52:03.9 |
HIP 73708 |
34.62 |
| 2026-06-14 00:00 |
15:06:17.90 |
-02:52:02.2 |
HIP 73708 |
34.32 |
| 2026-06-14 12:00 |
15:06:16.67 |
-02:52:00.6 |
HIP 73708 |
34.01 |
| 2026-06-15 00:00 |
15:06:15.46 |
-02:51:59.1 |
HIP 73708 |
33.71 |
| 2026-06-15 12:00 |
15:06:14.25 |
-02:51:57.6 |
HIP 73708 |
33.40 |
| 2026-06-16 00:00 |
15:06:13.05 |
-02:51:56.2 |
HIP 73708 |
33.10 |
| 2026-06-16 12:00 |
15:06:11.85 |
-02:51:54.8 |
HIP 73708 |
32.80 |
| 2026-06-17 00:00 |
15:06:10.67 |
-02:51:53.6 |
HIP 73708 |
32.51 |
| 2026-06-17 12:00 |
15:06:09.49 |
-02:51:52.4 |
HIP 73708 |
32.21 |
| 2026-06-18 00:00 |
15:06:08.32 |
-02:51:51.3 |
HIP 73708 |
31.92 |
| 2026-06-18 12:00 |
15:06:07.16 |
-02:51:50.2 |
HIP 73708 |
31.63 |
| 2026-06-19 00:00 |
15:06:06.00 |
-02:51:49.3 |
HIP 73708 |
31.34 |
| 2026-06-19 12:00 |
15:06:04.86 |
-02:51:48.4 |
HIP 73708 |
31.05 |
| 2026-06-20 00:00 |
15:06:03.72 |
-02:51:47.5 |
HIP 73708 |
30.77 |
| 2026-06-20 12:00 |
15:06:02.59 |
-02:51:46.8 |
HIP 73708 |
30.49 |
| 2026-06-21 00:00 |
15:06:01.47 |
-02:51:46.1 |
HIP 73708 |
30.21 |
| 2026-06-21 12:00 |
15:06:00.35 |
-02:51:45.5 |
HIP 73708 |
29.93 |
| 2026-06-22 00:00 |
15:05:59.25 |
-02:51:44.9 |
HIP 73708 |
29.65 |