| Parameter |
Value |
| Designation |
C/1955 O1 (Honda) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1955-08-04T01:29:30.019200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:12Z |
| Obs used |
43 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1955-09-09.0000000 |
| e |
1.00111104 |
| q (au) |
0.884615 |
| a (au) |
-796.204707 |
| i (deg) |
107.523427 |
| Ω (om, deg) |
339.422185 |
| ω (w, deg) |
348.195749 |
| M (ma, deg) |
0.001577 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.055 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.055 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.520 |
| k |
0.800 |
| δ90 |
1.000 |
| 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 |
| 1955-08-06 |
1955-09-03 |
-19.9934 |
+0.158 |
| 1955-09-03 |
1955-11-23 |
+9.5187 |
-1.437 |
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 |
11:47:24.45 |
+25:33:07.0 |
HIP 57590 |
19.23 |
| 2026-03-26 12:00 |
11:47:23.17 |
+25:33:12.5 |
HIP 57590 |
19.38 |
| 2026-03-27 00:00 |
11:47:21.90 |
+25:33:17.9 |
HIP 57590 |
19.52 |
| 2026-03-27 12:00 |
11:47:20.64 |
+25:33:23.3 |
HIP 57590 |
19.67 |
| 2026-03-28 00:00 |
11:47:19.37 |
+25:33:28.5 |
HIP 57590 |
19.82 |
| 2026-03-28 12:00 |
11:47:18.10 |
+25:33:33.7 |
HIP 57590 |
19.98 |
| 2026-03-29 00:00 |
11:47:16.84 |
+25:33:38.8 |
HIP 57590 |
20.14 |
| 2026-03-29 12:00 |
11:47:15.58 |
+25:33:43.8 |
HIP 57590 |
20.30 |
| 2026-03-30 00:00 |
11:47:14.33 |
+25:33:48.8 |
HIP 57590 |
20.47 |
| 2026-03-30 12:00 |
11:47:13.07 |
+25:33:53.7 |
HIP 57590 |
20.64 |
| 2026-03-31 00:00 |
11:47:11.82 |
+25:33:58.5 |
HIP 57590 |
20.81 |
| 2026-03-31 12:00 |
11:47:10.57 |
+25:34:03.2 |
HIP 57590 |
20.99 |
| 2026-04-01 00:00 |
11:47:09.32 |
+25:34:07.8 |
HIP 57590 |
21.17 |
| 2026-04-01 12:00 |
11:47:08.08 |
+25:34:12.4 |
HIP 57590 |
21.35 |
| 2026-04-02 00:00 |
11:47:06.84 |
+25:34:16.8 |
HIP 57590 |
21.54 |
| 2026-04-02 12:00 |
11:47:05.60 |
+25:34:21.2 |
HIP 57590 |
21.72 |
| 2026-04-03 00:00 |
11:47:04.36 |
+25:34:25.6 |
HIP 57590 |
21.91 |
| 2026-04-03 12:00 |
11:47:03.13 |
+25:34:29.8 |
HIP 57590 |
22.11 |
| 2026-04-04 00:00 |
11:47:01.90 |
+25:34:34.0 |
HIP 57590 |
22.30 |
| 2026-04-04 12:00 |
11:47:00.68 |
+25:34:38.0 |
HIP 57590 |
22.50 |
| 2026-04-05 00:00 |
11:46:59.45 |
+25:34:42.0 |
HIP 57590 |
22.69 |
| 2026-04-05 12:00 |
11:46:58.24 |
+25:34:45.9 |
HIP 57590 |
22.89 |
| 2026-04-06 00:00 |
11:46:57.02 |
+25:34:49.8 |
HIP 57590 |
23.10 |
| 2026-04-06 12:00 |
11:46:55.81 |
+25:34:53.5 |
HIP 57590 |
23.30 |
| 2026-04-07 00:00 |
11:46:54.60 |
+25:34:57.2 |
HIP 57590 |
23.50 |
| 2026-04-07 12:00 |
11:46:53.40 |
+25:35:00.8 |
HIP 57590 |
23.71 |
| 2026-04-08 00:00 |
11:46:52.20 |
+25:35:04.3 |
HIP 57590 |
23.92 |
| 2026-04-08 12:00 |
11:46:51.00 |
+25:35:07.7 |
HIP 57590 |
24.12 |
| 2026-04-09 00:00 |
11:46:49.81 |
+25:35:11.1 |
HIP 57590 |
24.33 |
| 2026-04-09 12:00 |
11:46:48.62 |
+25:35:14.3 |
HIP 57590 |
24.55 |
| 2026-04-10 00:00 |
11:46:47.44 |
+25:35:17.5 |
HIP 57590 |
24.76 |
| 2026-04-10 12:00 |
11:46:46.26 |
+25:35:20.6 |
HIP 57590 |
24.97 |
| 2026-04-11 00:00 |
11:46:45.09 |
+25:35:23.6 |
HIP 57590 |
25.18 |
| 2026-04-11 12:00 |
11:46:43.92 |
+25:35:26.5 |
HIP 57590 |
25.40 |
| 2026-04-12 00:00 |
11:46:42.75 |
+25:35:29.3 |
HIP 57590 |
25.61 |
| 2026-04-12 12:00 |
11:46:41.59 |
+25:35:32.1 |
HIP 57590 |
25.83 |
| 2026-04-13 00:00 |
11:46:40.44 |
+25:35:34.7 |
HIP 57373 |
25.82 |
| 2026-04-13 12:00 |
11:46:39.29 |
+25:35:37.3 |
HIP 57373 |
25.65 |
| 2026-04-14 00:00 |
11:46:38.14 |
+25:35:39.8 |
HIP 57373 |
25.49 |
| 2026-04-14 12:00 |
11:46:37.00 |
+25:35:42.2 |
HIP 57373 |
25.34 |
| 2026-04-15 00:00 |
11:46:35.86 |
+25:35:44.6 |
HIP 57373 |
25.18 |
| 2026-04-15 12:00 |
11:46:34.73 |
+25:35:46.8 |
HIP 57373 |
25.03 |
| 2026-04-16 00:00 |
11:46:33.61 |
+25:35:48.9 |
HIP 57373 |
24.89 |