C/1955 O1 (Honda)
| 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) |
| 2026-02-03 00:00 |
11:49:25.69 |
+25:18:48.4 |
HIP 57815 |
26.10 |
| 2026-02-03 12:00 |
11:49:24.75 |
+25:18:58.5 |
HIP 57815 |
26.30 |
| 2026-02-04 00:00 |
11:49:23.80 |
+25:19:08.6 |
HIP 57815 |
26.51 |
| 2026-02-04 12:00 |
11:49:22.84 |
+25:19:18.7 |
HIP 57815 |
26.72 |
| 2026-02-05 00:00 |
11:49:21.87 |
+25:19:28.8 |
HIP 57815 |
26.93 |
| 2026-02-05 12:00 |
11:49:20.90 |
+25:19:38.9 |
HIP 57815 |
27.15 |
| 2026-02-06 00:00 |
11:49:19.91 |
+25:19:49.0 |
HIP 57815 |
27.37 |
| 2026-02-06 12:00 |
11:49:18.92 |
+25:19:59.1 |
HIP 57815 |
27.59 |
| 2026-02-07 00:00 |
11:49:17.93 |
+25:20:09.2 |
HIP 57815 |
27.81 |
| 2026-02-07 12:00 |
11:49:16.92 |
+25:20:19.2 |
HIP 57815 |
28.04 |
| 2026-02-08 00:00 |
11:49:15.91 |
+25:20:29.2 |
HIP 57815 |
28.27 |
| 2026-02-08 12:00 |
11:49:14.89 |
+25:20:39.3 |
HIP 57590 |
28.34 |
| 2026-02-09 00:00 |
11:49:13.87 |
+25:20:49.3 |
HIP 57590 |
28.09 |
| 2026-02-09 12:00 |
11:49:12.84 |
+25:20:59.2 |
HIP 57590 |
27.85 |
| 2026-02-10 00:00 |
11:49:11.80 |
+25:21:09.2 |
HIP 57590 |
27.60 |
| 2026-02-10 12:00 |
11:49:10.75 |
+25:21:19.1 |
HIP 57590 |
27.36 |
| 2026-02-11 00:00 |
11:49:09.70 |
+25:21:29.1 |
HIP 57590 |
27.12 |
| 2026-02-11 12:00 |
11:49:08.64 |
+25:21:39.0 |
HIP 57590 |
26.88 |
| 2026-02-12 00:00 |
11:49:07.58 |
+25:21:48.9 |
HIP 57590 |
26.64 |
| 2026-02-12 12:00 |
11:49:06.50 |
+25:21:58.7 |
HIP 57590 |
26.40 |
| 2026-02-13 00:00 |
11:49:05.43 |
+25:22:08.6 |
HIP 57590 |
26.16 |
| 2026-02-13 12:00 |
11:49:04.34 |
+25:22:18.4 |
HIP 57590 |
25.92 |
| 2026-02-14 00:00 |
11:49:03.25 |
+25:22:28.2 |
HIP 57590 |
25.68 |
| 2026-02-14 12:00 |
11:49:02.16 |
+25:22:37.9 |
HIP 57590 |
25.45 |
| 2026-02-15 00:00 |
11:49:01.05 |
+25:22:47.7 |
HIP 57590 |
25.21 |
| 2026-02-15 12:00 |
11:48:59.94 |
+25:22:57.4 |
HIP 57590 |
24.98 |
| 2026-02-16 00:00 |
11:48:58.83 |
+25:23:07.1 |
HIP 57590 |
24.75 |
| 2026-02-16 12:00 |
11:48:57.71 |
+25:23:16.7 |
HIP 57590 |
24.52 |
| 2026-02-17 00:00 |
11:48:56.58 |
+25:23:26.4 |
HIP 57590 |
24.29 |
| 2026-02-17 12:00 |
11:48:55.45 |
+25:23:36.0 |
HIP 57590 |
24.06 |
| 2026-02-18 00:00 |
11:48:54.32 |
+25:23:45.5 |
HIP 57590 |
23.84 |
| 2026-02-18 12:00 |
11:48:53.18 |
+25:23:55.0 |
HIP 57590 |
23.61 |
| 2026-02-19 00:00 |
11:48:52.03 |
+25:24:04.5 |
HIP 57590 |
23.39 |
| 2026-02-19 12:00 |
11:48:50.88 |
+25:24:14.0 |
HIP 57590 |
23.17 |
| 2026-02-20 00:00 |
11:48:49.72 |
+25:24:23.4 |
HIP 57590 |
22.96 |
| 2026-02-20 12:00 |
11:48:48.56 |
+25:24:32.8 |
HIP 57590 |
22.74 |
| 2026-02-21 00:00 |
11:48:47.39 |
+25:24:42.2 |
HIP 57590 |
22.53 |
| 2026-02-21 12:00 |
11:48:46.22 |
+25:24:51.5 |
HIP 57590 |
22.32 |
| 2026-02-22 00:00 |
11:48:45.04 |
+25:25:00.8 |
HIP 57590 |
22.11 |
| 2026-02-22 12:00 |
11:48:43.86 |
+25:25:10.1 |
HIP 57590 |
21.91 |
| 2026-02-23 00:00 |
11:48:42.67 |
+25:25:19.3 |
HIP 57590 |
21.71 |
| 2026-02-23 12:00 |
11:48:41.48 |
+25:25:28.4 |
HIP 57590 |
21.51 |
| 2026-02-24 00:00 |
11:48:40.29 |
+25:25:37.6 |
HIP 57590 |
21.32 |