| 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) |
| 2026-06-01 00:00 |
11:45:22.09 |
+25:33:03.7 |
HIP 57265 |
10.42 |
| 2026-06-01 12:00 |
11:45:21.74 |
+25:32:58.3 |
HIP 57265 |
10.34 |
| 2026-06-02 00:00 |
11:45:21.39 |
+25:32:52.7 |
HIP 57265 |
10.25 |
| 2026-06-02 12:00 |
11:45:21.06 |
+25:32:47.1 |
HIP 57265 |
10.17 |
| 2026-06-03 00:00 |
11:45:20.74 |
+25:32:41.4 |
HIP 57265 |
10.09 |
| 2026-06-03 12:00 |
11:45:20.42 |
+25:32:35.6 |
HIP 57265 |
10.02 |
| 2026-06-04 00:00 |
11:45:20.12 |
+25:32:29.8 |
HIP 57265 |
9.95 |
| 2026-06-04 12:00 |
11:45:19.82 |
+25:32:23.9 |
HIP 57265 |
9.88 |
| 2026-06-05 00:00 |
11:45:19.54 |
+25:32:18.0 |
HIP 57265 |
9.81 |
| 2026-06-05 12:00 |
11:45:19.27 |
+25:32:11.9 |
HIP 57265 |
9.75 |
| 2026-06-06 00:00 |
11:45:19.01 |
+25:32:05.8 |
HIP 57265 |
9.69 |
| 2026-06-06 12:00 |
11:45:18.75 |
+25:31:59.7 |
HIP 57265 |
9.64 |
| 2026-06-07 00:00 |
11:45:18.51 |
+25:31:53.5 |
HIP 57265 |
9.59 |
| 2026-06-07 12:00 |
11:45:18.28 |
+25:31:47.2 |
HIP 57265 |
9.54 |
| 2026-06-08 00:00 |
11:45:18.06 |
+25:31:40.8 |
HIP 57265 |
9.49 |
| 2026-06-08 12:00 |
11:45:17.85 |
+25:31:34.4 |
HIP 57265 |
9.45 |
| 2026-06-09 00:00 |
11:45:17.65 |
+25:31:27.9 |
HIP 57265 |
9.41 |
| 2026-06-09 12:00 |
11:45:17.46 |
+25:31:21.4 |
HIP 57265 |
9.38 |
| 2026-06-10 00:00 |
11:45:17.28 |
+25:31:14.8 |
HIP 57265 |
9.35 |
| 2026-06-10 12:00 |
11:45:17.11 |
+25:31:08.1 |
HIP 57265 |
9.33 |
| 2026-06-11 00:00 |
11:45:16.95 |
+25:31:01.4 |
HIP 57265 |
9.30 |
| 2026-06-11 12:00 |
11:45:16.80 |
+25:30:54.6 |
HIP 57265 |
9.29 |
| 2026-06-12 00:00 |
11:45:16.66 |
+25:30:47.7 |
HIP 57265 |
9.27 |
| 2026-06-12 12:00 |
11:45:16.53 |
+25:30:40.8 |
HIP 57265 |
9.26 |
| 2026-06-13 00:00 |
11:45:16.41 |
+25:30:33.8 |
HIP 57265 |
9.25 |
| 2026-06-13 12:00 |
11:45:16.31 |
+25:30:26.8 |
HIP 57265 |
9.25 |
| 2026-06-14 00:00 |
11:45:16.21 |
+25:30:19.7 |
HIP 57265 |
9.25 |
| 2026-06-14 12:00 |
11:45:16.13 |
+25:30:12.5 |
HIP 57265 |
9.26 |
| 2026-06-15 00:00 |
11:45:16.05 |
+25:30:05.3 |
HIP 57265 |
9.27 |
| 2026-06-15 12:00 |
11:45:15.99 |
+25:29:58.0 |
HIP 57265 |
9.28 |
| 2026-06-16 00:00 |
11:45:15.93 |
+25:29:50.7 |
HIP 57265 |
9.30 |
| 2026-06-16 12:00 |
11:45:15.89 |
+25:29:43.3 |
HIP 57265 |
9.33 |
| 2026-06-17 00:00 |
11:45:15.86 |
+25:29:35.9 |
HIP 57265 |
9.35 |
| 2026-06-17 12:00 |
11:45:15.83 |
+25:29:28.4 |
HIP 57265 |
9.38 |
| 2026-06-18 00:00 |
11:45:15.82 |
+25:29:20.9 |
HIP 57265 |
9.42 |
| 2026-06-18 12:00 |
11:45:15.82 |
+25:29:13.3 |
HIP 57265 |
9.46 |
| 2026-06-19 00:00 |
11:45:15.83 |
+25:29:05.6 |
HIP 57265 |
9.50 |
| 2026-06-19 12:00 |
11:45:15.85 |
+25:28:57.9 |
HIP 57265 |
9.55 |
| 2026-06-20 00:00 |
11:45:15.88 |
+25:28:50.1 |
HIP 57265 |
9.60 |
| 2026-06-20 12:00 |
11:45:15.92 |
+25:28:42.3 |
HIP 57265 |
9.65 |
| 2026-06-21 00:00 |
11:45:15.97 |
+25:28:34.5 |
HIP 57265 |
9.71 |
| 2026-06-21 12:00 |
11:45:16.03 |
+25:28:26.5 |
HIP 57265 |
9.77 |
| 2026-06-22 00:00 |
11:45:16.10 |
+25:28:18.6 |
HIP 57265 |
9.84 |