C/1956 R1 (Arend-Roland)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/1956 R1 (Arend-Roland) |
| Type | C |
| Perihelion (tp_cal, UTC) | 1957-04-08T00:46:40.293120Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:29:12Z |
| Obs used | 57 |
| NEO | - |
| M1 | - |
| K1 | - |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 1957-07-09.0000000 |
| e | 1.00024806 |
| q (au) | 0.316043 |
| a (au) | -1274.056032 |
| i (deg) | 119.944301 |
| Ω (om, deg) | 215.855361 |
| ω (w, deg) | 308.774543 |
| M (ma, deg) | 0.001993 |
Magnitude
Scatter + Global Linear
$$ M_a = (5.382 + 3.093\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 5.382 |
| n | 3.093 |
| gf | 0.800 |
| gb | -0.500 |
| k | 1.000 |
| 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 |
|---|---|---|---|
| 1956-11-20 | 1957-04-06 | -0.6577 | +0.271 |
| 1957-04-10 | 1957-05-20 | -2.0830 | -0.252 |
| 1957-05-20 | 1957-05-30 | -10.4996 | +0.237 |
| 1957-05-30 | 1957-12-03 | +5.1007 | -1.102 |
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 | 03:59:08.43 | +68:35:40.1 | HIP 18574 | 14.60 |
| 2026-06-01 12:00 | 03:59:11.65 | +68:35:44.3 | HIP 18574 | 14.73 |
| 2026-06-02 00:00 | 03:59:14.87 | +68:35:48.6 | HIP 18574 | 14.88 |
| 2026-06-02 12:00 | 03:59:18.09 | +68:35:53.0 | HIP 18574 | 15.02 |
| 2026-06-03 00:00 | 03:59:21.30 | +68:35:57.5 | HIP 18574 | 15.18 |
| 2026-06-03 12:00 | 03:59:24.51 | +68:36:02.1 | HIP 18574 | 15.34 |
| 2026-06-04 00:00 | 03:59:27.71 | +68:36:06.9 | HIP 18574 | 15.50 |
| 2026-06-04 12:00 | 03:59:30.91 | +68:36:11.7 | HIP 18574 | 15.68 |
| 2026-06-05 00:00 | 03:59:34.10 | +68:36:16.6 | HIP 18574 | 15.85 |
| 2026-06-05 12:00 | 03:59:37.29 | +68:36:21.7 | HIP 18574 | 16.03 |
| 2026-06-06 00:00 | 03:59:40.47 | +68:36:26.8 | HIP 18574 | 16.22 |
| 2026-06-06 12:00 | 03:59:43.65 | +68:36:32.1 | HIP 18574 | 16.41 |
| 2026-06-07 00:00 | 03:59:46.82 | +68:36:37.5 | HIP 18574 | 16.61 |
| 2026-06-07 12:00 | 03:59:49.98 | +68:36:42.9 | HIP 18574 | 16.81 |
| 2026-06-08 00:00 | 03:59:53.14 | +68:36:48.5 | HIP 18574 | 17.02 |
| 2026-06-08 12:00 | 03:59:56.29 | +68:36:54.1 | HIP 18800 | 16.78 |
| 2026-06-09 00:00 | 03:59:59.44 | +68:37:00.0 | HIP 18800 | 16.54 |
| 2026-06-09 12:00 | 04:00:02.57 | +68:37:05.8 | HIP 18800 | 16.30 |
| 2026-06-10 00:00 | 04:00:05.70 | +68:37:11.8 | HIP 18800 | 16.07 |
| 2026-06-10 12:00 | 04:00:08.83 | +68:37:17.8 | HIP 18800 | 15.83 |
| 2026-06-11 00:00 | 04:00:11.94 | +68:37:24.0 | HIP 18800 | 15.59 |
| 2026-06-11 12:00 | 04:00:15.05 | +68:37:30.3 | HIP 18800 | 15.36 |
| 2026-06-12 00:00 | 04:00:18.15 | +68:37:36.6 | HIP 18800 | 15.13 |
| 2026-06-12 12:00 | 04:00:21.24 | +68:37:43.1 | HIP 18800 | 14.89 |
| 2026-06-13 00:00 | 04:00:24.32 | +68:37:49.7 | HIP 18800 | 14.66 |
| 2026-06-13 12:00 | 04:00:27.40 | +68:37:56.4 | HIP 18800 | 14.44 |
| 2026-06-14 00:00 | 04:00:30.46 | +68:38:03.1 | HIP 18800 | 14.21 |
| 2026-06-14 12:00 | 04:00:33.52 | +68:38:10.0 | HIP 18800 | 13.98 |
| 2026-06-15 00:00 | 04:00:36.56 | +68:38:17.0 | HIP 18800 | 13.76 |
| 2026-06-15 12:00 | 04:00:39.60 | +68:38:24.0 | HIP 18800 | 13.54 |
| 2026-06-16 00:00 | 04:00:42.63 | +68:38:31.2 | HIP 18800 | 13.32 |
| 2026-06-16 12:00 | 04:00:45.64 | +68:38:38.4 | HIP 18800 | 13.10 |
| 2026-06-17 00:00 | 04:00:48.65 | +68:38:45.8 | HIP 18800 | 12.88 |
| 2026-06-17 12:00 | 04:00:51.65 | +68:38:53.2 | HIP 18800 | 12.67 |
| 2026-06-18 00:00 | 04:00:54.63 | +68:39:00.7 | HIP 18800 | 12.46 |
| 2026-06-18 12:00 | 04:00:57.61 | +68:39:08.4 | HIP 18800 | 12.25 |
| 2026-06-19 00:00 | 04:01:00.57 | +68:39:16.1 | HIP 18800 | 12.04 |
| 2026-06-19 12:00 | 04:01:03.52 | +68:39:23.9 | HIP 18800 | 11.84 |
| 2026-06-20 00:00 | 04:01:06.46 | +68:39:31.8 | HIP 18800 | 11.64 |
| 2026-06-20 12:00 | 04:01:09.39 | +68:39:39.8 | HIP 18800 | 11.44 |
| 2026-06-21 00:00 | 04:01:12.31 | +68:39:47.9 | HIP 18800 | 11.25 |
| 2026-06-21 12:00 | 04:01:15.21 | +68:39:56.1 | HIP 18800 | 11.06 |
| 2026-06-22 00:00 | 04:01:18.10 | +68:40:04.3 | HIP 18800 | 10.87 |