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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 03:56:58.55 | +68:34:22.3 | HIP 18574 | 15.64 |
| 2026-05-12 12:00 | 03:57:01.76 | +68:34:22.0 | HIP 18574 | 15.47 |
| 2026-05-13 00:00 | 03:57:04.97 | +68:34:21.9 | HIP 18574 | 15.31 |
| 2026-05-13 12:00 | 03:57:08.19 | +68:34:21.8 | HIP 18574 | 15.16 |
| 2026-05-14 00:00 | 03:57:11.42 | +68:34:21.9 | HIP 18574 | 15.01 |
| 2026-05-14 12:00 | 03:57:14.65 | +68:34:22.1 | HIP 18574 | 14.86 |
| 2026-05-15 00:00 | 03:57:17.88 | +68:34:22.4 | HIP 18574 | 14.72 |
| 2026-05-15 12:00 | 03:57:21.12 | +68:34:22.8 | HIP 18574 | 14.59 |
| 2026-05-16 00:00 | 03:57:24.36 | +68:34:23.4 | HIP 18574 | 14.46 |
| 2026-05-16 12:00 | 03:57:27.60 | +68:34:24.0 | HIP 18574 | 14.35 |
| 2026-05-17 00:00 | 03:57:30.84 | +68:34:24.8 | HIP 18574 | 14.23 |
| 2026-05-17 12:00 | 03:57:34.09 | +68:34:25.7 | HIP 18574 | 14.13 |
| 2026-05-18 00:00 | 03:57:37.34 | +68:34:26.7 | HIP 18574 | 14.03 |
| 2026-05-18 12:00 | 03:57:40.60 | +68:34:27.8 | HIP 18574 | 13.94 |
| 2026-05-19 00:00 | 03:57:43.85 | +68:34:29.0 | HIP 18574 | 13.86 |
| 2026-05-19 12:00 | 03:57:47.11 | +68:34:30.4 | HIP 18574 | 13.78 |
| 2026-05-20 00:00 | 03:57:50.37 | +68:34:31.8 | HIP 18574 | 13.71 |
| 2026-05-20 12:00 | 03:57:53.62 | +68:34:33.4 | HIP 18574 | 13.65 |
| 2026-05-21 00:00 | 03:57:56.88 | +68:34:35.1 | HIP 18574 | 13.60 |
| 2026-05-21 12:00 | 03:58:00.15 | +68:34:36.9 | HIP 18574 | 13.56 |
| 2026-05-22 00:00 | 03:58:03.41 | +68:34:38.8 | HIP 18574 | 13.53 |
| 2026-05-22 12:00 | 03:58:06.67 | +68:34:40.8 | HIP 18574 | 13.50 |
| 2026-05-23 00:00 | 03:58:09.93 | +68:34:42.9 | HIP 18574 | 13.48 |
| 2026-05-23 12:00 | 03:58:13.19 | +68:34:45.1 | HIP 18574 | 13.47 |
| 2026-05-24 00:00 | 03:58:16.45 | +68:34:47.5 | HIP 18574 | 13.47 |
| 2026-05-24 12:00 | 03:58:19.72 | +68:34:50.0 | HIP 18574 | 13.48 |
| 2026-05-25 00:00 | 03:58:22.98 | +68:34:52.5 | HIP 18574 | 13.50 |
| 2026-05-25 12:00 | 03:58:26.23 | +68:34:55.2 | HIP 18574 | 13.53 |
| 2026-05-26 00:00 | 03:58:29.49 | +68:34:58.0 | HIP 18574 | 13.56 |
| 2026-05-26 12:00 | 03:58:32.75 | +68:35:00.9 | HIP 18574 | 13.60 |
| 2026-05-27 00:00 | 03:58:36.00 | +68:35:03.9 | HIP 18574 | 13.65 |
| 2026-05-27 12:00 | 03:58:39.26 | +68:35:07.1 | HIP 18574 | 13.71 |
| 2026-05-28 00:00 | 03:58:42.51 | +68:35:10.3 | HIP 18574 | 13.78 |
| 2026-05-28 12:00 | 03:58:45.76 | +68:35:13.6 | HIP 18574 | 13.86 |
| 2026-05-29 00:00 | 03:58:49.01 | +68:35:17.1 | HIP 18574 | 13.94 |
| 2026-05-29 12:00 | 03:58:52.25 | +68:35:20.6 | HIP 18574 | 14.03 |
| 2026-05-30 00:00 | 03:58:55.49 | +68:35:24.3 | HIP 18574 | 14.13 |
| 2026-05-30 12:00 | 03:58:58.73 | +68:35:28.1 | HIP 18574 | 14.24 |
| 2026-05-31 00:00 | 03:59:01.97 | +68:35:32.0 | HIP 18574 | 14.35 |
| 2026-05-31 12:00 | 03:59:05.20 | +68:35:36.0 | HIP 18574 | 14.47 |
| 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 |