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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 04:04:11.63 | +69:16:58.9 | HIP 19203 | 18.67 |
| 2026-09-20 12:00 | 04:04:10.17 | +69:17:10.4 | HIP 19203 | 18.66 |
| 2026-09-21 00:00 | 04:04:08.68 | +69:17:21.8 | HIP 19203 | 18.65 |
| 2026-09-21 12:00 | 04:04:07.17 | +69:17:33.1 | HIP 19203 | 18.64 |
| 2026-09-22 00:00 | 04:04:05.63 | +69:17:44.4 | HIP 19203 | 18.64 |
| 2026-09-22 12:00 | 04:04:04.06 | +69:17:55.6 | HIP 19203 | 18.65 |
| 2026-09-23 00:00 | 04:04:02.47 | +69:18:06.8 | HIP 19203 | 18.66 |
| 2026-09-23 12:00 | 04:04:00.85 | +69:18:17.9 | HIP 19203 | 18.68 |
| 2026-09-24 00:00 | 04:03:59.20 | +69:18:28.9 | HIP 19203 | 18.70 |
| 2026-09-24 12:00 | 04:03:57.52 | +69:18:39.8 | HIP 19203 | 18.73 |
| 2026-09-25 00:00 | 04:03:55.82 | +69:18:50.7 | HIP 19203 | 18.76 |
| 2026-09-25 12:00 | 04:03:54.09 | +69:19:01.4 | HIP 19203 | 18.80 |
| 2026-09-26 00:00 | 04:03:52.34 | +69:19:12.1 | HIP 19203 | 18.84 |
| 2026-09-26 12:00 | 04:03:50.56 | +69:19:22.8 | HIP 19203 | 18.89 |
| 2026-09-27 00:00 | 04:03:48.75 | +69:19:33.3 | HIP 19203 | 18.95 |
| 2026-09-27 12:00 | 04:03:46.92 | +69:19:43.8 | HIP 19203 | 19.01 |
| 2026-09-28 00:00 | 04:03:45.06 | +69:19:54.2 | HIP 19203 | 19.08 |
| 2026-09-28 12:00 | 04:03:43.18 | +69:20:04.5 | HIP 19203 | 19.15 |
| 2026-09-29 00:00 | 04:03:41.27 | +69:20:14.7 | HIP 19203 | 19.22 |
| 2026-09-29 12:00 | 04:03:39.34 | +69:20:24.9 | HIP 19203 | 19.31 |
| 2026-09-30 00:00 | 04:03:37.38 | +69:20:35.0 | HIP 19203 | 19.39 |
| 2026-09-30 12:00 | 04:03:35.39 | +69:20:44.9 | HIP 19203 | 19.48 |
| 2026-10-01 00:00 | 04:03:33.38 | +69:20:54.8 | HIP 19203 | 19.58 |
| 2026-10-01 12:00 | 04:03:31.34 | +69:21:04.7 | HIP 19203 | 19.68 |
| 2026-10-02 00:00 | 04:03:29.28 | +69:21:14.4 | HIP 19203 | 19.79 |
| 2026-10-02 12:00 | 04:03:27.19 | +69:21:24.0 | HIP 19203 | 19.90 |
| 2026-10-03 00:00 | 04:03:25.08 | +69:21:33.6 | HIP 19203 | 20.02 |
| 2026-10-03 12:00 | 04:03:22.95 | +69:21:43.1 | HIP 19203 | 20.14 |
| 2026-10-04 00:00 | 04:03:20.79 | +69:21:52.4 | HIP 19203 | 20.27 |
| 2026-10-04 12:00 | 04:03:18.60 | +69:22:01.7 | HIP 19203 | 20.40 |
| 2026-10-05 00:00 | 04:03:16.39 | +69:22:10.9 | HIP 19203 | 20.54 |
| 2026-10-05 12:00 | 04:03:14.16 | +69:22:20.0 | HIP 19203 | 20.68 |
| 2026-10-06 00:00 | 04:03:11.90 | +69:22:29.0 | HIP 19203 | 20.82 |
| 2026-10-06 12:00 | 04:03:09.62 | +69:22:38.0 | HIP 19203 | 20.97 |
| 2026-10-07 00:00 | 04:03:07.32 | +69:22:46.8 | HIP 19203 | 21.12 |
| 2026-10-07 12:00 | 04:03:04.99 | +69:22:55.5 | HIP 19203 | 21.28 |
| 2026-10-08 00:00 | 04:03:02.64 | +69:23:04.1 | HIP 19203 | 21.44 |
| 2026-10-08 12:00 | 04:03:00.26 | +69:23:12.7 | HIP 19203 | 21.61 |
| 2026-10-09 00:00 | 04:02:57.86 | +69:23:21.1 | HIP 19203 | 21.78 |
| 2026-10-09 12:00 | 04:02:55.44 | +69:23:29.5 | HIP 19203 | 21.95 |
| 2026-10-10 00:00 | 04:02:53.00 | +69:23:37.7 | HIP 19203 | 22.13 |
| 2026-10-10 12:00 | 04:02:50.53 | +69:23:45.8 | HIP 19203 | 22.31 |
| 2026-10-11 00:00 | 04:02:48.05 | +69:23:53.9 | HIP 19203 | 22.50 |