C/1961 R1 (Humason)
| Parameter |
Value |
| Designation |
C/1961 R1 (Humason) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1962-12-10T05:16:13.828800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:14Z |
| Obs used |
80 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1963-05-12.0000000 |
| e |
0.98961410 |
| q (au) |
2.133470 |
| a (au) |
205.419821 |
| i (deg) |
153.277926 |
| Ω (om, deg) |
155.439541 |
| ω (w, deg) |
233.562038 |
| M (ma, deg) |
0.051146 |
Magnitude
Scatter + Global Linear
$$
M_a = (0.444 + 5.517\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
0.444 |
| n |
5.517 |
| gf |
1.000 |
| gb |
-0.889 |
| k |
0.999 |
| δ90 |
9.971 |
| 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 |
| 1961-09-06 |
1962-12-03 |
+0.4530 |
-0.051 |
| 1963-01-24 |
1964-05-22 |
+7.5657 |
-1.879 |
| 1964-05-22 |
1965-04-30 |
-17.0329 |
+15.601 |
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 |
08:30:45.78 |
+35:23:28.4 |
HIP 41770 |
4.16 |
| 2026-02-03 12:00 |
08:30:44.02 |
+35:23:32.9 |
HIP 41770 |
4.52 |
| 2026-02-04 00:00 |
08:30:42.26 |
+35:23:37.3 |
HIP 41770 |
4.87 |
| 2026-02-04 12:00 |
08:30:40.51 |
+35:23:41.7 |
HIP 41770 |
5.23 |
| 2026-02-05 00:00 |
08:30:38.75 |
+35:23:46.0 |
HIP 41770 |
5.59 |
| 2026-02-05 12:00 |
08:30:37.00 |
+35:23:50.3 |
HIP 41770 |
5.95 |
| 2026-02-06 00:00 |
08:30:35.25 |
+35:23:54.4 |
HIP 41770 |
6.31 |
| 2026-02-06 12:00 |
08:30:33.51 |
+35:23:58.5 |
HIP 41770 |
6.67 |
| 2026-02-07 00:00 |
08:30:31.77 |
+35:24:02.6 |
HIP 41770 |
7.03 |
| 2026-02-07 12:00 |
08:30:30.03 |
+35:24:06.6 |
HIP 41770 |
7.38 |
| 2026-02-08 00:00 |
08:30:28.29 |
+35:24:10.5 |
HIP 41770 |
7.74 |
| 2026-02-08 12:00 |
08:30:26.56 |
+35:24:14.4 |
HIP 41770 |
8.09 |
| 2026-02-09 00:00 |
08:30:24.83 |
+35:24:18.1 |
HIP 41770 |
8.45 |
| 2026-02-09 12:00 |
08:30:23.11 |
+35:24:21.9 |
HIP 41770 |
8.80 |
| 2026-02-10 00:00 |
08:30:21.39 |
+35:24:25.5 |
HIP 41770 |
9.16 |
| 2026-02-10 12:00 |
08:30:19.67 |
+35:24:29.1 |
HIP 41770 |
9.51 |
| 2026-02-11 00:00 |
08:30:17.96 |
+35:24:32.7 |
HIP 41770 |
9.86 |
| 2026-02-11 12:00 |
08:30:16.26 |
+35:24:36.1 |
HIP 41770 |
10.21 |
| 2026-02-12 00:00 |
08:30:14.55 |
+35:24:39.5 |
HIP 41770 |
10.56 |
| 2026-02-12 12:00 |
08:30:12.86 |
+35:24:42.8 |
HIP 41770 |
10.91 |
| 2026-02-13 00:00 |
08:30:11.16 |
+35:24:46.1 |
HIP 41770 |
11.25 |
| 2026-02-13 12:00 |
08:30:09.48 |
+35:24:49.3 |
HIP 41770 |
11.60 |
| 2026-02-14 00:00 |
08:30:07.79 |
+35:24:52.4 |
HIP 41770 |
11.94 |
| 2026-02-14 12:00 |
08:30:06.12 |
+35:24:55.5 |
HIP 41770 |
12.29 |
| 2026-02-15 00:00 |
08:30:04.44 |
+35:24:58.5 |
HIP 41770 |
12.63 |
| 2026-02-15 12:00 |
08:30:02.78 |
+35:25:01.4 |
HIP 41770 |
12.97 |
| 2026-02-16 00:00 |
08:30:01.12 |
+35:25:04.2 |
HIP 41770 |
13.31 |
| 2026-02-16 12:00 |
08:29:59.46 |
+35:25:07.0 |
HIP 41770 |
13.65 |
| 2026-02-17 00:00 |
08:29:57.81 |
+35:25:09.7 |
HIP 41770 |
13.98 |
| 2026-02-17 12:00 |
08:29:56.17 |
+35:25:12.4 |
HIP 41770 |
14.32 |
| 2026-02-18 00:00 |
08:29:54.53 |
+35:25:15.0 |
HIP 41770 |
14.65 |
| 2026-02-18 12:00 |
08:29:52.90 |
+35:25:17.5 |
HIP 41770 |
14.99 |
| 2026-02-19 00:00 |
08:29:51.28 |
+35:25:19.9 |
HIP 41770 |
15.32 |
| 2026-02-19 12:00 |
08:29:49.66 |
+35:25:22.3 |
HIP 41770 |
15.65 |
| 2026-02-20 00:00 |
08:29:48.05 |
+35:25:24.6 |
HIP 41770 |
15.98 |
| 2026-02-20 12:00 |
08:29:46.45 |
+35:25:26.8 |
HIP 41770 |
16.30 |
| 2026-02-21 00:00 |
08:29:44.85 |
+35:25:29.0 |
HIP 41770 |
16.63 |
| 2026-02-21 12:00 |
08:29:43.26 |
+35:25:31.0 |
HIP 41770 |
16.95 |
| 2026-02-22 00:00 |
08:29:41.68 |
+35:25:33.1 |
HIP 41770 |
17.27 |
| 2026-02-22 12:00 |
08:29:40.10 |
+35:25:35.0 |
HIP 41770 |
17.59 |
| 2026-02-23 00:00 |
08:29:38.53 |
+35:25:36.9 |
HIP 41770 |
17.91 |
| 2026-02-23 12:00 |
08:29:36.97 |
+35:25:38.7 |
HIP 41770 |
18.23 |
| 2026-02-24 00:00 |
08:29:35.42 |
+35:25:40.4 |
HIP 41770 |
18.54 |