| 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 |
9.972 |
| 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 |
+0.4532 |
-0.051 |
| 1963-01-24 |
1965-04-30 |
+1.2592 |
+0.904 |
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 |
08:33:31.02 |
+34:58:08.0 |
HIP 41820 |
23.76 |
| 2026-09-20 12:00 |
08:33:32.01 |
+34:58:09.8 |
HIP 41820 |
23.97 |
| 2026-09-21 00:00 |
08:33:32.99 |
+34:58:11.8 |
HIP 41820 |
24.17 |
| 2026-09-21 12:00 |
08:33:33.96 |
+34:58:13.8 |
HIP 41820 |
24.37 |
| 2026-09-22 00:00 |
08:33:34.92 |
+34:58:15.8 |
HIP 41820 |
24.56 |
| 2026-09-22 12:00 |
08:33:35.86 |
+34:58:18.0 |
HIP 41820 |
24.76 |
| 2026-09-23 00:00 |
08:33:36.80 |
+34:58:20.1 |
HIP 41820 |
24.95 |
| 2026-09-23 12:00 |
08:33:37.72 |
+34:58:22.4 |
HIP 41820 |
25.14 |
| 2026-09-24 00:00 |
08:33:38.64 |
+34:58:24.7 |
HIP 41820 |
25.33 |
| 2026-09-24 12:00 |
08:33:39.54 |
+34:58:27.1 |
HIP 41820 |
25.51 |
| 2026-09-25 00:00 |
08:33:40.43 |
+34:58:29.5 |
HIP 41820 |
25.69 |
| 2026-09-25 12:00 |
08:33:41.30 |
+34:58:32.0 |
HIP 41820 |
25.87 |
| 2026-09-26 00:00 |
08:33:42.17 |
+34:58:34.6 |
HIP 41820 |
26.05 |
| 2026-09-26 12:00 |
08:33:43.02 |
+34:58:37.2 |
HIP 41820 |
26.23 |
| 2026-09-27 00:00 |
08:33:43.87 |
+34:58:39.9 |
HIP 41820 |
26.40 |
| 2026-09-27 12:00 |
08:33:44.70 |
+34:58:42.7 |
HIP 41820 |
26.57 |
| 2026-09-28 00:00 |
08:33:45.51 |
+34:58:45.5 |
HIP 41820 |
26.74 |
| 2026-09-28 12:00 |
08:33:46.32 |
+34:58:48.4 |
HIP 41820 |
26.91 |
| 2026-09-29 00:00 |
08:33:47.12 |
+34:58:51.4 |
HIP 41820 |
27.07 |
| 2026-09-29 12:00 |
08:33:47.90 |
+34:58:54.4 |
HIP 41820 |
27.23 |
| 2026-09-30 00:00 |
08:33:48.67 |
+34:58:57.4 |
HIP 41820 |
27.39 |
| 2026-09-30 12:00 |
08:33:49.43 |
+34:59:00.6 |
HIP 41820 |
27.55 |
| 2026-10-01 00:00 |
08:33:50.17 |
+34:59:03.8 |
HIP 41820 |
27.70 |
| 2026-10-01 12:00 |
08:33:50.91 |
+34:59:07.0 |
HIP 41820 |
27.86 |
| 2026-10-02 00:00 |
08:33:51.63 |
+34:59:10.4 |
HIP 41820 |
28.01 |
| 2026-10-02 12:00 |
08:33:52.34 |
+34:59:13.7 |
HIP 41820 |
28.15 |
| 2026-10-03 00:00 |
08:33:53.03 |
+34:59:17.2 |
HIP 41820 |
28.30 |
| 2026-10-03 12:00 |
08:33:53.71 |
+34:59:20.7 |
HIP 41820 |
28.44 |
| 2026-10-04 00:00 |
08:33:54.38 |
+34:59:24.3 |
HIP 41820 |
28.58 |
| 2026-10-04 12:00 |
08:33:55.04 |
+34:59:27.9 |
HIP 41820 |
28.72 |
| 2026-10-05 00:00 |
08:33:55.69 |
+34:59:31.6 |
HIP 41820 |
28.85 |
| 2026-10-05 12:00 |
08:33:56.32 |
+34:59:35.4 |
HIP 41820 |
28.99 |
| 2026-10-06 00:00 |
08:33:56.94 |
+34:59:39.2 |
HIP 41820 |
29.12 |
| 2026-10-06 12:00 |
08:33:57.54 |
+34:59:43.1 |
HIP 41820 |
29.24 |
| 2026-10-07 00:00 |
08:33:58.14 |
+34:59:47.0 |
HIP 41820 |
29.37 |
| 2026-10-07 12:00 |
08:33:58.72 |
+34:59:51.0 |
HIP 41820 |
29.49 |
| 2026-10-08 00:00 |
08:33:59.28 |
+34:59:55.1 |
HIP 41820 |
29.61 |
| 2026-10-08 12:00 |
08:33:59.83 |
+34:59:59.2 |
HIP 41820 |
29.73 |
| 2026-10-09 00:00 |
08:34:00.37 |
+35:00:03.4 |
HIP 41820 |
29.84 |
| 2026-10-09 12:00 |
08:34:00.90 |
+35:00:07.6 |
HIP 41820 |
29.95 |
| 2026-10-10 00:00 |
08:34:01.41 |
+35:00:11.9 |
HIP 41820 |
30.06 |
| 2026-10-10 12:00 |
08:34:01.91 |
+35:00:16.3 |
HIP 41820 |
30.17 |
| 2026-10-11 00:00 |
08:34:02.40 |
+35:00:20.7 |
HIP 41820 |
30.28 |