| 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 |
1965-04-30 |
+1.2589 |
+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) |
| 2026-05-12 00:00 |
08:27:56.67 |
+35:17:43.7 |
HIP 41554 |
17.53 |
| 2026-05-12 12:00 |
08:27:57.09 |
+35:17:37.0 |
HIP 41554 |
17.40 |
| 2026-05-13 00:00 |
08:27:57.53 |
+35:17:30.3 |
HIP 41554 |
17.26 |
| 2026-05-13 12:00 |
08:27:57.98 |
+35:17:23.6 |
HIP 41554 |
17.13 |
| 2026-05-14 00:00 |
08:27:58.44 |
+35:17:16.9 |
HIP 41554 |
16.99 |
| 2026-05-14 12:00 |
08:27:58.92 |
+35:17:10.1 |
HIP 41554 |
16.86 |
| 2026-05-15 00:00 |
08:27:59.41 |
+35:17:03.3 |
HIP 41554 |
16.72 |
| 2026-05-15 12:00 |
08:27:59.91 |
+35:16:56.5 |
HIP 41554 |
16.58 |
| 2026-05-16 00:00 |
08:28:00.43 |
+35:16:49.7 |
HIP 41554 |
16.44 |
| 2026-05-16 12:00 |
08:28:00.96 |
+35:16:42.8 |
HIP 41554 |
16.30 |
| 2026-05-17 00:00 |
08:28:01.50 |
+35:16:35.9 |
HIP 41554 |
16.16 |
| 2026-05-17 12:00 |
08:28:02.06 |
+35:16:29.0 |
HIP 41554 |
16.02 |
| 2026-05-18 00:00 |
08:28:02.63 |
+35:16:22.1 |
HIP 41554 |
15.88 |
| 2026-05-18 12:00 |
08:28:03.21 |
+35:16:15.2 |
HIP 41554 |
15.74 |
| 2026-05-19 00:00 |
08:28:03.81 |
+35:16:08.3 |
HIP 41554 |
15.60 |
| 2026-05-19 12:00 |
08:28:04.41 |
+35:16:01.3 |
HIP 41554 |
15.45 |
| 2026-05-20 00:00 |
08:28:05.04 |
+35:15:54.3 |
HIP 41554 |
15.31 |
| 2026-05-20 12:00 |
08:28:05.67 |
+35:15:47.3 |
HIP 41554 |
15.17 |
| 2026-05-21 00:00 |
08:28:06.32 |
+35:15:40.3 |
HIP 41554 |
15.02 |
| 2026-05-21 12:00 |
08:28:06.98 |
+35:15:33.3 |
HIP 41554 |
14.88 |
| 2026-05-22 00:00 |
08:28:07.65 |
+35:15:26.2 |
HIP 41554 |
14.73 |
| 2026-05-22 12:00 |
08:28:08.33 |
+35:15:19.2 |
HIP 41554 |
14.59 |
| 2026-05-23 00:00 |
08:28:09.03 |
+35:15:12.1 |
HIP 41554 |
14.45 |
| 2026-05-23 12:00 |
08:28:09.74 |
+35:15:05.0 |
HIP 41554 |
14.30 |
| 2026-05-24 00:00 |
08:28:10.46 |
+35:14:57.9 |
HIP 41554 |
14.16 |
| 2026-05-24 12:00 |
08:28:11.20 |
+35:14:50.8 |
HIP 41554 |
14.02 |
| 2026-05-25 00:00 |
08:28:11.94 |
+35:14:43.7 |
HIP 41554 |
13.87 |
| 2026-05-25 12:00 |
08:28:12.70 |
+35:14:36.6 |
HIP 41554 |
13.73 |
| 2026-05-26 00:00 |
08:28:13.47 |
+35:14:29.5 |
HIP 41554 |
13.59 |
| 2026-05-26 12:00 |
08:28:14.26 |
+35:14:22.3 |
HIP 41554 |
13.45 |
| 2026-05-27 00:00 |
08:28:15.05 |
+35:14:15.2 |
HIP 41554 |
13.31 |
| 2026-05-27 12:00 |
08:28:15.86 |
+35:14:08.0 |
HIP 41554 |
13.18 |
| 2026-05-28 00:00 |
08:28:16.68 |
+35:14:00.8 |
HIP 41554 |
13.04 |
| 2026-05-28 12:00 |
08:28:17.51 |
+35:13:53.6 |
HIP 41554 |
12.90 |
| 2026-05-29 00:00 |
08:28:18.35 |
+35:13:46.5 |
HIP 41554 |
12.77 |
| 2026-05-29 12:00 |
08:28:19.20 |
+35:13:39.3 |
HIP 41554 |
12.64 |
| 2026-05-30 00:00 |
08:28:20.07 |
+35:13:32.1 |
HIP 41554 |
12.51 |
| 2026-05-30 12:00 |
08:28:20.94 |
+35:13:24.9 |
HIP 41554 |
12.39 |
| 2026-05-31 00:00 |
08:28:21.83 |
+35:13:17.6 |
HIP 41554 |
12.26 |
| 2026-05-31 12:00 |
08:28:22.73 |
+35:13:10.4 |
HIP 41554 |
12.14 |
| 2026-06-01 00:00 |
08:28:23.64 |
+35:13:03.2 |
HIP 41554 |
12.02 |
| 2026-06-01 12:00 |
08:28:24.56 |
+35:12:56.0 |
HIP 41554 |
11.90 |
| 2026-06-02 00:00 |
08:28:25.50 |
+35:12:48.8 |
HIP 41554 |
11.79 |