| Parameter |
Value |
| Designation |
C/1972 E1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1972-03-27T16:49:37.511040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:19Z |
| Obs used |
85 |
| NEO |
- |
| M1 |
9.000 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1972-04-24.0000000 |
| e |
0.99814080 |
| q (au) |
0.927218 |
| a (au) |
498.718434 |
| i (deg) |
123.692688 |
| Ω (om, deg) |
160.299080 |
| ω (w, deg) |
257.698891 |
| M (ma, deg) |
0.002416 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.513 + 3.707\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.513 |
| n |
3.707 |
| gf |
0.999 |
| gb |
-0.500 |
| k |
0.978 |
| δ90 |
2.272 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
08:44:40.21 |
+69:38:13.0 |
HIP 42652 |
21.38 |
| 2026-09-20 12:00 |
08:44:42.88 |
+69:38:24.2 |
HIP 42652 |
21.68 |
| 2026-09-21 00:00 |
08:44:45.53 |
+69:38:35.6 |
HIP 42652 |
21.98 |
| 2026-09-21 12:00 |
08:44:48.14 |
+69:38:47.1 |
HIP 42652 |
22.28 |
| 2026-09-22 00:00 |
08:44:50.74 |
+69:38:58.7 |
HIP 42652 |
22.57 |
| 2026-09-22 12:00 |
08:44:53.30 |
+69:39:10.5 |
HIP 42652 |
22.87 |
| 2026-09-23 00:00 |
08:44:55.84 |
+69:39:22.3 |
HIP 42652 |
23.16 |
| 2026-09-23 12:00 |
08:44:58.35 |
+69:39:34.3 |
HIP 42652 |
23.46 |
| 2026-09-24 00:00 |
08:45:00.84 |
+69:39:46.4 |
HIP 42652 |
23.76 |
| 2026-09-24 12:00 |
08:45:03.30 |
+69:39:58.6 |
HIP 42652 |
24.05 |
| 2026-09-25 00:00 |
08:45:05.73 |
+69:40:10.9 |
HIP 42652 |
24.34 |
| 2026-09-25 12:00 |
08:45:08.13 |
+69:40:23.3 |
HIP 42652 |
24.64 |
| 2026-09-26 00:00 |
08:45:10.51 |
+69:40:35.9 |
HIP 42652 |
24.93 |
| 2026-09-26 12:00 |
08:45:12.86 |
+69:40:48.6 |
HIP 42652 |
25.22 |
| 2026-09-27 00:00 |
08:45:15.18 |
+69:41:01.3 |
HIP 42652 |
25.51 |
| 2026-09-27 12:00 |
08:45:17.47 |
+69:41:14.2 |
HIP 42652 |
25.80 |
| 2026-09-28 00:00 |
08:45:19.74 |
+69:41:27.2 |
HIP 42652 |
26.09 |
| 2026-09-28 12:00 |
08:45:21.98 |
+69:41:40.3 |
HIP 42652 |
26.38 |
| 2026-09-29 00:00 |
08:45:24.18 |
+69:41:53.5 |
HIP 42652 |
26.67 |
| 2026-09-29 12:00 |
08:45:26.36 |
+69:42:06.9 |
HIP 42652 |
26.96 |
| 2026-09-30 00:00 |
08:45:28.51 |
+69:42:20.3 |
HIP 42652 |
27.25 |
| 2026-09-30 12:00 |
08:45:30.64 |
+69:42:33.8 |
HIP 42652 |
27.54 |
| 2026-10-01 00:00 |
08:45:32.73 |
+69:42:47.5 |
HIP 42652 |
27.82 |
| 2026-10-01 12:00 |
08:45:34.79 |
+69:43:01.3 |
HIP 42652 |
28.11 |
| 2026-10-02 00:00 |
08:45:36.83 |
+69:43:15.1 |
HIP 42652 |
28.39 |
| 2026-10-02 12:00 |
08:45:38.83 |
+69:43:29.1 |
HIP 42652 |
28.68 |
| 2026-10-03 00:00 |
08:45:40.80 |
+69:43:43.2 |
HIP 42652 |
28.96 |
| 2026-10-03 12:00 |
08:45:42.75 |
+69:43:57.3 |
HIP 42652 |
29.24 |
| 2026-10-04 00:00 |
08:45:44.66 |
+69:44:11.6 |
HIP 42779 |
29.28 |
| 2026-10-04 12:00 |
08:45:46.54 |
+69:44:26.0 |
HIP 42779 |
29.15 |
| 2026-10-05 00:00 |
08:45:48.39 |
+69:44:40.5 |
HIP 42779 |
29.02 |
| 2026-10-05 12:00 |
08:45:50.21 |
+69:44:55.1 |
HIP 42779 |
28.88 |
| 2026-10-06 00:00 |
08:45:52.00 |
+69:45:09.7 |
HIP 42779 |
28.75 |
| 2026-10-06 12:00 |
08:45:53.76 |
+69:45:24.5 |
HIP 42779 |
28.61 |
| 2026-10-07 00:00 |
08:45:55.48 |
+69:45:39.4 |
HIP 42779 |
28.48 |
| 2026-10-07 12:00 |
08:45:57.18 |
+69:45:54.4 |
HIP 42779 |
28.34 |
| 2026-10-08 00:00 |
08:45:58.84 |
+69:46:09.4 |
HIP 42779 |
28.21 |
| 2026-10-08 12:00 |
08:46:00.47 |
+69:46:24.6 |
HIP 42779 |
28.07 |
| 2026-10-09 00:00 |
08:46:02.07 |
+69:46:39.8 |
HIP 42779 |
27.93 |
| 2026-10-09 12:00 |
08:46:03.63 |
+69:46:55.2 |
HIP 42779 |
27.80 |
| 2026-10-10 00:00 |
08:46:05.17 |
+69:47:10.6 |
HIP 42779 |
27.66 |
| 2026-10-10 12:00 |
08:46:06.67 |
+69:47:26.1 |
HIP 42779 |
27.52 |
| 2026-10-11 00:00 |
08:46:08.13 |
+69:47:41.8 |
HIP 42779 |
27.38 |