C/1972 E1 (Bradfield)
| 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) |
| 2026-02-03 00:00 |
08:37:51.26 |
+70:38:43.5 |
HIP 42347 |
10.90 |
| 2026-02-03 12:00 |
08:37:46.72 |
+70:38:45.3 |
HIP 42347 |
10.91 |
| 2026-02-04 00:00 |
08:37:42.17 |
+70:38:46.9 |
HIP 42347 |
10.92 |
| 2026-02-04 12:00 |
08:37:37.64 |
+70:38:48.4 |
HIP 42347 |
10.96 |
| 2026-02-05 00:00 |
08:37:33.11 |
+70:38:49.7 |
HIP 42347 |
11.01 |
| 2026-02-05 12:00 |
08:37:28.58 |
+70:38:50.8 |
HIP 42347 |
11.07 |
| 2026-02-06 00:00 |
08:37:24.07 |
+70:38:51.7 |
HIP 42347 |
11.15 |
| 2026-02-06 12:00 |
08:37:19.56 |
+70:38:52.5 |
HIP 42347 |
11.25 |
| 2026-02-07 00:00 |
08:37:15.05 |
+70:38:53.1 |
HIP 42347 |
11.36 |
| 2026-02-07 12:00 |
08:37:10.56 |
+70:38:53.6 |
HIP 42347 |
11.48 |
| 2026-02-08 00:00 |
08:37:06.07 |
+70:38:53.8 |
HIP 42347 |
11.61 |
| 2026-02-08 12:00 |
08:37:01.59 |
+70:38:53.9 |
HIP 42347 |
11.76 |
| 2026-02-09 00:00 |
08:36:57.12 |
+70:38:53.8 |
HIP 42347 |
11.92 |
| 2026-02-09 12:00 |
08:36:52.66 |
+70:38:53.6 |
HIP 42347 |
12.09 |
| 2026-02-10 00:00 |
08:36:48.21 |
+70:38:53.2 |
HIP 42347 |
12.27 |
| 2026-02-10 12:00 |
08:36:43.77 |
+70:38:52.6 |
HIP 42347 |
12.46 |
| 2026-02-11 00:00 |
08:36:39.34 |
+70:38:51.9 |
HIP 42347 |
12.66 |
| 2026-02-11 12:00 |
08:36:34.92 |
+70:38:50.9 |
HIP 42347 |
12.87 |
| 2026-02-12 00:00 |
08:36:30.51 |
+70:38:49.8 |
HIP 42347 |
13.09 |
| 2026-02-12 12:00 |
08:36:26.11 |
+70:38:48.6 |
HIP 42347 |
13.32 |
| 2026-02-13 00:00 |
08:36:21.72 |
+70:38:47.2 |
HIP 42347 |
13.55 |
| 2026-02-13 12:00 |
08:36:17.35 |
+70:38:45.6 |
HIP 42347 |
13.79 |
| 2026-02-14 00:00 |
08:36:12.99 |
+70:38:43.8 |
HIP 42347 |
14.04 |
| 2026-02-14 12:00 |
08:36:08.64 |
+70:38:41.9 |
HIP 42347 |
14.29 |
| 2026-02-15 00:00 |
08:36:04.31 |
+70:38:39.8 |
HIP 42347 |
14.55 |
| 2026-02-15 12:00 |
08:35:59.99 |
+70:38:37.5 |
HIP 42347 |
14.82 |
| 2026-02-16 00:00 |
08:35:55.68 |
+70:38:35.1 |
HIP 42347 |
15.09 |
| 2026-02-16 12:00 |
08:35:51.39 |
+70:38:32.5 |
HIP 42347 |
15.37 |
| 2026-02-17 00:00 |
08:35:47.11 |
+70:38:29.7 |
HIP 42347 |
15.65 |
| 2026-02-17 12:00 |
08:35:42.85 |
+70:38:26.8 |
HIP 42347 |
15.93 |
| 2026-02-18 00:00 |
08:35:38.60 |
+70:38:23.7 |
HIP 42347 |
16.22 |
| 2026-02-18 12:00 |
08:35:34.37 |
+70:38:20.4 |
HIP 42347 |
16.51 |
| 2026-02-19 00:00 |
08:35:30.16 |
+70:38:17.0 |
HIP 42347 |
16.80 |
| 2026-02-19 12:00 |
08:35:25.96 |
+70:38:13.4 |
HIP 42347 |
17.10 |
| 2026-02-20 00:00 |
08:35:21.78 |
+70:38:09.6 |
HIP 42347 |
17.40 |
| 2026-02-20 12:00 |
08:35:17.62 |
+70:38:05.7 |
HIP 42347 |
17.70 |
| 2026-02-21 00:00 |
08:35:13.47 |
+70:38:01.6 |
HIP 42347 |
18.01 |
| 2026-02-21 12:00 |
08:35:09.35 |
+70:37:57.3 |
HIP 42347 |
18.32 |
| 2026-02-22 00:00 |
08:35:05.24 |
+70:37:52.9 |
HIP 42347 |
18.63 |
| 2026-02-22 12:00 |
08:35:01.15 |
+70:37:48.4 |
HIP 42347 |
18.94 |
| 2026-02-23 00:00 |
08:34:57.08 |
+70:37:43.6 |
HIP 42347 |
19.25 |
| 2026-02-23 12:00 |
08:34:53.03 |
+70:37:38.7 |
HIP 42347 |
19.56 |
| 2026-02-24 00:00 |
08:34:49.00 |
+70:37:33.7 |
HIP 42347 |
19.88 |