| Parameter |
Value |
| Designation |
C/1974 C1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1974-03-18T08:33:10.964160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:22Z |
| Obs used |
173 |
| NEO |
- |
| M1 |
8.600 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1974-04-20.0000000 |
| e |
0.99973403 |
| q (au) |
0.503190 |
| a (au) |
1891.926449 |
| i (deg) |
61.284581 |
| Ω (om, deg) |
143.733056 |
| ω (w, deg) |
333.133285 |
| M (ma, deg) |
0.000391 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.576 + 2.404\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.576 |
| n |
2.404 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
0.989 |
| δ90 |
10.000 |
| 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 |
| 1974-02-14 |
1974-03-18 |
-1.9064 |
-0.077 |
| 1974-03-18 |
1974-04-08 |
-3.6784 |
-0.875 |
| 1974-04-08 |
1974-05-07 |
+1.3780 |
+0.127 |
| 1974-05-07 |
1974-06-13 |
-1.2851 |
+0.024 |
| 1974-06-13 |
1974-09-15 |
+11.1440 |
-3.135 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
19:58:11.45 |
+11:23:30.0 |
HIP 98252 |
4.00 |
| 2026-07-29 12:00 |
19:58:09.97 |
+11:23:24.2 |
HIP 98252 |
3.70 |
| 2026-07-30 00:00 |
19:58:08.49 |
+11:23:18.3 |
HIP 98252 |
3.41 |
| 2026-07-30 12:00 |
19:58:07.01 |
+11:23:12.4 |
HIP 98252 |
3.15 |
| 2026-07-31 00:00 |
19:58:05.53 |
+11:23:06.3 |
HIP 98252 |
2.91 |
| 2026-07-31 12:00 |
19:58:04.06 |
+11:23:00.2 |
HIP 98252 |
2.70 |
| 2026-08-01 00:00 |
19:58:02.59 |
+11:22:53.9 |
HIP 98252 |
2.54 |
| 2026-08-01 12:00 |
19:58:01.12 |
+11:22:47.5 |
HIP 98252 |
2.42 |
| 2026-08-02 00:00 |
19:57:59.65 |
+11:22:41.1 |
HIP 98252 |
2.36 |
| 2026-08-02 12:00 |
19:57:58.19 |
+11:22:34.6 |
HIP 98252 |
2.36 |
| 2026-08-03 00:00 |
19:57:56.73 |
+11:22:27.9 |
HIP 98252 |
2.42 |
| 2026-08-03 12:00 |
19:57:55.27 |
+11:22:21.2 |
HIP 98252 |
2.54 |
| 2026-08-04 00:00 |
19:57:53.82 |
+11:22:14.4 |
HIP 98252 |
2.70 |
| 2026-08-04 12:00 |
19:57:52.36 |
+11:22:07.5 |
HIP 98252 |
2.91 |
| 2026-08-05 00:00 |
19:57:50.92 |
+11:22:00.5 |
HIP 98252 |
3.15 |
| 2026-08-05 12:00 |
19:57:49.47 |
+11:21:53.4 |
HIP 98252 |
3.41 |
| 2026-08-06 00:00 |
19:57:48.03 |
+11:21:46.2 |
HIP 98252 |
3.69 |
| 2026-08-06 12:00 |
19:57:46.59 |
+11:21:39.0 |
HIP 98252 |
3.99 |
| 2026-08-07 00:00 |
19:57:45.16 |
+11:21:31.6 |
HIP 98252 |
4.30 |
| 2026-08-07 12:00 |
19:57:43.73 |
+11:21:24.2 |
HIP 98252 |
4.62 |
| 2026-08-08 00:00 |
19:57:42.30 |
+11:21:16.6 |
HIP 98252 |
4.95 |
| 2026-08-08 12:00 |
19:57:40.88 |
+11:21:09.0 |
HIP 98252 |
5.29 |
| 2026-08-09 00:00 |
19:57:39.46 |
+11:21:01.3 |
HIP 98252 |
5.62 |
| 2026-08-09 12:00 |
19:57:38.04 |
+11:20:53.5 |
HIP 98252 |
5.97 |
| 2026-08-10 00:00 |
19:57:36.63 |
+11:20:45.6 |
HIP 98252 |
6.31 |
| 2026-08-10 12:00 |
19:57:35.23 |
+11:20:37.6 |
HIP 98252 |
6.66 |
| 2026-08-11 00:00 |
19:57:33.83 |
+11:20:29.6 |
HIP 98252 |
7.01 |
| 2026-08-11 12:00 |
19:57:32.43 |
+11:20:21.4 |
HIP 98252 |
7.37 |
| 2026-08-12 00:00 |
19:57:31.04 |
+11:20:13.2 |
HIP 98252 |
7.72 |
| 2026-08-12 12:00 |
19:57:29.65 |
+11:20:04.9 |
HIP 98252 |
8.08 |
| 2026-08-13 00:00 |
19:57:28.27 |
+11:19:56.5 |
HIP 98252 |
8.43 |
| 2026-08-13 12:00 |
19:57:26.89 |
+11:19:48.0 |
HIP 98252 |
8.79 |
| 2026-08-14 00:00 |
19:57:25.52 |
+11:19:39.5 |
HIP 98252 |
9.15 |
| 2026-08-14 12:00 |
19:57:24.15 |
+11:19:30.8 |
HIP 98252 |
9.50 |
| 2026-08-15 00:00 |
19:57:22.79 |
+11:19:22.1 |
HIP 98252 |
9.86 |
| 2026-08-15 12:00 |
19:57:21.44 |
+11:19:13.3 |
HIP 98252 |
10.22 |
| 2026-08-16 00:00 |
19:57:20.09 |
+11:19:04.5 |
HIP 98252 |
10.58 |
| 2026-08-16 12:00 |
19:57:18.75 |
+11:18:55.5 |
HIP 98252 |
10.93 |
| 2026-08-17 00:00 |
19:57:17.41 |
+11:18:46.5 |
HIP 98252 |
11.29 |
| 2026-08-17 12:00 |
19:57:16.08 |
+11:18:37.4 |
HIP 98252 |
11.65 |
| 2026-08-18 00:00 |
19:57:14.75 |
+11:18:28.2 |
HIP 98252 |
12.00 |
| 2026-08-18 12:00 |
19:57:13.43 |
+11:18:18.9 |
HIP 98252 |
12.36 |
| 2026-08-19 00:00 |
19:57:12.12 |
+11:18:09.6 |
HIP 98252 |
12.71 |