C/1974 C1 (Bradfield)
| 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 |
-3.5777 |
-0.850 |
| 1974-04-08 |
1974-05-07 |
+0.9937 |
+0.093 |
| 1974-05-07 |
1974-07-19 |
+1.8152 |
-0.353 |
| 1974-07-19 |
1974-09-15 |
+25.8816 |
-9.171 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
19:59:20.02 |
+10:42:18.1 |
HIP 98292 |
16.16 |
| 2026-02-03 12:00 |
19:59:21.50 |
+10:42:24.9 |
HIP 98292 |
16.51 |
| 2026-02-04 00:00 |
19:59:22.99 |
+10:42:31.8 |
HIP 98292 |
16.87 |
| 2026-02-04 12:00 |
19:59:24.47 |
+10:42:38.8 |
HIP 98292 |
17.22 |
| 2026-02-05 00:00 |
19:59:25.94 |
+10:42:45.9 |
HIP 98292 |
17.58 |
| 2026-02-05 12:00 |
19:59:27.41 |
+10:42:53.1 |
HIP 98292 |
17.93 |
| 2026-02-06 00:00 |
19:59:28.88 |
+10:43:00.3 |
HIP 98292 |
18.29 |
| 2026-02-06 12:00 |
19:59:30.34 |
+10:43:07.7 |
HIP 98292 |
18.64 |
| 2026-02-07 00:00 |
19:59:31.80 |
+10:43:15.1 |
HIP 98292 |
19.00 |
| 2026-02-07 12:00 |
19:59:33.25 |
+10:43:22.7 |
HIP 98292 |
19.35 |
| 2026-02-08 00:00 |
19:59:34.70 |
+10:43:30.3 |
HIP 98292 |
19.71 |
| 2026-02-08 12:00 |
19:59:36.15 |
+10:43:38.0 |
HIP 98292 |
20.06 |
| 2026-02-09 00:00 |
19:59:37.59 |
+10:43:45.8 |
HIP 98292 |
20.41 |
| 2026-02-09 12:00 |
19:59:39.02 |
+10:43:53.6 |
HIP 98292 |
20.77 |
| 2026-02-10 00:00 |
19:59:40.45 |
+10:44:01.6 |
HIP 98292 |
21.12 |
| 2026-02-10 12:00 |
19:59:41.88 |
+10:44:09.6 |
HIP 98292 |
21.47 |
| 2026-02-11 00:00 |
19:59:43.30 |
+10:44:17.7 |
HIP 98292 |
21.83 |
| 2026-02-11 12:00 |
19:59:44.71 |
+10:44:25.9 |
HIP 98292 |
22.18 |
| 2026-02-12 00:00 |
19:59:46.12 |
+10:44:34.2 |
HIP 98508 |
22.51 |
| 2026-02-12 12:00 |
19:59:47.52 |
+10:44:42.6 |
HIP 98508 |
22.18 |
| 2026-02-13 00:00 |
19:59:48.92 |
+10:44:51.0 |
HIP 98508 |
21.85 |
| 2026-02-13 12:00 |
19:59:50.31 |
+10:44:59.5 |
HIP 98508 |
21.53 |
| 2026-02-14 00:00 |
19:59:51.70 |
+10:45:08.1 |
HIP 98508 |
21.21 |
| 2026-02-14 12:00 |
19:59:53.08 |
+10:45:16.8 |
HIP 98508 |
20.89 |
| 2026-02-15 00:00 |
19:59:54.45 |
+10:45:25.5 |
HIP 98508 |
20.57 |
| 2026-02-15 12:00 |
19:59:55.82 |
+10:45:34.4 |
HIP 98508 |
20.25 |
| 2026-02-16 00:00 |
19:59:57.18 |
+10:45:43.3 |
HIP 98508 |
19.93 |
| 2026-02-16 12:00 |
19:59:58.54 |
+10:45:52.2 |
HIP 98508 |
19.62 |
| 2026-02-17 00:00 |
19:59:59.89 |
+10:46:01.3 |
HIP 98508 |
19.31 |
| 2026-02-17 12:00 |
20:00:01.23 |
+10:46:10.4 |
HIP 98508 |
18.99 |
| 2026-02-18 00:00 |
20:00:02.56 |
+10:46:19.6 |
HIP 98508 |
18.69 |
| 2026-02-18 12:00 |
20:00:03.89 |
+10:46:28.9 |
HIP 98508 |
18.38 |
| 2026-02-19 00:00 |
20:00:05.21 |
+10:46:38.2 |
HIP 98508 |
18.07 |
| 2026-02-19 12:00 |
20:00:06.53 |
+10:46:47.7 |
HIP 98508 |
17.77 |
| 2026-02-20 00:00 |
20:00:07.83 |
+10:46:57.1 |
HIP 98508 |
17.47 |
| 2026-02-20 12:00 |
20:00:09.13 |
+10:47:06.7 |
HIP 98508 |
17.17 |
| 2026-02-21 00:00 |
20:00:10.43 |
+10:47:16.3 |
HIP 98508 |
16.87 |
| 2026-02-21 12:00 |
20:00:11.71 |
+10:47:26.0 |
HIP 98508 |
16.57 |
| 2026-02-22 00:00 |
20:00:12.99 |
+10:47:35.7 |
HIP 98508 |
16.28 |
| 2026-02-22 12:00 |
20:00:14.26 |
+10:47:45.6 |
HIP 98508 |
15.99 |
| 2026-02-23 00:00 |
20:00:15.52 |
+10:47:55.4 |
HIP 98508 |
15.70 |
| 2026-02-23 12:00 |
20:00:16.78 |
+10:48:05.4 |
HIP 98508 |
15.41 |
| 2026-02-24 00:00 |
20:00:18.02 |
+10:48:15.4 |
HIP 98508 |
15.13 |