C/1979 Y1 (Bradfield)
| Parameter |
Value |
| Designation |
C/1979 Y1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1979-12-21T14:38:01.069440Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:29Z |
| Obs used |
127 |
| NEO |
- |
| M1 |
8.500 |
| K1 |
14.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1980-01-25.0000000 |
| e |
0.98803814 |
| q (au) |
0.545301 |
| a (au) |
45.586646 |
| i (deg) |
148.602533 |
| Ω (om, deg) |
103.215535 |
| ω (w, deg) |
257.609730 |
| M (ma, deg) |
0.110124 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.331 + 4.383\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.331 |
| n |
4.383 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.800 |
| 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 |
| 1979-12-26 |
1980-01-04 |
-10.3165 |
-2.880 |
| 1980-01-04 |
1980-01-17 |
+20.4042 |
+3.298 |
| 1980-01-17 |
1980-01-25 |
-11.5672 |
+0.125 |
| 1980-01-25 |
1980-03-02 |
-3.9664 |
+0.215 |
| 1980-03-02 |
1980-03-17 |
-5.5222 |
+0.290 |
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 |
01:16:52.41 |
+40:09:14.0 |
HIP 6120 |
19.90 |
| 2026-02-03 12:00 |
01:16:53.31 |
+40:09:02.8 |
HIP 6120 |
19.77 |
| 2026-02-04 00:00 |
01:16:54.23 |
+40:08:51.8 |
HIP 6120 |
19.64 |
| 2026-02-04 12:00 |
01:16:55.18 |
+40:08:40.9 |
HIP 6120 |
19.51 |
| 2026-02-05 00:00 |
01:16:56.14 |
+40:08:30.2 |
HIP 6120 |
19.37 |
| 2026-02-05 12:00 |
01:16:57.12 |
+40:08:19.6 |
HIP 6120 |
19.24 |
| 2026-02-06 00:00 |
01:16:58.12 |
+40:08:09.1 |
HIP 6120 |
19.10 |
| 2026-02-06 12:00 |
01:16:59.14 |
+40:07:58.7 |
HIP 6120 |
18.97 |
| 2026-02-07 00:00 |
01:17:00.18 |
+40:07:48.5 |
HIP 6120 |
18.83 |
| 2026-02-07 12:00 |
01:17:01.23 |
+40:07:38.5 |
HIP 6120 |
18.69 |
| 2026-02-08 00:00 |
01:17:02.30 |
+40:07:28.6 |
HIP 6120 |
18.55 |
| 2026-02-08 12:00 |
01:17:03.40 |
+40:07:18.8 |
HIP 6120 |
18.40 |
| 2026-02-09 00:00 |
01:17:04.51 |
+40:07:09.1 |
HIP 6120 |
18.26 |
| 2026-02-09 12:00 |
01:17:05.64 |
+40:06:59.6 |
HIP 6120 |
18.11 |
| 2026-02-10 00:00 |
01:17:06.78 |
+40:06:50.3 |
HIP 6120 |
17.97 |
| 2026-02-10 12:00 |
01:17:07.95 |
+40:06:41.1 |
HIP 6120 |
17.82 |
| 2026-02-11 00:00 |
01:17:09.13 |
+40:06:32.0 |
HIP 6120 |
17.67 |
| 2026-02-11 12:00 |
01:17:10.33 |
+40:06:23.1 |
HIP 6120 |
17.52 |
| 2026-02-12 00:00 |
01:17:11.55 |
+40:06:14.3 |
HIP 6120 |
17.36 |
| 2026-02-12 12:00 |
01:17:12.79 |
+40:06:05.7 |
HIP 6120 |
17.21 |
| 2026-02-13 00:00 |
01:17:14.04 |
+40:05:57.2 |
HIP 6120 |
17.06 |
| 2026-02-13 12:00 |
01:17:15.31 |
+40:05:48.9 |
HIP 6120 |
16.90 |
| 2026-02-14 00:00 |
01:17:16.60 |
+40:05:40.7 |
HIP 6120 |
16.75 |
| 2026-02-14 12:00 |
01:17:17.91 |
+40:05:32.6 |
HIP 6120 |
16.59 |
| 2026-02-15 00:00 |
01:17:19.23 |
+40:05:24.8 |
HIP 6120 |
16.43 |
| 2026-02-15 12:00 |
01:17:20.57 |
+40:05:17.0 |
HIP 6120 |
16.27 |
| 2026-02-16 00:00 |
01:17:21.93 |
+40:05:09.4 |
HIP 6120 |
16.12 |
| 2026-02-16 12:00 |
01:17:23.30 |
+40:05:02.0 |
HIP 6120 |
15.96 |
| 2026-02-17 00:00 |
01:17:24.69 |
+40:04:54.7 |
HIP 6120 |
15.80 |
| 2026-02-17 12:00 |
01:17:26.10 |
+40:04:47.6 |
HIP 6120 |
15.64 |
| 2026-02-18 00:00 |
01:17:27.52 |
+40:04:40.6 |
HIP 6120 |
15.48 |
| 2026-02-18 12:00 |
01:17:28.96 |
+40:04:33.7 |
HIP 6120 |
15.32 |
| 2026-02-19 00:00 |
01:17:30.42 |
+40:04:27.1 |
HIP 6120 |
15.16 |
| 2026-02-19 12:00 |
01:17:31.89 |
+40:04:20.5 |
HIP 6120 |
15.00 |
| 2026-02-20 00:00 |
01:17:33.37 |
+40:04:14.2 |
HIP 6120 |
14.84 |
| 2026-02-20 12:00 |
01:17:34.88 |
+40:04:07.9 |
HIP 6120 |
14.68 |
| 2026-02-21 00:00 |
01:17:36.40 |
+40:04:01.9 |
HIP 6120 |
14.53 |
| 2026-02-21 12:00 |
01:17:37.93 |
+40:03:56.0 |
HIP 6120 |
14.37 |
| 2026-02-22 00:00 |
01:17:39.48 |
+40:03:50.2 |
HIP 6120 |
14.22 |
| 2026-02-22 12:00 |
01:17:41.04 |
+40:03:44.6 |
HIP 6120 |
14.06 |
| 2026-02-23 00:00 |
01:17:42.62 |
+40:03:39.1 |
HIP 6120 |
13.91 |
| 2026-02-23 12:00 |
01:17:44.22 |
+40:03:33.8 |
HIP 6120 |
13.76 |
| 2026-02-24 00:00 |
01:17:45.83 |
+40:03:28.7 |
HIP 6120 |
13.61 |