C/1980 Y2 (Panther)
| Parameter |
Value |
| Designation |
C/1980 Y2 (Panther) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1981-01-27T07:35:59.709120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:29Z |
| Obs used |
200 |
| NEO |
- |
| M1 |
6.800 |
| K1 |
6.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1981-02-26.0000000 |
| e |
0.99865714 |
| q (au) |
1.657187 |
| a (au) |
1234.075622 |
| i (deg) |
82.646128 |
| Ω (om, deg) |
332.000700 |
| ω (w, deg) |
105.597962 |
| M (ma, deg) |
0.000675 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.548 + 4.217\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.548 |
| n |
4.217 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.863 |
| δ90 |
1.000 |
| 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 |
| 1980-10-27 |
1981-01-26 |
+21.4786 |
-4.799 |
| 1981-01-27 |
1981-06-03 |
-0.3491 |
+0.057 |
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 |
07:01:06.77 |
-72:07:35.7 |
HIP 34035 |
13.94 |
| 2026-02-03 12:00 |
07:01:01.77 |
-72:07:23.5 |
HIP 34035 |
14.15 |
| 2026-02-04 00:00 |
07:00:56.79 |
-72:07:11.1 |
HIP 34035 |
14.38 |
| 2026-02-04 12:00 |
07:00:51.84 |
-72:06:58.5 |
HIP 34035 |
14.61 |
| 2026-02-05 00:00 |
07:00:46.91 |
-72:06:45.7 |
HIP 34035 |
14.84 |
| 2026-02-05 12:00 |
07:00:42.01 |
-72:06:32.6 |
HIP 34035 |
15.09 |
| 2026-02-06 00:00 |
07:00:37.14 |
-72:06:19.4 |
HIP 34035 |
15.33 |
| 2026-02-06 12:00 |
07:00:32.30 |
-72:06:06.0 |
HIP 34035 |
15.58 |
| 2026-02-07 00:00 |
07:00:27.49 |
-72:05:52.4 |
HIP 34035 |
15.84 |
| 2026-02-07 12:00 |
07:00:22.70 |
-72:05:38.6 |
HIP 33427 |
15.68 |
| 2026-02-08 00:00 |
07:00:17.95 |
-72:05:24.6 |
HIP 33427 |
15.28 |
| 2026-02-08 12:00 |
07:00:13.23 |
-72:05:10.4 |
HIP 33427 |
14.87 |
| 2026-02-09 00:00 |
07:00:08.53 |
-72:04:56.0 |
HIP 33427 |
14.47 |
| 2026-02-09 12:00 |
07:00:03.87 |
-72:04:41.5 |
HIP 33427 |
14.08 |
| 2026-02-10 00:00 |
06:59:59.24 |
-72:04:26.7 |
HIP 33427 |
13.69 |
| 2026-02-10 12:00 |
06:59:54.64 |
-72:04:11.7 |
HIP 33427 |
13.30 |
| 2026-02-11 00:00 |
06:59:50.07 |
-72:03:56.6 |
HIP 33427 |
12.92 |
| 2026-02-11 12:00 |
06:59:45.53 |
-72:03:41.3 |
HIP 33427 |
12.54 |
| 2026-02-12 00:00 |
06:59:41.03 |
-72:03:25.7 |
HIP 33427 |
12.17 |
| 2026-02-12 12:00 |
06:59:36.56 |
-72:03:10.0 |
HIP 33427 |
11.80 |
| 2026-02-13 00:00 |
06:59:32.12 |
-72:02:54.2 |
HIP 33427 |
11.44 |
| 2026-02-13 12:00 |
06:59:27.72 |
-72:02:38.1 |
HIP 33427 |
11.09 |
| 2026-02-14 00:00 |
06:59:23.34 |
-72:02:21.8 |
HIP 33427 |
10.75 |
| 2026-02-14 12:00 |
06:59:19.01 |
-72:02:05.4 |
HIP 33427 |
10.41 |
| 2026-02-15 00:00 |
06:59:14.71 |
-72:01:48.8 |
HIP 33427 |
10.09 |
| 2026-02-15 12:00 |
06:59:10.44 |
-72:01:32.0 |
HIP 33427 |
9.78 |
| 2026-02-16 00:00 |
06:59:06.21 |
-72:01:15.1 |
HIP 33427 |
9.48 |
| 2026-02-16 12:00 |
06:59:02.02 |
-72:00:58.0 |
HIP 33427 |
9.19 |
| 2026-02-17 00:00 |
06:58:57.86 |
-72:00:40.7 |
HIP 33427 |
8.92 |
| 2026-02-17 12:00 |
06:58:53.74 |
-72:00:23.2 |
HIP 33427 |
8.66 |
| 2026-02-18 00:00 |
06:58:49.65 |
-72:00:05.6 |
HIP 33427 |
8.42 |
| 2026-02-18 12:00 |
06:58:45.60 |
-71:59:47.8 |
HIP 33427 |
8.20 |
| 2026-02-19 00:00 |
06:58:41.59 |
-71:59:29.8 |
HIP 33427 |
8.00 |
| 2026-02-19 12:00 |
06:58:37.62 |
-71:59:11.7 |
HIP 33427 |
7.83 |
| 2026-02-20 00:00 |
06:58:33.68 |
-71:58:53.4 |
HIP 33427 |
7.67 |
| 2026-02-20 12:00 |
06:58:29.78 |
-71:58:35.0 |
HIP 33427 |
7.55 |
| 2026-02-21 00:00 |
06:58:25.92 |
-71:58:16.4 |
HIP 33427 |
7.45 |
| 2026-02-21 12:00 |
06:58:22.10 |
-71:57:57.6 |
HIP 33427 |
7.37 |
| 2026-02-22 00:00 |
06:58:18.32 |
-71:57:38.7 |
HIP 33427 |
7.33 |
| 2026-02-22 12:00 |
06:58:14.58 |
-71:57:19.7 |
HIP 33427 |
7.31 |
| 2026-02-23 00:00 |
06:58:10.88 |
-71:57:00.5 |
HIP 33427 |
7.32 |
| 2026-02-23 12:00 |
06:58:07.22 |
-71:56:41.1 |
HIP 33427 |
7.37 |
| 2026-02-24 00:00 |
06:58:03.59 |
-71:56:21.6 |
HIP 33427 |
7.44 |