| Parameter |
Value |
| Designation |
273P/Pons-Gambart |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-12-19T16:06:04.144320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:12Z |
| Obs used |
1140 |
| NEO |
Yes |
| M1 |
11.300 |
| K1 |
8.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-03-18.0000000 |
| e |
0.97532437 |
| q (au) |
0.810159 |
| a (au) |
32.832346 |
| i (deg) |
136.396031 |
| Ω (om, deg) |
320.431172 |
| ω (w, deg) |
20.191912 |
| M (ma, deg) |
0.462759 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.697 + 5.779\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.697 |
| n |
5.779 |
| gf |
1.000 |
| gb |
-0.949 |
| 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 |
| 2012-12-22 |
2013-01-27 |
-8.2349 |
-1.482 |
| 2013-01-27 |
2013-02-11 |
+1.7959 |
-1.599 |
| 2013-02-11 |
2013-03-04 |
+15.9199 |
-2.714 |
| 2013-03-04 |
2013-04-29 |
+2.7105 |
-0.831 |
| 2013-04-29 |
2014-04-04 |
-2.5470 |
+0.557 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
09:05:19.54 |
+12:48:25.7 |
HIP 44581 |
32.63 |
| 2026-03-26 12:00 |
09:05:16.61 |
+12:48:39.8 |
HIP 44581 |
32.29 |
| 2026-03-27 00:00 |
09:05:13.71 |
+12:48:53.8 |
HIP 44581 |
31.97 |
| 2026-03-27 12:00 |
09:05:10.85 |
+12:49:07.7 |
HIP 44581 |
31.66 |
| 2026-03-28 00:00 |
09:05:08.01 |
+12:49:21.5 |
HIP 44581 |
31.37 |
| 2026-03-28 12:00 |
09:05:05.21 |
+12:49:35.1 |
HIP 44581 |
31.10 |
| 2026-03-29 00:00 |
09:05:02.44 |
+12:49:48.6 |
HIP 44581 |
30.85 |
| 2026-03-29 12:00 |
09:04:59.70 |
+12:50:02.0 |
HIP 44581 |
30.61 |
| 2026-03-30 00:00 |
09:04:56.99 |
+12:50:15.3 |
HIP 44581 |
30.39 |
| 2026-03-30 12:00 |
09:04:54.32 |
+12:50:28.5 |
HIP 44581 |
30.18 |
| 2026-03-31 00:00 |
09:04:51.67 |
+12:50:41.5 |
HIP 44581 |
29.99 |
| 2026-03-31 12:00 |
09:04:49.06 |
+12:50:54.4 |
HIP 44581 |
29.81 |
| 2026-04-01 00:00 |
09:04:46.49 |
+12:51:07.2 |
HIP 44581 |
29.66 |
| 2026-04-01 12:00 |
09:04:43.94 |
+12:51:19.8 |
HIP 44581 |
29.51 |
| 2026-04-02 00:00 |
09:04:41.43 |
+12:51:32.4 |
HIP 44581 |
29.38 |
| 2026-04-02 12:00 |
09:04:38.95 |
+12:51:44.8 |
HIP 44581 |
29.27 |
| 2026-04-03 00:00 |
09:04:36.51 |
+12:51:57.1 |
HIP 44581 |
29.17 |
| 2026-04-03 12:00 |
09:04:34.09 |
+12:52:09.2 |
HIP 44581 |
29.08 |
| 2026-04-04 00:00 |
09:04:31.71 |
+12:52:21.2 |
HIP 44581 |
29.01 |
| 2026-04-04 12:00 |
09:04:29.37 |
+12:52:33.1 |
HIP 44581 |
28.95 |
| 2026-04-05 00:00 |
09:04:27.06 |
+12:52:44.9 |
HIP 44581 |
28.90 |
| 2026-04-05 12:00 |
09:04:24.78 |
+12:52:56.5 |
HIP 44581 |
28.86 |
| 2026-04-06 00:00 |
09:04:22.53 |
+12:53:08.0 |
HIP 44581 |
28.84 |
| 2026-04-06 12:00 |
09:04:20.32 |
+12:53:19.4 |
HIP 44581 |
28.82 |
| 2026-04-07 00:00 |
09:04:18.15 |
+12:53:30.6 |
HIP 44581 |
28.82 |
| 2026-04-07 12:00 |
09:04:16.01 |
+12:53:41.7 |
HIP 44581 |
28.83 |
| 2026-04-08 00:00 |
09:04:13.90 |
+12:53:52.6 |
HIP 44581 |
28.85 |
| 2026-04-08 12:00 |
09:04:11.83 |
+12:54:03.5 |
HIP 44581 |
28.87 |
| 2026-04-09 00:00 |
09:04:09.79 |
+12:54:14.2 |
HIP 44581 |
28.91 |
| 2026-04-09 12:00 |
09:04:07.78 |
+12:54:24.7 |
HIP 44581 |
28.95 |
| 2026-04-10 00:00 |
09:04:05.82 |
+12:54:35.1 |
HIP 44581 |
29.00 |
| 2026-04-10 12:00 |
09:04:03.88 |
+12:54:45.4 |
HIP 44581 |
29.06 |
| 2026-04-11 00:00 |
09:04:01.98 |
+12:54:55.5 |
HIP 44581 |
29.12 |
| 2026-04-11 12:00 |
09:04:00.12 |
+12:55:05.5 |
HIP 44581 |
29.19 |
| 2026-04-12 00:00 |
09:03:58.29 |
+12:55:15.3 |
HIP 44581 |
29.27 |
| 2026-04-12 12:00 |
09:03:56.50 |
+12:55:25.1 |
HIP 44581 |
29.35 |
| 2026-04-13 00:00 |
09:03:54.74 |
+12:55:34.6 |
HIP 44581 |
29.43 |
| 2026-04-13 12:00 |
09:03:53.02 |
+12:55:44.0 |
HIP 44581 |
29.52 |
| 2026-04-14 00:00 |
09:03:51.33 |
+12:55:53.3 |
HIP 44581 |
29.61 |
| 2026-04-14 12:00 |
09:03:49.68 |
+12:56:02.5 |
HIP 44581 |
29.71 |
| 2026-04-15 00:00 |
09:03:48.07 |
+12:56:11.4 |
HIP 44581 |
29.81 |
| 2026-04-15 12:00 |
09:03:46.49 |
+12:56:20.3 |
HIP 44581 |
29.91 |
| 2026-04-16 00:00 |
09:03:44.95 |
+12:56:29.0 |
HIP 44581 |
30.01 |