| Parameter |
Value |
| Designation |
C/2008 T2 (Cardinal) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2009-06-13T05:44:59.979840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:24Z |
| Obs used |
1309 |
| NEO |
- |
| M1 |
11.200 |
| K1 |
5.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-02-08.0000000 |
| e |
1.00010902 |
| q (au) |
1.202208 |
| a (au) |
-11027.760878 |
| i (deg) |
56.303690 |
| Ω (om, deg) |
309.678521 |
| ω (w, deg) |
215.871148 |
| M (ma, deg) |
-0.000107 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.536 + 3.857\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.536 |
| n |
3.857 |
| gf |
1.000 |
| 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 |
| 2008-03-20 |
2008-10-08 |
-32.2881 |
+17.516 |
| 2008-10-08 |
2009-04-10 |
+1.8402 |
-0.993 |
| 2009-04-10 |
2009-06-12 |
+22.8692 |
-5.412 |
| 2009-06-13 |
2009-10-10 |
+3.9717 |
-3.676 |
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 |
21:07:52.39 |
-03:12:33.5 |
HIP 104373 |
30.74 |
| 2026-07-29 12:00 |
21:07:49.29 |
-03:12:43.8 |
HIP 104373 |
31.20 |
| 2026-07-30 00:00 |
21:07:46.18 |
-03:12:54.1 |
HIP 104373 |
31.68 |
| 2026-07-30 12:00 |
21:07:43.08 |
-03:13:04.6 |
HIP 104373 |
32.17 |
| 2026-07-31 00:00 |
21:07:39.97 |
-03:13:15.2 |
HIP 104373 |
32.68 |
| 2026-07-31 12:00 |
21:07:36.86 |
-03:13:26.0 |
HIP 104373 |
33.20 |
| 2026-08-01 00:00 |
21:07:33.74 |
-03:13:36.8 |
HIP 104373 |
33.73 |
| 2026-08-01 12:00 |
21:07:30.62 |
-03:13:47.7 |
HIP 104373 |
34.28 |
| 2026-08-02 00:00 |
21:07:27.50 |
-03:13:58.7 |
HIP 104373 |
34.84 |
| 2026-08-02 12:00 |
21:07:24.38 |
-03:14:09.9 |
HIP 104373 |
35.40 |
| 2026-08-03 00:00 |
21:07:21.25 |
-03:14:21.1 |
HIP 104373 |
35.98 |
| 2026-08-03 12:00 |
21:07:18.12 |
-03:14:32.5 |
HIP 104373 |
36.57 |
| 2026-08-04 00:00 |
21:07:14.99 |
-03:14:43.9 |
HIP 104373 |
37.17 |
| 2026-08-04 12:00 |
21:07:11.86 |
-03:14:55.5 |
HIP 104373 |
37.78 |
| 2026-08-05 00:00 |
21:07:08.73 |
-03:15:07.1 |
HIP 104373 |
38.39 |
| 2026-08-05 12:00 |
21:07:05.60 |
-03:15:18.9 |
HIP 104373 |
39.02 |
| 2026-08-06 00:00 |
21:07:02.47 |
-03:15:30.7 |
HIP 104373 |
39.65 |
| 2026-08-06 12:00 |
21:06:59.33 |
-03:15:42.7 |
HIP 104373 |
40.29 |
| 2026-08-07 00:00 |
21:06:56.20 |
-03:15:54.7 |
HIP 104373 |
40.94 |
| 2026-08-07 12:00 |
21:06:53.06 |
-03:16:06.9 |
HIP 104373 |
41.59 |
| 2026-08-08 00:00 |
21:06:49.93 |
-03:16:19.1 |
HIP 104373 |
42.25 |
| 2026-08-08 12:00 |
21:06:46.80 |
-03:16:31.4 |
HIP 104373 |
42.92 |
| 2026-08-09 00:00 |
21:06:43.67 |
-03:16:43.9 |
HIP 104373 |
43.59 |
| 2026-08-09 12:00 |
21:06:40.53 |
-03:16:56.4 |
HIP 104373 |
44.27 |
| 2026-08-10 00:00 |
21:06:37.40 |
-03:17:09.0 |
HIP 104373 |
44.96 |
| 2026-08-10 12:00 |
21:06:34.28 |
-03:17:21.7 |
HIP 104373 |
45.65 |
| 2026-08-11 00:00 |
21:06:31.15 |
-03:17:34.5 |
HIP 104373 |
46.34 |
| 2026-08-11 12:00 |
21:06:28.02 |
-03:17:47.4 |
HIP 104373 |
47.04 |
| 2026-08-12 00:00 |
21:06:24.90 |
-03:18:00.3 |
HIP 104373 |
47.74 |
| 2026-08-12 12:00 |
21:06:21.78 |
-03:18:13.4 |
HIP 104373 |
48.44 |
| 2026-08-13 00:00 |
21:06:18.67 |
-03:18:26.5 |
HIP 104373 |
49.15 |
| 2026-08-13 12:00 |
21:06:15.55 |
-03:18:39.7 |
HIP 104373 |
49.86 |
| 2026-08-14 00:00 |
21:06:12.44 |
-03:18:53.0 |
HIP 104373 |
50.58 |
| 2026-08-14 12:00 |
21:06:09.34 |
-03:19:06.4 |
HIP 104373 |
51.30 |
| 2026-08-15 00:00 |
21:06:06.23 |
-03:19:19.9 |
HIP 104373 |
52.02 |
| 2026-08-15 12:00 |
21:06:03.14 |
-03:19:33.4 |
HIP 104373 |
52.74 |
| 2026-08-16 00:00 |
21:06:00.04 |
-03:19:47.0 |
HIP 104373 |
53.47 |
| 2026-08-16 12:00 |
21:05:56.95 |
-03:20:00.7 |
HIP 104373 |
54.20 |
| 2026-08-17 00:00 |
21:05:53.87 |
-03:20:14.4 |
HIP 104373 |
54.93 |
| 2026-08-17 12:00 |
21:05:50.79 |
-03:20:28.3 |
HIP 104373 |
55.66 |
| 2026-08-18 00:00 |
21:05:47.72 |
-03:20:42.2 |
HIP 104373 |
56.40 |
| 2026-08-18 12:00 |
21:05:44.65 |
-03:20:56.2 |
HIP 104373 |
57.13 |
| 2026-08-19 00:00 |
21:05:41.59 |
-03:21:10.2 |
HIP 104373 |
57.87 |