C/2008 T2 (Cardinal)
| 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
$$
M_a = (12.541 + 3.851\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.541 |
| n |
3.851 |
| 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 |
-32.2234 |
+17.473 |
| 2008-10-08 |
2009-04-10 |
+1.7554 |
-0.955 |
| 2009-04-10 |
2009-06-12 |
+23.0584 |
-5.440 |
| 2009-06-13 |
2009-10-10 |
+3.9852 |
-3.681 |
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 |
21:06:37.58 |
-04:11:22.3 |
HIP 104111 |
19.35 |
| 2026-02-03 12:00 |
21:06:40.79 |
-04:11:06.4 |
HIP 104111 |
20.17 |
| 2026-02-04 00:00 |
21:06:43.99 |
-04:10:50.3 |
HIP 104111 |
20.99 |
| 2026-02-04 12:00 |
21:06:47.19 |
-04:10:34.2 |
HIP 104111 |
21.81 |
| 2026-02-05 00:00 |
21:06:50.39 |
-04:10:18.0 |
HIP 104111 |
22.64 |
| 2026-02-05 12:00 |
21:06:53.59 |
-04:10:01.7 |
HIP 104111 |
23.46 |
| 2026-02-06 00:00 |
21:06:56.79 |
-04:09:45.4 |
HIP 104111 |
24.29 |
| 2026-02-06 12:00 |
21:06:59.98 |
-04:09:28.9 |
HIP 104111 |
25.12 |
| 2026-02-07 00:00 |
21:07:03.18 |
-04:09:12.3 |
HIP 104111 |
25.95 |
| 2026-02-07 12:00 |
21:07:06.37 |
-04:08:55.7 |
HIP 104111 |
26.78 |
| 2026-02-08 00:00 |
21:07:09.56 |
-04:08:39.0 |
HIP 104111 |
27.61 |
| 2026-02-08 12:00 |
21:07:12.75 |
-04:08:22.2 |
HIP 104111 |
28.45 |
| 2026-02-09 00:00 |
21:07:15.93 |
-04:08:05.3 |
HIP 104383 |
28.39 |
| 2026-02-09 12:00 |
21:07:19.11 |
-04:07:48.3 |
HIP 104383 |
27.95 |
| 2026-02-10 00:00 |
21:07:22.29 |
-04:07:31.3 |
HIP 104383 |
27.53 |
| 2026-02-10 12:00 |
21:07:25.47 |
-04:07:14.2 |
HIP 104383 |
27.13 |
| 2026-02-11 00:00 |
21:07:28.64 |
-04:06:57.0 |
HIP 104383 |
26.75 |
| 2026-02-11 12:00 |
21:07:31.81 |
-04:06:39.7 |
HIP 104383 |
26.40 |
| 2026-02-12 00:00 |
21:07:34.97 |
-04:06:22.4 |
HIP 104383 |
26.06 |
| 2026-02-12 12:00 |
21:07:38.13 |
-04:06:05.0 |
HIP 104383 |
25.76 |
| 2026-02-13 00:00 |
21:07:41.29 |
-04:05:47.5 |
HIP 104383 |
25.48 |
| 2026-02-13 12:00 |
21:07:44.44 |
-04:05:29.9 |
HIP 104383 |
25.23 |
| 2026-02-14 00:00 |
21:07:47.59 |
-04:05:12.3 |
HIP 104383 |
25.00 |
| 2026-02-14 12:00 |
21:07:50.73 |
-04:04:54.6 |
HIP 104383 |
24.80 |
| 2026-02-15 00:00 |
21:07:53.86 |
-04:04:36.8 |
HIP 104435 |
23.99 |
| 2026-02-15 12:00 |
21:07:56.99 |
-04:04:19.0 |
HIP 104435 |
23.16 |
| 2026-02-16 00:00 |
21:08:00.12 |
-04:04:01.1 |
HIP 104435 |
22.33 |
| 2026-02-16 12:00 |
21:08:03.24 |
-04:03:43.1 |
HIP 104435 |
21.50 |
| 2026-02-17 00:00 |
21:08:06.35 |
-04:03:25.1 |
HIP 104435 |
20.68 |
| 2026-02-17 12:00 |
21:08:09.45 |
-04:03:07.0 |
HIP 104435 |
19.85 |
| 2026-02-18 00:00 |
21:08:12.55 |
-04:02:48.8 |
HIP 104435 |
19.03 |
| 2026-02-18 12:00 |
21:08:15.64 |
-04:02:30.6 |
HIP 104435 |
18.21 |
| 2026-02-19 00:00 |
21:08:18.73 |
-04:02:12.4 |
HIP 104435 |
17.39 |
| 2026-02-19 12:00 |
21:08:21.81 |
-04:01:54.0 |
HIP 104435 |
16.57 |
| 2026-02-20 00:00 |
21:08:24.88 |
-04:01:35.6 |
HIP 104435 |
15.76 |
| 2026-02-20 12:00 |
21:08:27.94 |
-04:01:17.2 |
HIP 104435 |
14.94 |
| 2026-02-21 00:00 |
21:08:30.99 |
-04:00:58.7 |
HIP 104435 |
14.13 |
| 2026-02-21 12:00 |
21:08:34.04 |
-04:00:40.2 |
HIP 104435 |
13.33 |
| 2026-02-22 00:00 |
21:08:37.07 |
-04:00:21.6 |
HIP 104435 |
12.52 |
| 2026-02-22 12:00 |
21:08:40.10 |
-04:00:03.0 |
HIP 104435 |
11.72 |
| 2026-02-23 00:00 |
21:08:43.12 |
-03:59:44.3 |
HIP 104435 |
10.92 |
| 2026-02-23 12:00 |
21:08:46.13 |
-03:59:25.5 |
HIP 104435 |
10.13 |
| 2026-02-24 00:00 |
21:08:49.13 |
-03:59:06.8 |
HIP 104435 |
9.34 |