C/2013 G9 (Tenagra)
| Parameter |
Value |
| Designation |
C/2013 G9 (Tenagra) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-01-14T14:39:54.149760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:34Z |
| Obs used |
496 |
| NEO |
- |
| M1 |
6.500 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2014-06-28.0000000 |
| e |
1.00127209 |
| q (au) |
5.337621 |
| a (au) |
-4195.948868 |
| i (deg) |
146.233595 |
| Ω (om, deg) |
35.688660 |
| ω (w, deg) |
204.930440 |
| M (ma, deg) |
-0.000727 |
Magnitude
Scatter + Global Linear
$$
M_a = (1.736 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
1.736 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.953 |
| k |
1.000 |
| 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 |
| 2013-04-09 |
2015-01-12 |
+0.8615 |
-0.712 |
| 2015-01-17 |
2016-04-06 |
+15.2777 |
-11.324 |
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 |
04:07:24.97 |
+03:29:10.4 |
HIP 19170 |
21.46 |
| 2026-02-03 12:00 |
04:07:22.61 |
+03:29:30.9 |
HIP 19170 |
20.85 |
| 2026-02-04 00:00 |
04:07:20.30 |
+03:29:51.4 |
HIP 19170 |
20.24 |
| 2026-02-04 12:00 |
04:07:18.04 |
+03:30:12.2 |
HIP 19170 |
19.65 |
| 2026-02-05 00:00 |
04:07:15.81 |
+03:30:33.1 |
HIP 19170 |
19.06 |
| 2026-02-05 12:00 |
04:07:13.63 |
+03:30:54.1 |
HIP 19170 |
18.48 |
| 2026-02-06 00:00 |
04:07:11.49 |
+03:31:15.3 |
HIP 19170 |
17.91 |
| 2026-02-06 12:00 |
04:07:09.40 |
+03:31:36.7 |
HIP 19170 |
17.35 |
| 2026-02-07 00:00 |
04:07:07.35 |
+03:31:58.2 |
HIP 19170 |
16.79 |
| 2026-02-07 12:00 |
04:07:05.34 |
+03:32:19.9 |
HIP 19170 |
16.24 |
| 2026-02-08 00:00 |
04:07:03.38 |
+03:32:41.7 |
HIP 19170 |
15.70 |
| 2026-02-08 12:00 |
04:07:01.46 |
+03:33:03.7 |
HIP 19170 |
15.16 |
| 2026-02-09 00:00 |
04:06:59.58 |
+03:33:25.8 |
HIP 19170 |
14.64 |
| 2026-02-09 12:00 |
04:06:57.75 |
+03:33:48.0 |
HIP 19170 |
14.12 |
| 2026-02-10 00:00 |
04:06:55.97 |
+03:34:10.4 |
HIP 19170 |
13.60 |
| 2026-02-10 12:00 |
04:06:54.22 |
+03:34:33.0 |
HIP 19170 |
13.10 |
| 2026-02-11 00:00 |
04:06:52.52 |
+03:34:55.7 |
HIP 19170 |
12.60 |
| 2026-02-11 12:00 |
04:06:50.87 |
+03:35:18.5 |
HIP 19170 |
12.11 |
| 2026-02-12 00:00 |
04:06:49.26 |
+03:35:41.4 |
HIP 19170 |
11.63 |
| 2026-02-12 12:00 |
04:06:47.69 |
+03:36:04.5 |
HIP 19170 |
11.15 |
| 2026-02-13 00:00 |
04:06:46.17 |
+03:36:27.8 |
HIP 19170 |
10.69 |
| 2026-02-13 12:00 |
04:06:44.69 |
+03:36:51.1 |
HIP 19170 |
10.23 |
| 2026-02-14 00:00 |
04:06:43.26 |
+03:37:14.6 |
HIP 19170 |
9.77 |
| 2026-02-14 12:00 |
04:06:41.87 |
+03:37:38.2 |
HIP 19170 |
9.33 |
| 2026-02-15 00:00 |
04:06:40.52 |
+03:38:02.0 |
HIP 19170 |
8.89 |
| 2026-02-15 12:00 |
04:06:39.22 |
+03:38:25.8 |
HIP 19170 |
8.46 |
| 2026-02-16 00:00 |
04:06:37.96 |
+03:38:49.8 |
HIP 19170 |
8.04 |
| 2026-02-16 12:00 |
04:06:36.75 |
+03:39:13.9 |
HIP 19170 |
7.63 |
| 2026-02-17 00:00 |
04:06:35.58 |
+03:39:38.1 |
HIP 19170 |
7.23 |
| 2026-02-17 12:00 |
04:06:34.46 |
+03:40:02.5 |
HIP 19170 |
6.83 |
| 2026-02-18 00:00 |
04:06:33.38 |
+03:40:27.0 |
HIP 19170 |
6.45 |
| 2026-02-18 12:00 |
04:06:32.34 |
+03:40:51.5 |
HIP 19170 |
6.08 |
| 2026-02-19 00:00 |
04:06:31.35 |
+03:41:16.2 |
HIP 19170 |
5.72 |
| 2026-02-19 12:00 |
04:06:30.40 |
+03:41:41.0 |
HIP 19170 |
5.38 |
| 2026-02-20 00:00 |
04:06:29.50 |
+03:42:05.9 |
HIP 19170 |
5.05 |
| 2026-02-20 12:00 |
04:06:28.64 |
+03:42:30.9 |
HIP 19170 |
4.74 |
| 2026-02-21 00:00 |
04:06:27.82 |
+03:42:56.0 |
HIP 19170 |
4.45 |
| 2026-02-21 12:00 |
04:06:27.05 |
+03:43:21.2 |
HIP 19170 |
4.19 |
| 2026-02-22 00:00 |
04:06:26.32 |
+03:43:46.5 |
HIP 19170 |
3.96 |
| 2026-02-22 12:00 |
04:06:25.64 |
+03:44:11.9 |
HIP 19170 |
3.75 |
| 2026-02-23 00:00 |
04:06:25.00 |
+03:44:37.4 |
HIP 19170 |
3.59 |
| 2026-02-23 12:00 |
04:06:24.40 |
+03:45:03.0 |
HIP 19170 |
3.47 |
| 2026-02-24 00:00 |
04:06:23.85 |
+03:45:28.7 |
HIP 19170 |
3.39 |