| 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) |
| 2026-03-26 00:00 |
04:07:05.42 |
+04:12:48.9 |
HIP 19266 |
11.85 |
| 2026-03-26 12:00 |
04:07:07.27 |
+04:13:16.8 |
HIP 19266 |
11.21 |
| 2026-03-27 00:00 |
04:07:09.14 |
+04:13:44.6 |
HIP 19266 |
10.57 |
| 2026-03-27 12:00 |
04:07:11.05 |
+04:14:12.4 |
HIP 19266 |
9.93 |
| 2026-03-28 00:00 |
04:07:13.00 |
+04:14:40.2 |
HIP 19266 |
9.28 |
| 2026-03-28 12:00 |
04:07:14.97 |
+04:15:08.0 |
HIP 19266 |
8.62 |
| 2026-03-29 00:00 |
04:07:16.98 |
+04:15:35.7 |
HIP 19266 |
7.96 |
| 2026-03-29 12:00 |
04:07:19.02 |
+04:16:03.4 |
HIP 19266 |
7.30 |
| 2026-03-30 00:00 |
04:07:21.09 |
+04:16:31.1 |
HIP 19266 |
6.64 |
| 2026-03-30 12:00 |
04:07:23.20 |
+04:16:58.7 |
HIP 19266 |
5.98 |
| 2026-03-31 00:00 |
04:07:25.33 |
+04:17:26.3 |
HIP 19266 |
5.32 |
| 2026-03-31 12:00 |
04:07:27.50 |
+04:17:53.9 |
HIP 19266 |
4.67 |
| 2026-04-01 00:00 |
04:07:29.70 |
+04:18:21.4 |
HIP 19266 |
4.03 |
| 2026-04-01 12:00 |
04:07:31.93 |
+04:18:48.9 |
HIP 19266 |
3.40 |
| 2026-04-02 00:00 |
04:07:34.19 |
+04:19:16.4 |
HIP 19266 |
2.82 |
| 2026-04-02 12:00 |
04:07:36.48 |
+04:19:43.8 |
HIP 19266 |
2.32 |
| 2026-04-03 00:00 |
04:07:38.80 |
+04:20:11.2 |
HIP 19266 |
1.95 |
| 2026-04-03 12:00 |
04:07:41.15 |
+04:20:38.5 |
HIP 19266 |
1.82 |
| 2026-04-04 00:00 |
04:07:43.53 |
+04:21:05.8 |
HIP 19266 |
1.98 |
| 2026-04-04 12:00 |
04:07:45.94 |
+04:21:33.1 |
HIP 19266 |
2.37 |
| 2026-04-05 00:00 |
04:07:48.38 |
+04:22:00.3 |
HIP 19266 |
2.91 |
| 2026-04-05 12:00 |
04:07:50.85 |
+04:22:27.4 |
HIP 19266 |
3.54 |
| 2026-04-06 00:00 |
04:07:53.35 |
+04:22:54.5 |
HIP 19266 |
4.21 |
| 2026-04-06 12:00 |
04:07:55.87 |
+04:23:21.5 |
HIP 19266 |
4.91 |
| 2026-04-07 00:00 |
04:07:58.43 |
+04:23:48.5 |
HIP 19266 |
5.64 |
| 2026-04-07 12:00 |
04:08:01.01 |
+04:24:15.5 |
HIP 19266 |
6.38 |
| 2026-04-08 00:00 |
04:08:03.62 |
+04:24:42.3 |
HIP 19266 |
7.13 |
| 2026-04-08 12:00 |
04:08:06.26 |
+04:25:09.2 |
HIP 19266 |
7.90 |
| 2026-04-09 00:00 |
04:08:08.92 |
+04:25:35.9 |
HIP 19280 |
8.66 |
| 2026-04-09 12:00 |
04:08:11.62 |
+04:26:02.6 |
HIP 19280 |
9.37 |
| 2026-04-10 00:00 |
04:08:14.34 |
+04:26:29.2 |
HIP 19280 |
10.09 |
| 2026-04-10 12:00 |
04:08:17.08 |
+04:26:55.8 |
HIP 19280 |
10.83 |
| 2026-04-11 00:00 |
04:08:19.86 |
+04:27:22.3 |
HIP 19280 |
11.58 |
| 2026-04-11 12:00 |
04:08:22.65 |
+04:27:48.7 |
HIP 19280 |
12.34 |
| 2026-04-12 00:00 |
04:08:25.48 |
+04:28:15.1 |
HIP 19280 |
13.11 |
| 2026-04-12 12:00 |
04:08:28.33 |
+04:28:41.4 |
HIP 19280 |
13.90 |
| 2026-04-13 00:00 |
04:08:31.21 |
+04:29:07.6 |
HIP 19280 |
14.69 |
| 2026-04-13 12:00 |
04:08:34.11 |
+04:29:33.8 |
HIP 19280 |
15.49 |
| 2026-04-14 00:00 |
04:08:37.03 |
+04:29:59.9 |
HIP 19280 |
16.30 |
| 2026-04-14 12:00 |
04:08:39.98 |
+04:30:25.9 |
HIP 19280 |
17.11 |
| 2026-04-15 00:00 |
04:08:42.96 |
+04:30:51.8 |
HIP 19280 |
17.93 |
| 2026-04-15 12:00 |
04:08:45.96 |
+04:31:17.6 |
HIP 19280 |
18.76 |
| 2026-04-16 00:00 |
04:08:48.98 |
+04:31:43.4 |
HIP 19280 |
19.60 |