| 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) |
| 2026-09-20 00:00 |
04:20:08.26 |
+04:40:06.2 |
HIP 20203 |
8.50 |
| 2026-09-20 12:00 |
04:20:05.89 |
+04:39:45.5 |
HIP 20203 |
8.42 |
| 2026-09-21 00:00 |
04:20:03.48 |
+04:39:24.9 |
HIP 20203 |
8.40 |
| 2026-09-21 12:00 |
04:20:01.03 |
+04:39:04.2 |
HIP 20203 |
8.43 |
| 2026-09-22 00:00 |
04:19:58.54 |
+04:38:43.4 |
HIP 20203 |
8.52 |
| 2026-09-22 12:00 |
04:19:56.02 |
+04:38:22.7 |
HIP 20203 |
8.66 |
| 2026-09-23 00:00 |
04:19:53.45 |
+04:38:01.9 |
HIP 20203 |
8.86 |
| 2026-09-23 12:00 |
04:19:50.84 |
+04:37:41.0 |
HIP 20203 |
9.10 |
| 2026-09-24 00:00 |
04:19:48.20 |
+04:37:20.2 |
HIP 20203 |
9.41 |
| 2026-09-24 12:00 |
04:19:45.52 |
+04:36:59.3 |
HIP 20203 |
9.76 |
| 2026-09-25 00:00 |
04:19:42.80 |
+04:36:38.3 |
HIP 20203 |
10.15 |
| 2026-09-25 12:00 |
04:19:40.04 |
+04:36:17.4 |
HIP 20203 |
10.59 |
| 2026-09-26 00:00 |
04:19:37.24 |
+04:35:56.4 |
HIP 20203 |
11.06 |
| 2026-09-26 12:00 |
04:19:34.41 |
+04:35:35.4 |
HIP 20203 |
11.58 |
| 2026-09-27 00:00 |
04:19:31.53 |
+04:35:14.4 |
HIP 20203 |
12.12 |
| 2026-09-27 12:00 |
04:19:28.62 |
+04:34:53.4 |
HIP 20203 |
12.70 |
| 2026-09-28 00:00 |
04:19:25.67 |
+04:34:32.4 |
HIP 20203 |
13.30 |
| 2026-09-28 12:00 |
04:19:22.69 |
+04:34:11.3 |
HIP 20203 |
13.93 |
| 2026-09-29 00:00 |
04:19:19.66 |
+04:33:50.2 |
HIP 20203 |
14.58 |
| 2026-09-29 12:00 |
04:19:16.60 |
+04:33:29.2 |
HIP 20111 |
14.45 |
| 2026-09-30 00:00 |
04:19:13.50 |
+04:33:08.1 |
HIP 20111 |
14.29 |
| 2026-09-30 12:00 |
04:19:10.37 |
+04:32:47.0 |
HIP 20111 |
14.18 |
| 2026-10-01 00:00 |
04:19:07.20 |
+04:32:25.9 |
HIP 20111 |
14.11 |
| 2026-10-01 12:00 |
04:19:03.99 |
+04:32:04.8 |
HIP 20111 |
14.09 |
| 2026-10-02 00:00 |
04:19:00.74 |
+04:31:43.6 |
HIP 20111 |
14.13 |
| 2026-10-02 12:00 |
04:18:57.46 |
+04:31:22.5 |
HIP 20111 |
14.21 |
| 2026-10-03 00:00 |
04:18:54.15 |
+04:31:01.4 |
HIP 20111 |
14.35 |
| 2026-10-03 12:00 |
04:18:50.79 |
+04:30:40.3 |
HIP 20111 |
14.55 |
| 2026-10-04 00:00 |
04:18:47.40 |
+04:30:19.2 |
HIP 20111 |
14.79 |
| 2026-10-04 12:00 |
04:18:43.98 |
+04:29:58.1 |
HIP 20111 |
15.09 |
| 2026-10-05 00:00 |
04:18:40.51 |
+04:29:37.0 |
HIP 20111 |
15.43 |
| 2026-10-05 12:00 |
04:18:37.02 |
+04:29:16.0 |
HIP 20111 |
15.82 |
| 2026-10-06 00:00 |
04:18:33.49 |
+04:28:54.9 |
HIP 20111 |
16.26 |
| 2026-10-06 12:00 |
04:18:29.92 |
+04:28:33.8 |
HIP 20111 |
16.74 |
| 2026-10-07 00:00 |
04:18:26.32 |
+04:28:12.8 |
HIP 20111 |
17.27 |
| 2026-10-07 12:00 |
04:18:22.68 |
+04:27:51.8 |
HIP 20111 |
17.83 |
| 2026-10-08 00:00 |
04:18:19.01 |
+04:27:30.8 |
HIP 20111 |
18.43 |
| 2026-10-08 12:00 |
04:18:15.30 |
+04:27:09.8 |
HIP 20111 |
19.06 |
| 2026-10-09 00:00 |
04:18:11.56 |
+04:26:48.9 |
HIP 20111 |
19.73 |
| 2026-10-09 12:00 |
04:18:07.79 |
+04:26:28.0 |
HIP 19971 |
19.16 |
| 2026-10-10 00:00 |
04:18:03.98 |
+04:26:07.1 |
HIP 19971 |
18.38 |
| 2026-10-10 12:00 |
04:18:00.14 |
+04:25:46.2 |
HIP 19971 |
17.62 |
| 2026-10-11 00:00 |
04:17:56.27 |
+04:25:25.4 |
HIP 19971 |
16.88 |