| 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) |
| 2026-05-12 00:00 |
04:11:51.66 |
+04:51:37.2 |
HIP 19636 |
9.51 |
| 2026-05-12 12:00 |
04:11:55.52 |
+04:51:56.9 |
HIP 19636 |
8.68 |
| 2026-05-13 00:00 |
04:11:59.40 |
+04:52:16.3 |
HIP 19636 |
7.89 |
| 2026-05-13 12:00 |
04:12:03.28 |
+04:52:35.7 |
HIP 19636 |
7.16 |
| 2026-05-14 00:00 |
04:12:07.17 |
+04:52:54.9 |
HIP 19636 |
6.50 |
| 2026-05-14 12:00 |
04:12:11.07 |
+04:53:13.9 |
HIP 19636 |
5.95 |
| 2026-05-15 00:00 |
04:12:14.98 |
+04:53:32.8 |
HIP 19636 |
5.52 |
| 2026-05-15 12:00 |
04:12:18.89 |
+04:53:51.5 |
HIP 19636 |
5.26 |
| 2026-05-16 00:00 |
04:12:22.81 |
+04:54:10.1 |
HIP 19636 |
5.18 |
| 2026-05-16 12:00 |
04:12:26.73 |
+04:54:28.6 |
HIP 19636 |
5.31 |
| 2026-05-17 00:00 |
04:12:30.66 |
+04:54:46.8 |
HIP 19636 |
5.62 |
| 2026-05-17 12:00 |
04:12:34.60 |
+04:55:05.0 |
HIP 19636 |
6.08 |
| 2026-05-18 00:00 |
04:12:38.54 |
+04:55:22.9 |
HIP 19657 |
6.59 |
| 2026-05-18 12:00 |
04:12:42.48 |
+04:55:40.7 |
HIP 19657 |
6.18 |
| 2026-05-19 00:00 |
04:12:46.43 |
+04:55:58.4 |
HIP 19657 |
5.93 |
| 2026-05-19 12:00 |
04:12:50.39 |
+04:56:15.9 |
HIP 19657 |
5.85 |
| 2026-05-20 00:00 |
04:12:54.35 |
+04:56:33.2 |
HIP 19657 |
5.95 |
| 2026-05-20 12:00 |
04:12:58.31 |
+04:56:50.4 |
HIP 19657 |
6.23 |
| 2026-05-21 00:00 |
04:13:02.27 |
+04:57:07.4 |
HIP 19657 |
6.66 |
| 2026-05-21 12:00 |
04:13:06.24 |
+04:57:24.3 |
HIP 19657 |
7.21 |
| 2026-05-22 00:00 |
04:13:10.21 |
+04:57:41.0 |
HIP 19657 |
7.86 |
| 2026-05-22 12:00 |
04:13:14.18 |
+04:57:57.5 |
HIP 19657 |
8.59 |
| 2026-05-23 00:00 |
04:13:18.15 |
+04:58:13.9 |
HIP 19657 |
9.37 |
| 2026-05-23 12:00 |
04:13:22.13 |
+04:58:30.1 |
HIP 19657 |
10.20 |
| 2026-05-24 00:00 |
04:13:26.11 |
+04:58:46.2 |
HIP 19657 |
11.06 |
| 2026-05-24 12:00 |
04:13:30.08 |
+04:59:02.0 |
HIP 19657 |
11.95 |
| 2026-05-25 00:00 |
04:13:34.06 |
+04:59:17.8 |
HIP 19657 |
12.86 |
| 2026-05-25 12:00 |
04:13:38.04 |
+04:59:33.3 |
HIP 19657 |
13.79 |
| 2026-05-26 00:00 |
04:13:42.02 |
+04:59:48.7 |
HIP 19657 |
14.73 |
| 2026-05-26 12:00 |
04:13:46.00 |
+05:00:03.9 |
HIP 19657 |
15.68 |
| 2026-05-27 00:00 |
04:13:49.98 |
+05:00:19.0 |
HIP 19657 |
16.64 |
| 2026-05-27 12:00 |
04:13:53.95 |
+05:00:33.8 |
HIP 19657 |
17.60 |
| 2026-05-28 00:00 |
04:13:57.93 |
+05:00:48.5 |
HIP 19818 |
18.18 |
| 2026-05-28 12:00 |
04:14:01.91 |
+05:01:03.1 |
HIP 19818 |
17.22 |
| 2026-05-29 00:00 |
04:14:05.88 |
+05:01:17.5 |
HIP 19818 |
16.27 |
| 2026-05-29 12:00 |
04:14:09.85 |
+05:01:31.7 |
HIP 19818 |
15.33 |
| 2026-05-30 00:00 |
04:14:13.82 |
+05:01:45.7 |
HIP 19818 |
14.40 |
| 2026-05-30 12:00 |
04:14:17.79 |
+05:01:59.6 |
HIP 19818 |
13.49 |
| 2026-05-31 00:00 |
04:14:21.76 |
+05:02:13.3 |
HIP 19818 |
12.60 |
| 2026-05-31 12:00 |
04:14:25.72 |
+05:02:26.8 |
HIP 19818 |
11.72 |
| 2026-06-01 00:00 |
04:14:29.68 |
+05:02:40.1 |
HIP 19818 |
10.88 |
| 2026-06-01 12:00 |
04:14:33.63 |
+05:02:53.3 |
HIP 19818 |
10.07 |
| 2026-06-02 00:00 |
04:14:37.59 |
+05:03:06.3 |
HIP 19818 |
9.29 |