| Parameter |
Value |
| Designation |
C/2016 R2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-05-09T13:59:38.526720Z |
| Orbit solution date (soln_date, UTC) |
2021-07-01T22:12:39Z |
| Obs used |
4319 |
| NEO |
- |
| M1 |
7.300 |
| K1 |
9.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-05-29.0000000 |
| e |
0.99630739 |
| q (au) |
2.602364 |
| a (au) |
704.748706 |
| i (deg) |
58.224063 |
| Ω (om, deg) |
80.569029 |
| ω (w, deg) |
33.191899 |
| M (ma, deg) |
0.001023 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.079 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.079 |
| n |
2.000 |
| gf |
0.973 |
| gb |
-0.500 |
| k |
0.801 |
| δ90 |
1.411 |
| 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 |
| 2016-08-30 |
2017-12-27 |
-1.8441 |
+0.387 |
| 2017-12-27 |
2018-05-08 |
+20.4771 |
-9.983 |
| 2018-05-09 |
2021-06-27 |
+6.0713 |
-4.191 |
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 |
16:52:16.16 |
-15:49:35.5 |
HIP 82536 |
3.40 |
| 2026-09-20 12:00 |
16:52:17.87 |
-15:49:55.7 |
HIP 82536 |
3.12 |
| 2026-09-21 00:00 |
16:52:19.62 |
-15:50:16.0 |
HIP 82536 |
2.92 |
| 2026-09-21 12:00 |
16:52:21.42 |
-15:50:36.4 |
HIP 82536 |
2.82 |
| 2026-09-22 00:00 |
16:52:23.26 |
-15:50:56.8 |
HIP 82536 |
2.83 |
| 2026-09-22 12:00 |
16:52:25.15 |
-15:51:17.2 |
HIP 82536 |
2.96 |
| 2026-09-23 00:00 |
16:52:27.09 |
-15:51:37.6 |
HIP 82536 |
3.19 |
| 2026-09-23 12:00 |
16:52:29.07 |
-15:51:58.1 |
HIP 82536 |
3.51 |
| 2026-09-24 00:00 |
16:52:31.10 |
-15:52:18.7 |
HIP 82536 |
3.91 |
| 2026-09-24 12:00 |
16:52:33.18 |
-15:52:39.2 |
HIP 82536 |
4.36 |
| 2026-09-25 00:00 |
16:52:35.30 |
-15:52:59.8 |
HIP 82536 |
4.86 |
| 2026-09-25 12:00 |
16:52:37.46 |
-15:53:20.4 |
HIP 82536 |
5.39 |
| 2026-09-26 00:00 |
16:52:39.67 |
-15:53:41.1 |
HIP 82536 |
5.95 |
| 2026-09-26 12:00 |
16:52:41.92 |
-15:54:01.8 |
HIP 82536 |
6.54 |
| 2026-09-27 00:00 |
16:52:44.22 |
-15:54:22.5 |
HIP 82536 |
7.14 |
| 2026-09-27 12:00 |
16:52:46.56 |
-15:54:43.2 |
HIP 82536 |
7.77 |
| 2026-09-28 00:00 |
16:52:48.95 |
-15:55:04.0 |
HIP 82536 |
8.41 |
| 2026-09-28 12:00 |
16:52:51.38 |
-15:55:24.8 |
HIP 82536 |
9.06 |
| 2026-09-29 00:00 |
16:52:53.86 |
-15:55:45.6 |
HIP 82536 |
9.73 |
| 2026-09-29 12:00 |
16:52:56.37 |
-15:56:06.5 |
HIP 82536 |
10.41 |
| 2026-09-30 00:00 |
16:52:58.94 |
-15:56:27.3 |
HIP 82536 |
11.10 |
| 2026-09-30 12:00 |
16:53:01.54 |
-15:56:48.2 |
HIP 82536 |
11.81 |
| 2026-10-01 00:00 |
16:53:04.19 |
-15:57:09.2 |
HIP 82536 |
12.52 |
| 2026-10-01 12:00 |
16:53:06.88 |
-15:57:30.1 |
HIP 82536 |
13.25 |
| 2026-10-02 00:00 |
16:53:09.62 |
-15:57:51.1 |
HIP 82536 |
13.99 |
| 2026-10-02 12:00 |
16:53:12.39 |
-15:58:12.1 |
HIP 82581 |
14.29 |
| 2026-10-03 00:00 |
16:53:15.21 |
-15:58:33.1 |
HIP 82581 |
14.17 |
| 2026-10-03 12:00 |
16:53:18.08 |
-15:58:54.1 |
HIP 82581 |
14.09 |
| 2026-10-04 00:00 |
16:53:20.98 |
-15:59:15.1 |
HIP 82581 |
14.06 |
| 2026-10-04 12:00 |
16:53:23.93 |
-15:59:36.2 |
HIP 82581 |
14.07 |
| 2026-10-05 00:00 |
16:53:26.92 |
-15:59:57.2 |
HIP 82581 |
14.14 |
| 2026-10-05 12:00 |
16:53:29.95 |
-16:00:18.3 |
HIP 82581 |
14.25 |
| 2026-10-06 00:00 |
16:53:33.02 |
-16:00:39.4 |
HIP 82581 |
14.42 |
| 2026-10-06 12:00 |
16:53:36.13 |
-16:01:00.5 |
HIP 82581 |
14.64 |
| 2026-10-07 00:00 |
16:53:39.29 |
-16:01:21.6 |
HIP 82581 |
14.90 |
| 2026-10-07 12:00 |
16:53:42.48 |
-16:01:42.8 |
HIP 82581 |
15.22 |
| 2026-10-08 00:00 |
16:53:45.72 |
-16:02:03.9 |
HIP 82581 |
15.58 |
| 2026-10-08 12:00 |
16:53:48.99 |
-16:02:25.1 |
HIP 82581 |
15.98 |
| 2026-10-09 00:00 |
16:53:52.31 |
-16:02:46.2 |
HIP 82581 |
16.43 |
| 2026-10-09 12:00 |
16:53:55.66 |
-16:03:07.4 |
HIP 82581 |
16.92 |
| 2026-10-10 00:00 |
16:53:59.06 |
-16:03:28.5 |
HIP 82581 |
17.45 |
| 2026-10-10 12:00 |
16:54:02.49 |
-16:03:49.7 |
HIP 82581 |
18.02 |
| 2026-10-11 00:00 |
16:54:05.97 |
-16:04:10.9 |
HIP 82581 |
18.62 |