| 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) |
| 2026-07-29 00:00 |
16:53:52.31 |
-15:20:23.9 |
HIP 82877 |
34.67 |
| 2026-07-29 12:00 |
16:53:48.91 |
-15:20:35.5 |
HIP 82877 |
35.49 |
| 2026-07-30 00:00 |
16:53:45.55 |
-15:20:47.2 |
HIP 82877 |
36.29 |
| 2026-07-30 12:00 |
16:53:42.23 |
-15:20:59.1 |
HIP 82877 |
37.09 |
| 2026-07-31 00:00 |
16:53:38.96 |
-15:21:11.0 |
HIP 82536 |
37.67 |
| 2026-07-31 12:00 |
16:53:35.73 |
-15:21:23.1 |
HIP 82536 |
37.09 |
| 2026-08-01 00:00 |
16:53:32.55 |
-15:21:35.3 |
HIP 82536 |
36.52 |
| 2026-08-01 12:00 |
16:53:29.41 |
-15:21:47.5 |
HIP 82536 |
35.96 |
| 2026-08-02 00:00 |
16:53:26.31 |
-15:22:00.0 |
HIP 82536 |
35.41 |
| 2026-08-02 12:00 |
16:53:23.25 |
-15:22:12.4 |
HIP 82536 |
34.88 |
| 2026-08-03 00:00 |
16:53:20.24 |
-15:22:25.0 |
HIP 82536 |
34.36 |
| 2026-08-03 12:00 |
16:53:17.28 |
-15:22:37.7 |
HIP 82536 |
33.85 |
| 2026-08-04 00:00 |
16:53:14.36 |
-15:22:50.5 |
HIP 82536 |
33.35 |
| 2026-08-04 12:00 |
16:53:11.49 |
-15:23:03.4 |
HIP 82536 |
32.86 |
| 2026-08-05 00:00 |
16:53:08.66 |
-15:23:16.5 |
HIP 82536 |
32.39 |
| 2026-08-05 12:00 |
16:53:05.87 |
-15:23:29.6 |
HIP 82536 |
31.92 |
| 2026-08-06 00:00 |
16:53:03.13 |
-15:23:42.8 |
HIP 82536 |
31.47 |
| 2026-08-06 12:00 |
16:53:00.44 |
-15:23:56.2 |
HIP 82536 |
31.03 |
| 2026-08-07 00:00 |
16:52:57.79 |
-15:24:09.6 |
HIP 82536 |
30.60 |
| 2026-08-07 12:00 |
16:52:55.19 |
-15:24:23.2 |
HIP 82536 |
30.18 |
| 2026-08-08 00:00 |
16:52:52.64 |
-15:24:36.8 |
HIP 82536 |
29.77 |
| 2026-08-08 12:00 |
16:52:50.13 |
-15:24:50.6 |
HIP 82536 |
29.38 |
| 2026-08-09 00:00 |
16:52:47.67 |
-15:25:04.4 |
HIP 82536 |
28.99 |
| 2026-08-09 12:00 |
16:52:45.26 |
-15:25:18.4 |
HIP 82536 |
28.61 |
| 2026-08-10 00:00 |
16:52:42.89 |
-15:25:32.5 |
HIP 82536 |
28.24 |
| 2026-08-10 12:00 |
16:52:40.57 |
-15:25:46.7 |
HIP 82536 |
27.89 |
| 2026-08-11 00:00 |
16:52:38.30 |
-15:26:00.9 |
HIP 82536 |
27.54 |
| 2026-08-11 12:00 |
16:52:36.08 |
-15:26:15.3 |
HIP 82536 |
27.20 |
| 2026-08-12 00:00 |
16:52:33.90 |
-15:26:29.8 |
HIP 82536 |
26.87 |
| 2026-08-12 12:00 |
16:52:31.77 |
-15:26:44.4 |
HIP 82536 |
26.55 |
| 2026-08-13 00:00 |
16:52:29.69 |
-15:26:59.0 |
HIP 82536 |
26.23 |
| 2026-08-13 12:00 |
16:52:27.66 |
-15:27:13.8 |
HIP 82536 |
25.93 |
| 2026-08-14 00:00 |
16:52:25.68 |
-15:27:28.7 |
HIP 82536 |
25.63 |
| 2026-08-14 12:00 |
16:52:23.75 |
-15:27:43.7 |
HIP 82536 |
25.34 |
| 2026-08-15 00:00 |
16:52:21.86 |
-15:27:58.7 |
HIP 82536 |
25.06 |
| 2026-08-15 12:00 |
16:52:20.03 |
-15:28:13.9 |
HIP 82536 |
24.78 |
| 2026-08-16 00:00 |
16:52:18.24 |
-15:28:29.2 |
HIP 82536 |
24.51 |
| 2026-08-16 12:00 |
16:52:16.50 |
-15:28:44.5 |
HIP 82536 |
24.24 |
| 2026-08-17 00:00 |
16:52:14.81 |
-15:29:00.0 |
HIP 82536 |
23.98 |
| 2026-08-17 12:00 |
16:52:13.17 |
-15:29:15.5 |
HIP 82536 |
23.73 |
| 2026-08-18 00:00 |
16:52:11.58 |
-15:29:31.2 |
HIP 82536 |
23.48 |
| 2026-08-18 12:00 |
16:52:10.04 |
-15:29:46.9 |
HIP 82536 |
23.23 |
| 2026-08-19 00:00 |
16:52:08.55 |
-15:30:02.7 |
HIP 82536 |
22.99 |