| 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) |
| 2026-06-01 00:00 |
17:03:48.06 |
-15:10:25.2 |
HIP 83588 |
18.96 |
| 2026-06-01 12:00 |
17:03:42.16 |
-15:10:24.5 |
HIP 83588 |
20.32 |
| 2026-06-02 00:00 |
17:03:36.26 |
-15:10:23.9 |
HIP 83588 |
21.70 |
| 2026-06-02 12:00 |
17:03:30.35 |
-15:10:23.4 |
HIP 83588 |
23.08 |
| 2026-06-03 00:00 |
17:03:24.43 |
-15:10:23.0 |
HIP 83588 |
24.47 |
| 2026-06-03 12:00 |
17:03:18.52 |
-15:10:22.7 |
HIP 83588 |
25.86 |
| 2026-06-04 00:00 |
17:03:12.60 |
-15:10:22.4 |
HIP 83588 |
27.26 |
| 2026-06-04 12:00 |
17:03:06.68 |
-15:10:22.3 |
HIP 83588 |
28.66 |
| 2026-06-05 00:00 |
17:03:00.75 |
-15:10:22.2 |
HIP 83588 |
30.06 |
| 2026-06-05 12:00 |
17:02:54.83 |
-15:10:22.2 |
HIP 83588 |
31.46 |
| 2026-06-06 00:00 |
17:02:48.90 |
-15:10:22.3 |
HIP 83588 |
32.87 |
| 2026-06-06 12:00 |
17:02:42.97 |
-15:10:22.5 |
HIP 83588 |
34.28 |
| 2026-06-07 00:00 |
17:02:37.05 |
-15:10:22.7 |
HIP 83588 |
35.69 |
| 2026-06-07 12:00 |
17:02:31.12 |
-15:10:23.1 |
HIP 83463 |
36.42 |
| 2026-06-08 00:00 |
17:02:25.19 |
-15:10:23.6 |
HIP 83463 |
37.02 |
| 2026-06-08 12:00 |
17:02:19.27 |
-15:10:24.1 |
HIP 83463 |
37.65 |
| 2026-06-09 00:00 |
17:02:13.35 |
-15:10:24.8 |
HIP 83242 |
36.92 |
| 2026-06-09 12:00 |
17:02:07.42 |
-15:10:25.5 |
HIP 83242 |
36.11 |
| 2026-06-10 00:00 |
17:02:01.51 |
-15:10:26.3 |
HIP 83242 |
35.35 |
| 2026-06-10 12:00 |
17:01:55.59 |
-15:10:27.3 |
HIP 83242 |
34.63 |
| 2026-06-11 00:00 |
17:01:49.68 |
-15:10:28.3 |
HIP 83242 |
33.95 |
| 2026-06-11 12:00 |
17:01:43.78 |
-15:10:29.4 |
HIP 83242 |
33.31 |
| 2026-06-12 00:00 |
17:01:37.88 |
-15:10:30.6 |
HIP 83242 |
32.73 |
| 2026-06-12 12:00 |
17:01:31.98 |
-15:10:31.9 |
HIP 83242 |
32.20 |
| 2026-06-13 00:00 |
17:01:26.09 |
-15:10:33.3 |
HIP 83242 |
31.72 |
| 2026-06-13 12:00 |
17:01:20.21 |
-15:10:34.8 |
HIP 83242 |
31.29 |
| 2026-06-14 00:00 |
17:01:14.33 |
-15:10:36.4 |
HIP 83242 |
30.93 |
| 2026-06-14 12:00 |
17:01:08.47 |
-15:10:38.1 |
HIP 83242 |
30.62 |
| 2026-06-15 00:00 |
17:01:02.61 |
-15:10:39.9 |
HIP 83242 |
30.38 |
| 2026-06-15 12:00 |
17:00:56.76 |
-15:10:41.8 |
HIP 83242 |
30.19 |
| 2026-06-16 00:00 |
17:00:50.91 |
-15:10:43.8 |
HIP 83242 |
30.07 |
| 2026-06-16 12:00 |
17:00:45.08 |
-15:10:45.9 |
HIP 83242 |
30.02 |
| 2026-06-17 00:00 |
17:00:39.26 |
-15:10:48.1 |
HIP 83242 |
30.03 |
| 2026-06-17 12:00 |
17:00:33.45 |
-15:10:50.5 |
HIP 83242 |
30.10 |
| 2026-06-18 00:00 |
17:00:27.65 |
-15:10:52.9 |
HIP 83242 |
30.24 |
| 2026-06-18 12:00 |
17:00:21.86 |
-15:10:55.4 |
HIP 83242 |
30.43 |
| 2026-06-19 00:00 |
17:00:16.09 |
-15:10:58.0 |
HIP 83090 |
29.56 |
| 2026-06-19 12:00 |
17:00:10.33 |
-15:11:00.7 |
HIP 83090 |
28.53 |
| 2026-06-20 00:00 |
17:00:04.58 |
-15:11:03.6 |
HIP 83090 |
27.54 |
| 2026-06-20 12:00 |
16:59:58.84 |
-15:11:06.5 |
HIP 83090 |
26.58 |
| 2026-06-21 00:00 |
16:59:53.12 |
-15:11:09.5 |
HIP 83090 |
25.67 |
| 2026-06-21 12:00 |
16:59:47.42 |
-15:11:12.7 |
HIP 83090 |
24.80 |
| 2026-06-22 00:00 |
16:59:41.73 |
-15:11:15.9 |
HIP 83090 |
23.99 |