P/2021 R5 (Rankin)

Metadata

Parameter Value
Designation P/2021 R5 (Rankin)
Type P
Perihelion (tp_cal, UTC) 2022-01-11T23:34:59.966400Z
Orbit solution date (soln_date, UTC) 2024-04-29T13:12:24Z
Obs used 251
NEO -
M1 7.200
K1 18.750
PC 0.030
Discovery observation (MPC, UTC) 2021-09-09T06:52:28.416000Z
Discovery magnitude (MPC) 19.34 G
Discovery observatory (MPC) G96 · University of Arizona Mt. Lemmon Survey
Osculating Elements
Parameter Value
Epoch (epoch_cal, TDB) 2021-10-17.0000000
e 0.30753521
q (au) 3.322719
a (au) 4.798394
i (deg) 7.852203
Ω (om, deg) 219.963779
ω (w, deg) 167.335702
M (ma, deg) 351.843709

Magnitude

P/2021 R5 (Rankin) · Magnitude (Full range)

Scatter + Global Linear

$$ M_a = (8.399 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter Value
H0 8.399
n 6.000
gf 0.975
gb -0.934
k 1.000
δ90 9.557
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

Ephemeris

Date/Time (UTC) RA (J2000) Dec (J2000) Nearest HIP Dist from HIP (arcmin)
2026-06-01 00:00 12:01:02.54 -04:37:23.0 HIP 58558 9.81
2026-06-01 12:00 12:01:02.77 -04:36:49.6 HIP 58558 9.62
2026-06-02 00:00 12:01:03.15 -04:36:17.3 HIP 58558 9.50
2026-06-02 12:00 12:01:03.68 -04:35:45.9 HIP 58558 9.45
2026-06-03 00:00 12:01:04.35 -04:35:15.5 HIP 58558 9.48
2026-06-03 12:00 12:01:05.17 -04:34:46.0 HIP 58558 9.57
2026-06-04 00:00 12:01:06.14 -04:34:17.6 HIP 58558 9.72
2026-06-04 12:00 12:01:07.26 -04:33:50.2 HIP 58558 9.95
2026-06-05 00:00 12:01:08.52 -04:33:23.7 HIP 58558 10.23
2026-06-05 12:00 12:01:09.93 -04:32:58.2 HIP 58558 10.57
2026-06-06 00:00 12:01:11.49 -04:32:33.7 HIP 58558 10.96
2026-06-06 12:00 12:01:13.19 -04:32:10.2 HIP 58558 11.41
2026-06-07 00:00 12:01:15.04 -04:31:47.7 HIP 58558 11.89
2026-06-07 12:00 12:01:17.03 -04:31:26.1 HIP 58558 12.43
2026-06-08 00:00 12:01:19.17 -04:31:05.6 HIP 58558 13.00
2026-06-08 12:00 12:01:21.45 -04:30:46.0 HIP 58558 13.61
2026-06-09 00:00 12:01:23.88 -04:30:27.4 HIP 58558 14.26
2026-06-09 12:00 12:01:26.45 -04:30:09.8 HIP 58558 14.94
2026-06-10 00:00 12:01:29.17 -04:29:53.2 HIP 58558 15.66
2026-06-10 12:00 12:01:32.03 -04:29:37.6 HIP 58558 16.41
2026-06-11 00:00 12:01:35.03 -04:29:22.9 HIP 58558 17.19
2026-06-11 12:00 12:01:38.18 -04:29:09.3 HIP 58558 18.01
2026-06-12 00:00 12:01:41.47 -04:28:56.6 HIP 58558 18.85
2026-06-12 12:00 12:01:44.91 -04:28:44.9 HIP 58558 19.73
2026-06-13 00:00 12:01:48.48 -04:28:34.2 HIP 58558 20.64
2026-06-13 12:00 12:01:52.20 -04:28:24.5 HIP 58558 21.58
2026-06-14 00:00 12:01:56.06 -04:28:15.8 HIP 58558 22.55
2026-06-14 12:00 12:02:00.06 -04:28:08.1 HIP 58558 23.55
2026-06-15 00:00 12:02:04.21 -04:28:01.3 HIP 58558 24.59
2026-06-15 12:00 12:02:08.49 -04:27:55.5 HIP 58558 25.65
2026-06-16 00:00 12:02:12.91 -04:27:50.7 HIP 58558 26.75
2026-06-16 12:00 12:02:17.48 -04:27:46.9 HIP 58558 27.88
2026-06-17 00:00 12:02:22.18 -04:27:44.0 HIP 58558 29.04
2026-06-17 12:00 12:02:27.02 -04:27:42.1 HIP 58558 30.23
2026-06-18 00:00 12:02:32.00 -04:27:41.2 HIP 58829 30.02
2026-06-18 12:00 12:02:37.12 -04:27:41.3 HIP 58829 29.11
2026-06-19 00:00 12:02:42.37 -04:27:42.3 HIP 58829 28.22
2026-06-19 12:00 12:02:47.76 -04:27:44.2 HIP 58829 27.35
2026-06-20 00:00 12:02:53.29 -04:27:47.2 HIP 58829 26.51
2026-06-20 12:00 12:02:58.95 -04:27:51.1 HIP 58829 25.71
2026-06-21 00:00 12:03:04.75 -04:27:55.9 HIP 58829 24.95
2026-06-21 12:00 12:03:10.68 -04:28:01.7 HIP 58829 24.26
2026-06-22 00:00 12:03:16.74 -04:28:08.4 HIP 58829 23.64