400P/PANSTARRS

Metadata

Parameter Value
Designation 400P/PANSTARRS
Type P
Perihelion (tp_cal, UTC) 2021-02-09T22:37:16.553280Z
Orbit solution date (soln_date, UTC) 2024-10-05T23:12:48Z
Obs used 414
NEO -
M1 13.800
K1 12.250
PC 0.030
Discovery observation (MPC, UTC) 2020-09-10T09:07:24.096000Z
Discovery magnitude (MPC) 19.20 G
Discovery observatory (MPC) G96 · Mt. Lemmon Survey
Osculating Elements
Parameter Value
Epoch (epoch_cal, TDB) 2020-02-27.0000000
e 0.40901297
q (au) 2.104108
a (au) 3.560329
i (deg) 10.926393
Ω (om, deg) 176.405371
ω (w, deg) 238.711384
M (ma, deg) 308.805563

Magnitude

400P/PANSTARRS · Magnitude (Full range)

Scatter + Global Linear

$$ M_a = (11.776 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter Value
H0 11.776
n 6.000
gf 1.000
gb -1.000
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
2020-06-01 2020-08-29 +19.2128 -6.748
2020-08-29 2021-02-07 +8.6813 -3.045
2021-02-10 2022-02-24 +1.7883 -1.680

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 20:21:28.91 -08:05:29.6 HIP 100326 23.26
2026-05-12 12:00 20:21:35.42 -08:03:58.2 HIP 100326 22.71
2026-05-13 00:00 20:21:41.69 -08:02:27.5 HIP 100326 22.34
2026-05-13 12:00 20:21:47.73 -08:00:57.5 HIP 100326 22.15
2026-05-14 00:00 20:21:53.54 -07:59:28.2 HIP 100326 22.12
2026-05-14 12:00 20:21:59.11 -07:57:59.7 HIP 100326 22.25
2026-05-15 00:00 20:22:04.44 -07:56:32.0 HIP 100326 22.51
2026-05-15 12:00 20:22:09.53 -07:55:05.0 HIP 100326 22.90
2026-05-16 00:00 20:22:14.39 -07:53:38.8 HIP 100326 23.38
2026-05-16 12:00 20:22:19.00 -07:52:13.4 HIP 100326 23.95
2026-05-17 00:00 20:22:23.37 -07:50:48.8 HIP 100326 24.59
2026-05-17 12:00 20:22:27.51 -07:49:25.0 HIP 100326 25.28
2026-05-18 00:00 20:22:31.40 -07:48:02.0 HIP 100596 23.92
2026-05-18 12:00 20:22:35.04 -07:46:39.9 HIP 100596 22.45
2026-05-19 00:00 20:22:38.44 -07:45:18.6 HIP 100596 21.07
2026-05-19 12:00 20:22:41.60 -07:43:58.2 HIP 100596 19.79
2026-05-20 00:00 20:22:44.52 -07:42:38.7 HIP 100596 18.60
2026-05-20 12:00 20:22:47.18 -07:41:20.0 HIP 100596 17.53
2026-05-21 00:00 20:22:49.60 -07:40:02.2 HIP 100596 16.59
2026-05-21 12:00 20:22:51.78 -07:38:45.4 HIP 100596 15.78
2026-05-22 00:00 20:22:53.71 -07:37:29.5 HIP 100596 15.11
2026-05-22 12:00 20:22:55.39 -07:36:14.5 HIP 100596 14.61
2026-05-23 00:00 20:22:56.82 -07:35:00.4 HIP 100596 14.27
2026-05-23 12:00 20:22:58.00 -07:33:47.3 HIP 100596 14.10
2026-05-24 00:00 20:22:58.93 -07:32:35.1 HIP 100596 14.09
2026-05-24 12:00 20:22:59.62 -07:31:23.9 HIP 100596 14.24
2026-05-25 00:00 20:23:00.05 -07:30:13.7 HIP 100596 14.55
2026-05-25 12:00 20:23:00.23 -07:29:04.5 HIP 100596 14.99
2026-05-26 00:00 20:23:00.17 -07:27:56.3 HIP 100596 15.54
2026-05-26 12:00 20:22:59.84 -07:26:49.1 HIP 100596 16.20
2026-05-27 00:00 20:22:59.27 -07:25:42.9 HIP 100596 16.95
2026-05-27 12:00 20:22:58.45 -07:24:37.7 HIP 100596 17.78
2026-05-28 00:00 20:22:57.37 -07:23:33.6 HIP 100596 18.67
2026-05-28 12:00 20:22:56.04 -07:22:30.5 HIP 100596 19.62
2026-05-29 00:00 20:22:54.45 -07:21:28.6 HIP 100596 20.61
2026-05-29 12:00 20:22:52.61 -07:20:27.6 HIP 100596 21.65
2026-05-30 00:00 20:22:50.52 -07:19:27.8 HIP 100596 22.72
2026-05-30 12:00 20:22:48.17 -07:18:29.1 HIP 100596 23.83
2026-05-31 00:00 20:22:45.56 -07:17:31.4 HIP 100596 24.98
2026-05-31 12:00 20:22:42.70 -07:16:34.9 HIP 100596 26.15
2026-06-01 00:00 20:22:39.58 -07:15:39.5 HIP 100596 27.35
2026-06-01 12:00 20:22:36.21 -07:14:45.3 HIP 100596 28.58
2026-06-02 00:00 20:22:32.58 -07:13:52.2 HIP 100596 29.84