exoclock

WASP-81b (LOW)

Discovered by: Triaud et al. 2017

The Star
Simbad
GAIA
2MASS		 WASP-81
DR2 4244243354278985472
J20164989+0317385
RA 20:16:49.8900 DEC +03:17:38.454
Parallax
2.482 mas		 P.M. RA
27.196 mas/y		 P.M. DEC
-15.319 mas/y
MagV
12.47		 MagR
12.37		 MagI
11.7		 MagJ
11.263		 MagH
10.913		 MagK
10.892
MagG
12.333		 MagGBP
12.679		 MagGRP
11.832
*Calculated from GAIA magnitudes.

Ephemeris - Verified True
Kokori et al. 2025
Mid-time
2458249.23761 ± 0.00023 BJDTDB
Period
2.7164845 ± 3.9e-07 days
Transit Parameters
Triaud et al. 2017
Rp/Rs
0.112 ± 0.0012		 a/Rs
6.56 +0.13 -0.16
 i
88.7 +0.9 -0.9 deg
e
-		 ω
- deg
DepthR*
16.66 mmag		 Duration*
3.5 hours
*Calculated from the other parameters, using PyLightcurve.
**Adjusted based on the space observations.

Limb Darkening Parameters
Triaud et al. 2017
Teff
5870.0 +120.0 -120.0 K
 Log(g)
4.26 +0.02 -0.03 cm/s2
 Fe/H
-0.36 +0.14 -0.14 dex
ExoClock Status
Observing Priority LOW
Minimum aperture 6.41"
Total Observations (Recent) 36 (4)
O-C 0.25 ± 0.89 minutes
ExoClock Observations (Recent) 30 (4)
Space Observations (Recent) 5 (0)
ETD Observations (Recent) 0 (0)
Literature Mid-times (Recent) 1 (0)
Kepler Rp/Rs -
TESS Rp/Rs 0.1121 ± 0.0011

WASP-81b


ExoClock Observations
Planet
Observation Date		 Observer
Observatory		 Telescope
Camera / Filter / Exp [s]		 O-C
minutes
WASP-81b (LOW)
2025-09-30		christian PANTACCHINI
Observatoire de BENAYES		Newton
MORAVIAN G3 kai-11000 / Lum / 60.0		-3.03 ± 3.31
WASP-81b (LOW)
2025-09-11		Moises Portillo
Elguin		GSO
Omegon vetec16000c / AstrodonExoPlanet-BB / 180.0		-0.88 ± 3.31
WASP-81b (LOW)
2025-09-11		Mark van der Grijp
Raspay Observatory		C9.25 HD
ZWO2600 MM Pro / Lum / 180.0		-2.75 ± 2.02
WASP-81b (LOW)
2025-08-13		Giovanni Calapai
Home Astronomical Observatory		Celestron 11 Schmidt-Cassegrain
Atik 314L+ / Clear / 90.0		3.19 ± 1.58
WASP-81b (LOW)
2024-08-24		Paolo Arcangelo Matassa
P:M.P.H.R. Deep Sky (K81)		Ritchey Chretien 40cm-F5.3
CCD ICX453AQ / Lum / 90.0		-3.45 ± 5.62
WASP-81b (LOW)
2024-07-25		Ian Sharp
PixelSkies		Celestron C11 Edge HD
Starlight Xpress Trius Pro SX694 / R / 90.0		3.79 ± 3.02
WASP-81b (LOW)
2024-07-25		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		-1.39 ± 2.16
WASP-81b (LOW)
2024-06-17		Zlatko Orbanić
Explorer		Newton Truss 254mm F/3.8
Atik 414 Ex Mono / rpr / 50.0		0.74 ± 3.31
WASP-81b (LOW)
2023-08-26		Paolo Arcangelo Matassa
P:M.P.H.R. Deep Sky (K81)		Ritchey Chretien 40cm-F5.3
CCD ICX453AQ / Lum / 60.0		-1.69 ± 3.02
WASP-81b (LOW)
2023-08-16		Adrian Jones
Private Observatory (I64)		Meade ACF 30cm
QSI 583 / R / 150.0		-2.93 ± 2.02
WASP-81b (LOW)
2023-07-27		Giovanni Calapai
Home Astronomical Observatory		Celestron 11 Schmidt-Cassegrain
Atik 314L+ / Clear / 100.0		-1.5 ± 1.58
WASP-81b (LOW)
2022-08-16		David Arnot
OSO PIRATE		PlaneWave Instruments CDK24 24 inch (610 mm) f/6.5 Corrected Dall-Kirkham Astrograph
FLI ProLine KAF-16803 / R / 55.0		-3.76 ± 1.44
WASP-81b (LOW)
2022-08-06		Yves Jongen
Deep Sky Chile		Plane Wave CDK 17"
Moravian 4G / Lum / 120.0		0.61 ± 2.74
WASP-81b (LOW)
2022-07-12		Chiahui Wang
NTNU ES Observatory		RCOS 16" w/CCDT67 f/5.4
Atik One 6 / R / 30.0		-3.76 ± 3.17
WASP-81b (LOW)
2022-07-09		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		0.68 ± 1.73
WASP-81b (LOW)
2022-06-29		David Arnot
OSO PIRATE		PlaneWave Instruments CDK24 24 inch (610 mm) f/6.5 Corrected Dall-Kirkham Astrograph
FLI ProLine KAF-16803 / R / 50.0		3.61 ± 0.76
WASP-81b (LOW)
2021-07-29		Adam Popowicz
Observatory Pyskowice		RC12" GSO
ASI ZWO 1600 MM / ATIK 11000M / R / 120.0		1.73 ± 1.87
WASP-81b (LOW)
2021-07-29		Dim Stouraitis
Galilaios		SCT
SXVF-H9 Starlight-Xpress / R / 60.0		-0.72 ± 2.74
WASP-81b (LOW)
2021-07-29		Carmelo Falco
GALHassin Robotic Telescope 2 (GRT2)		Giacometti-Fogale RC16
Andor Apogee Aspen CG16M / gpr / 90.0		-1.29 ± 2.59
WASP-81b (LOW)
2021-07-29		Carmelo Falco
GAL Hassin Robotic Telescope 2 (GRT2) - Multiband		Giacometti-Fogale RC16 - 2
Andor Apogee Aspen CG16M / R / 90.0		-4.46 ± 1.58
WASP-81b (LOW)
2021-07-29		Paolo Arcangelo Matassa
P:M.P.H.R. Deep Sky (K81)		Ritchey Chretien 40cm-F5.3
CCD ICX453AQ / Clear / 120.0		-7.77 ± 4.32
WASP-81b (LOW)
2021-07-27		Yves Jongen
Deep Sky Chile		Plane Wave CDK 17"
Moravian 4G / Lum / 120.0		1.13 ± 1.01
WASP-81b (LOW)
2021-07-10		Adam Popowicz
Observatory Pyskowice		RC12" GSO
ASI ZWO 1600 MM / ATIK 11000M / R / 119.0		-5.19 ± 2.74
WASP-81b (LOW)
2021-07-08		Anaël Wünsche
El Sauce Observatory		CDK Planewave Chili
Moravian G4 16k / Lum / 120.0		0.4 ± 0.58
WASP-81b (LOW)
2021-06-27		Yves Jongen
Deep Sky Chile		Plane Wave CDK 17"
Moravian 4G / R / 120.0		1.17 ± 1.58
WASP-81b (LOW)
2020-08-08		Phil Evans
El Sauce		Planewave CDK14
SBIG STT 1603-3 / R / 120.0		-0.19 ± 1.3
WASP-81b (LOW)
2020-08-08		Yves Jongen
Deep Sky Chile		Plane Wave CDK 17"
Moravian 4G / R / 120.0		-2.49 ± 1.01
WASP-81b (LOW)
2020-07-28		Yves Jongen
Deep Sky Chile		Plane Wave CDK 17"
Moravian 4G / R / 120.0		-1.0 ± 1.15
WASP-81b (LOW)
2020-07-11		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-1.27 ± 1.15
WASP-81b (LOW)
2020-07-11		Danilo Sedita
Osservatorio Sedita Castrofilippo		RC GSO 14"
Moravian G2-1600 / R / 60.0		-2.42 ± 1.87

Space Observations
Planet
Observation Date		 Mission O-C
minutes
WASP-81b (LOW)
2022-08-03		TESS1.93 ± 1.43
WASP-81b (LOW)
2022-07-26		TESS-2.07 ± 1.58
WASP-81b (LOW)
2022-07-23		TESS-0.33 ± 1.22
WASP-81b (LOW)
2022-07-12		TESS-0.45 ± 1.44
WASP-81b (LOW)
2022-07-09		TESS4.13 ± 1.44

Literature Mid-times
Planet
Observation Date		 Reference O-C
minutes
2012-09-25 Triaud et al. 2017 0.1 ± 0.33
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