ExoClock

The Star
Simbad GAIA 2MASS	Qatar 4 DR2 385697172809355392 J00192622+4401395
RA	00:19:26.2245		DEC	+44:01:39.484
Parallax 3.011 mas		P.M. RA 0.985 mas/y		P.M. DEC -8.866 mas/y
Mag_V 13.6	Mag_R 13.68	Mag_I^* 12.636	Mag_J 12.03	Mag_H 11.631	Mag_K 11.519
Mag_G 13.411		Mag_{G_BP} 13.892		Mag_{G_RP} 12.783
^* calculated from GAIA magnitudes

Ephemeris - Not verified
Mallonn et al. 2019
Mid-time 2457872.4717 ± 0.0005 BJD_TDB
Period 1.80537 ± 4e-06 days
Transit Parameters
Alsubai et al. 2017
R_p/R_s 0.138 ± 0.003	a/R_s 7.1 +0.5 -0.5		i 87.5 +1.6 -1.6 deg
R_p/R_s 0.138 ± 0.003	e -		ω - deg
Depth_R^* 25.42 mmag		Duration^* 2.14 hours
^* calculated from the other parameters, using PyLightcurve
Limb Darkening Parameters
Alsubai et al. 2017
T_eff 5215.0 +50.0 -50.0 K	Log(g) 4.53 +0.06 -0.06 cm/s²		Fe/H 0.1 +0.08 -0.08 dex

ExoClock Status
Observing Priority Total Observations (Recent) O-C minutes Total Literature Mid-times		LOW 25 (11) -2.91±0.15 1

ExoClock Observations

Obs. Date	O-C (min)	Observer Observatory	Telescope Camera / Filter / Exp [s]
2020-11-18	-5.9 ± 0.9	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Lum / 120.0
2020-11-07	-6.5 ± 0.6	Lorenzo Betti Osservatorio Polifunzionale del Chianti	Ritchey-Chretien Moravian G4 - KAF 09000 / V / 90.0
2020-11-02	-5.4 ± 0.6	Taewoo Kim Deokheung Optical Astronomy Observatory	NYSC 1m Telescope FLI PL-16803 or PI SOPHIA-2048B / R / 120.0
2020-09-12	-4.8 ± 1.0	Manfred Raetz privat observatory Herges-Hallenberg	SCT 280 /1790 (Celestron C11 with reducer) Moravian Instruments G2-1600 / Clear / 120.0
2020-08-25	-3.5 ± 0.4	Anaël Wünsche Observatoire des Baronnies Provençales	Astelco2 ZWO ASI6200 / Clear / 120.0
2020-08-25	-4.6 ± 0.7	Alberto Tomatis Alto-Observatory	RC STL 6303 / Lum / 240.0
2020-08-25	-4.8 ± 1.0	Vojtěch Školník Hvezdarna Valasske Mezirici	Meade LX90 ACF Meade DSI II / Clear / 180.0
2020-08-25	-4.9 ± 0.9	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2020-07-27	-4.7 ± 1.3	Francois Regembal HRTobs	Astrosib RC360 SBIG STX 16803 / Lum / 60.0
2020-07-09	-1.0 ± 1.2	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2020-07-09	-4.7 ± 0.7	Marc Bretton Observatoire des Baronnies Provençales	Astelco 800mm ZWO ASI6200 / Clear / 120.0
2020-01-07	-3.8 ± 1.9	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2019-11-12	-3.4 ± 1.4	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2019-10-07	-3.3 ± 1.2	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2019-10-05	-0.7 ± 0.4	Anaël Wünsche Observatoire des Baronnies Provençales	Astelco FLIPL230 / Clear / 120.0
2019-10-05	-3.3 ± 0.7	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2019-09-17	-4.9 ± 1.2	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2019-08-21	-3.7 ± 1.3	Dim Stouraitis Galilaios	SCT SXVF-H9 Starlight-Xpress / R / 60.0
2019-07-23	-1.8 ± 0.9	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2019-01-20	-2.3 ± 1.2	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2019-01-02	0.4 ± 1.6	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2018-12-24	0.6 ± 0.9	Yves Jongen Rasteau Observatory	Plane Wave CDK 17" SBIG STXL 11002 / Clear / 120.0
2018-01-24	0.0 ± 0.4	Anaël Wünsche Observatoire des Baronnies Provençales	Astelco FLIPL230 / Lum / 120.0
2017-09-05	-1.8 ± 1.7	Marc Deldem Les Barres Observatory	Celestron C8 SBIG ST8-XME / Clear / 150.0
2016-12-30	1.6 ± 2.0	Claudio Lopresti Claudio Lopresti	Makutov-Cassegrain CCD Sbig ST8xme / R / 240.0

Qatar-4b

Discovered by: Alsubai et al. 2017