Millimagnitude optical photometry for the transiting planetary candidate OGLE-TR-109

摘要: We present precise V-band photometry for the low-amplitude transit candidate star OGLE-TR-109. This is an extreme case among transiting candidates found by OGLE group because of early spectral type (F0 V), low amplitude (AI = 0.008 mag), and very short period (P 0.58909 days) orbiting companion. Using difference image photometry, we are able to achieve millimagnitude errors in individual data points. One this well defined our light curve. confirms detection rules out possibility a false positive. The measurement allows us refine (AV 0.006 ± 0.001 mag) ephemerides interesting system, as radius possible companion (RP 0.90RJ 0.09RJ) inclination orbit (i 77° 5°). Two other transits observed at lower S/N confirm system measured OGLE. There no evidence blend F-type main-sequence with redder eclipsing binary or secondary observations. absence ellipsoidal modulation curve primary low-mass brown dwarf M > 14MJ 8MJ. remaining possibilities OGLE-TR-109 between bluer star, new extrasolar planet.