We present precise new V , I, and K-band photometry for the planetary transit candidate star 
OGLE-TR-82. Good seeing V -band images acquired at the VLT allows us to measure V = 20.6 in 
spite of the presence of a brighter neighbour about 1” away. This faint magnitude 
answers the question why it has not been possible to measure radial velocities for this 
object. One transit of this star is well defined in the light curves in the i-band obtained 
at GEMINI-South. The measurement of the transit allows to verify that this is not a false 
positive, to confirm the transit amplitude measured by OGLE, and to improve the ephemeris. 
The near-infrared photometry obtained at the ESO NTT yields K = 12.2 ± 0.1,
and V −K = 8.4±0.1, implying that this is a nearby M7V star, or a very reddened 
distant M-type red giant. Due to the extreme nature of this object, we have not yet been 
able to measure velocities for this star, but consider two different possible transit 
configurations. Based on the new data, the nearby M7V dwarf hypothesis yields a radius for 
the companion of Rp = 0.3 ± 0.1 RJ , i.e. the size of Neptune. The reddened giant hypothesis 
suggests a normal low mass main-sequence star for the companion. However, both scenarios are 
inconsistent with the transit length measured here, suggesting a more complicated system.
Near-IR spectroscopy finally shows that OGLE-TR-82 is a distant, reddened giant of spectral 
type M0III. Therefore, we discard the planetary nature of the companion, which is most 
likely a late M dwarf star. As a case study, this new kind of system that can mimick a 
planetary transit is a lesson to learn for future transit surveys.

Completed Title of the POSTER:
                   
Millimagnitude Photometry for Transiting Extrasolar Planetary Candidates: The Puzzle of the 
Extremely Red OGLE-TR-82 Primary Solved