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New photometric observations of the hierarchical eclipsing TY CrA system weretaken in the optical with VYSOS6 and in the near-IR with SOFI and REMIR. Theyare the first observations showing the deep eclipse minimum of the pre-mainsequence secondary in the near-IR. For the first time, the secondary minimumcan be reliably used in the calculation of the O-C diagram of TY CrA. By now,the O-C diagram can be studied on a time basis of about two decades. Weconfirm, that the O-C diagram cannot be explained by the spectroscopictertiary. For the first time, the light curve of the inner eclipsing binary isanalysed in both optical and near-IR bands simultaneously. In combination withalready published spectroscopic elements, precise absolute dimensions andmasses of the primary and the secondary component are obtained using the ROCHEcode. The inclusion of the near-IR data puts strong constraints on the thirdlight which is composed of the reflection nebula, the spectroscopic tertiaryand a visual fourth component. The absolute parameters of the inner eclipsingbinary agree very well with previous work except of the primary radius(1.46+/-0.15 Rsun) and luminosity (40+/-10 Lsun) which are clearly smaller.While the parameters of the secondary are well understood when assuming an ageof about 3-5 Myrs, the primary seems considerably undersized. Low metallicitycannot explain the parameters of the primary.

The eclipsing binary TY CrA revisited: What near-IR light curves tell us