– 27 – $^{10}$available at http://irsa.ipac.caltech.edu/data/SPITZER/C2D/index cutouts.html $^{11}$http://ssc.spitzer.caltech.edu/mips/apercorr/ luminosities remain more poorly constrained. Only 9 of our 34 targets have ( 5- σ or better) detections at 70 µ m listed in the Cores to Disks catalog. For the rest of the objects, we have obtained 5- σ upper limits, from the noise of the 70 µ m images at the location of the targets, in order to fill the gap in their SEDs between 24 µ m and the millimeter. In particular, we used 120 ′′ × 120 ′′ cut outs 10 of the Ophichus mosaic created by the Cores to Disks project from the “filtered” Basic Calibrated Data. We calculated the noise as 1- σ = 2 × 1.7(rms$_{sky}$) √ N , where rms$_{sky}$ is the flux rms (in mJy) of an annulus centered on the source with an inner and outer radius of 40 and 64 $^{′′}$, respectively. N is the number of (4 $^{′′}$) pixels in a circular aperture of 16′′ in radius, and 1.7 is the aperture correction appropriate for such sky annulus and aperture size $^{11}$. The factor of 2 accounts for the fact that the images we use have been resampled to pixels that are half the linear size of the original pixels, artificially reducing the noise of the images (by √ N$_{res}$ $_{N$_{orig}$}$, where N$_{res}$ and N$_{orig}$ are, respectively, the number of resampled and original pixels in the sky annulus). The LOG(L$_{D}$/L$_{∗}$) values for our transition disk sample, ranging from -4.1 to -1.5 are listed in Table 3. As most of the luminosity of a disk extending inward to the dust sublimation temperature is emitted in the near-IR, L$_{D}$/L$_{∗}$ is a very strong function of λ$_{turn}$$_{−}$$_{off}$ : the shorter the λ$_{turn}$$_{−}$$_{off}$ wavelength, the higher the fractional disk luminosity. For objects with λ$_{turn}$$_{−}$$_{off}$ < 8.0 µ m, the 70 µ m flux represent only a minor contribution to the total disk luminosity. On the other hand, objects with with λ$_{turn}$$_{−}$$_{off}$ = 8.0 µ m (i.e., objects with significant excess at 24 µ m only) have much lower L$_{D}$/L$_{∗}$ values, and the 70 µ m emission becomes a much larger fraction of the total disk luminosity. As a result, the L$_{D}$/L$_{∗}$ values of objets with λ$_{turn}$$_{−}$$_{off}$ = 8.0 µ m and no 70 µ m detections should be considered upper limits.