Title: A 80 au cavity in the disk around HD 34282 Author: G. van der Plas, F. Menard, H. Canovas, H. Avenhaus, S. Casassus, C. Cacares, L. Cieza, C. Pinte
Context: Large cavities in disks are important testing grounds for the mechanisms proposed to drive disk evolution and dispersion, such as dynamical clearing by planets and photo-evaporation. Aims: We aim to resolve the large cavity in the disk around HD 34282, such as has been predicted by previous studies modelling the spectral energy distribution Methods: Using ALMA band 7 observations we study HD 34282 with a spatial resolution of 0.10\arcsec x 0.17\arcsec at 345 GHz. Results: We resolve the disk around HD 34282 into a ring between 0.24\arcsec and 1.15\arcsec (78 and 374 au adopting a distance of 325 pc). The emission in this ring shows azimuthal asymmetry centered at a radial distance of 0.46\arcsec and a position angle of 135 degrees and an azimuthal FWHM of 51 degrees. We detect CO emission both inside the disk cavity and as far out as 2.7 times the radial extent of the dust emission. Conclusions: Both the large disk cavity and the azimuthal structure in the disk around HD 34282 can be explained by the presence of a 50 jupiter mass brown dwarf companion at a separation of ~ 0.1\arcsec.
Title: MOST observations of the Herbig Ae delta-Scuti star HD 34282 Authors: M. P. Casey, K. Zwintz, D. B. Guenther, W. W. Weiss, P. J. Amado, D. Díaz-Fraile, E. Rodriguez, R. Kuschnig, J. M. Matthews, A. F. J. Moffat, J. F. Rowe, S. M. Rucinski, D. Sasselov
MOST observations and model analysis of the Herbig Ae star HD 34282 (V1366 Ori) reveal delta-Scuti pulsations. 22 frequencies are observed, 10 of which confirm those previously identified by Amado et al. (2006), and 12 of which are newly discovered in this work. We show that the weighted-average frequency in each group fits the radial p-mode frequencies of viable models. We argue that the observed pulsation spectrum extends just to the edge to the acoustic cut-off frequency and show that this also is consistent with our best-fitting models.