* Astronomy

Title: PDS 144: The First Confirmed Herbig Ae - Herbig Ae Wide Binary
Authors: J. B. Hornbeck, C. A. Grady, M. D. Perrin, J. P. Wisniewski, B. M. Tofflemire, A. Brown, J. A. Holtzman, K. Arraki, K. Hamaguchi, B. Woodgate, R. Petre, B. Daly, N. A. Grogin, D. G. Bonfield, G. M. Williger, J. T. Lauroesch

PDS 144 is a pair of Herbig Ae stars that are separated by 5.35" on the sky. It has previously been shown to have an A2Ve Herbig Ae star viewed at 83° inclination as its northern member and an A5Ve Herbig Ae star as its southern member. Direct imagery revealed a disk occulting PDS 144 N - the first edge-on disk observed around a Herbig Ae star. The lack of an obvious disk in direct imagery suggested PDS 144 S might be viewed face-on or not physically associated with PDS 144 N. Multi-epoch Hubble Space Telescope imagery of PDS 144 with a 5 year baseline demonstrates PDS 144 N & S are comoving and have a common proper motion with TYC 6782-878-1. TYC 6782-878-1 has previously been identified as a member of Upper Sco sub-association A at d = 145 ±2 pc with an age of 5-10 Myr. Ground-based imagery reveals jets and a string of Herbig-Haro knots extending 13' (possibly further) which are aligned to within 7° ±6° on the sky. By combining proper motion data and the absence of a dark mid-plane with radial velocity data, we measure the inclination of PDS 144 S to be i = 73° ±7°. The radial velocity of the jets from PDS 144 N & S indicates they, and therefore their disks, are misaligned by 25° ±9°. This degree of misalignment is similar to that seen in T Tauri wide binaries.

Read more (2129kb, PDF)