The circumstellar dust disk of the Herbig Ae star AB Aurigae has been found to exhibit complex
spiral-like structures in the near-IR. We present maps of the disk in both $^{12}$CO (3-2) and dust continuum at
345~GHz with the SMA at an angular resolution of $1''\!\!.0$ $\times$ $0.7''\!\!$~(144AU $\times$ 100AU). The
continuum emission traces a dust disk of a maximum overall dimension of 450AU (FWHM) with a central depression,
and exhibits several distinct peaks that appear to coincide with bright features in the near-IR image, in
particular the brightest spiral arm. The CO emission traces a rotating gas disk of size 530AU $\times$ 330AU
with a deprojected maximum velocity of 2.8~km~s$^{-1}$ at 450~AU. In contrast to dust, the gas disk is not
entirely devoid of material at its center. Furthermore, the CO emission in several velocity channels traces the
spiral-like structure seen in the IR. However, the spatial-kinematic structure of the CO emission cannot be fit
by a disk in Keplerian rotation, and the spiral arms appear to exhibit an excess outward radial motion. The disk
of AB Aur is therefore quite different from the Keplerian disks seen around many lower mass T Tauri and Herbig
Ae stars. We constrain the Toomre's Q parameter to investigate the possibility that the disk is gravitationally
unstable, as well as discuss the effect of a giant planet perturbation to excite the spiral pattern seen in the
disk of AB Aur.

Acke et al. A&A 422, 621 (2004)
Beckwith et al. In Protostars and Planets III, pp. 521 (1993)
Beckwith et al. ApJ 402, 280 (1990)
Carroll et al. An Instroduction to Modern Astrophysics (1996)
Chen et al. ApJ 591, 267 (2003)
Corder et al. ApJL 622, 133 (2005)
DeWarf et al. ApJ 590, 357 (2003)
Eisner et al. ApJ 588, 360 (2003)
Fukagawa et al. ApJL 605, 53 (2004)
Grady et al. ApJL 523, 151 (1999)
Ho et al. ApJL 616, 1 (2004)
Holland et al. Nature 392, 788 (1998)
Lagrange et al. in Protostar and Planets IV (2000)
Leinert et al. ASPC 155 (1994)
Lissauer et al. ARAA 31, 129 (1993)
Mannings et al. MNRAS 271, 587 (1994)
Mannings et al. ApJ 490, 792 (1997)
Natta et al. in Protostars and Planets, 559 (2000)
Pietu et al. ApJ (in press 2005)
Pollack et al. ApJ 421, 615 (1994)
Prato et al. ApJ 549, 590 (2001)
Scoville et al. PASP 105, 1482 (1993)
Thi et al. ApJ 561, 1074 (2001)
van den Ancker et al. A&A 324, L33 (1997)
Wilner et al. ApJL 569, L115 (2002)
Zuckerman ARAA 39, 549 (2001)