SPIRAL ARMS IN THE DISK OF HD 142527 FROM CO EMISSION LINES WITH ALMA

Journal Article · Thu Apr 10 04:00:00 EDT 2014 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/785/1/L12· OSTI ID:22365907

Christiaens, V.; Casassus, S.; Perez, S.; Van der Plas, G. ^[1]

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1. Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile)

In view of both the size of its gap and the previously reported asymmetries and near-infrared spiral arms, the transition disk of the Herbig Fe star HD 142527 constitutes a remarkable case study. This paper focuses on the morphology of the outer disk through ALMA observations of {sup 12}CO J = 2-1, {sup 12}CO J = 3-2, and {sup 13}CO J = 2-1. Both {sup 12}CO J = 2-1 and {sup 12}CO J = 3-2 show spiral features of different sizes. The innermost spiral arm (S1) is a radio counterpart of the first near-infrared spiral observed by Fukagawa, but it is shifted radially outward. However, the most conspicuous CO spiral arm (S2) lies at the outskirts of the disk and has not been detected before. It corresponds to a cold density structure, with both brightness and excitation temperatures of order 13±2 K and conspicuous in the {sup 12}CO J = 2-1 peak-intensity map, but faint in {sup 12}CO J = 3-2. There is also a faint counterarm (S3), at a point-symmetric location of S2 with respect to the star. These three spirals are modeled separately with two different formulae that approximate the loci of density maxima in acoustic waves due to embedded planets. S1 could be fit relatively well with these formulae, compared to S2 and S3. Alternative scenarios such as gravitational instability or external tidal interaction are discussed. The impact of channelization on spectrally and spatially resolved peak intensity maps is also briefly addressed.

• OSTI ID: 22365907
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 785; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
APPROXIMATIONS
ASYMMETRY
BRIGHTNESS
CARBON MONOXIDE
COMPARATIVE EVALUATIONS
DENSITY
EXCITATION
GRAVITATIONAL INSTABILITY
HERBIG-HARO OBJECTS
MORPHOLOGY
NEAR INFRARED RADIATION
PLANETS
PROTOPLANETS
SOUND WAVES
STARS