Multi-epoch detections of water ice absorption in edge-on disks around Herbig Ae stars: PDS 144N and PDS 453

Journal Article · Tue Jan 10 04:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/834/2/115· OSTI ID:22869522

Terada, Hiroshi ^[1]; Tokunaga, Alan T. ^[2]

---

1. Thirty-Meter Telescope Project, National Astronomical Observatory of Japan, 100 West Walnut, Suite 300, Pasadena, CA 91124 (United States)
2. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)

We report the multi-epoch detections of water ice in 2.8–4.2 μm spectra of two Herbig Ae stars, PDS 144N (A2 IVe) and PDS 453 (F2 Ve), which have an edge-on circumstellar disk. The detected water ice absorption is found to originate from their protoplanetary disks. The spectra show a relatively shallow absorption of water ice of around 3.1 μm for both objects. The optical depths of the water ice absorption are ∼0.1 and ∼0.2 for PDS 144N and PDS 453, respectively. Compared to the water ice previously detected in low-mass young stellar objects with an edge-on disk with a similar inclination angle, these optical depths are significantly lower. It suggests that stronger UV radiation from the central stars effectively decreases the water ice abundance around the Herbig Ae stars through photodesorption. The water ice absorption in PDS 453 shows a possible variation of the feature among the six observing epochs. This variation could be due to a change of absorption materials passing through our line of sight to the central star. The overall profile of the water ice absorption in PDS 453 is quite similar to the absorption previously reported in the edge-on disk object d216-0939, and this unique profile may be seen only at a high inclination angle in the range of 76°–80°.

• OSTI ID: 22869522
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 834; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ABUNDANCE
COMPARATIVE EVALUATIONS
COSMIC DUST
DETECTION
ICE
INCLINATION
MASS
PROTOPLANETS
SPECTRA
STARS
ULTRAVIOLET RADIATION