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High angular-resolution infrared imaging and spectra of the carbon-rich AGB star V Hya

Published online by Cambridge University Press:  30 December 2019

Raghvendra Sahai ,
Jayadev Rajagopal ,
Kenneth Hinkle Open the ORCID record for Kenneth Hinkle [Opens in a new window] ,
Richard Joyce Open the ORCID record for Richard Joyce [Opens in a new window]  and
Mark Morris
Raghvendra Sahai
Affiliation:
Jet Propulsion Laboratory, MS 183-900, California Institue of Technology, Pasadena, CA 91109, USA email: raghvendra.sahai@jpl.nasa.gov
Jayadev Rajagopal
Affiliation:
National Optical Astronomy Observatory, 950 N. Cherry Ave, Tucson, AZ 85719, USA
Kenneth Hinkle
Affiliation:
National Optical Astronomy Observatory, 950 N. Cherry Ave, Tucson, AZ 85719, USA
Richard Joyce
Affiliation:
National Optical Astronomy Observatory, 950 N. Cherry Ave, Tucson, AZ 85719, USA
Mark Morris
Affiliation:
Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA
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Abstract

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The carbon-rich AGB star V Hya is believed to be in the very brief transition phase between the AGB and a planetary nebula (PN). Using HST/STIS, we previously found a high-velocity (> 200 kms−1) jet or blob of gas ejected only a few years ago from near (< 0.3 arcsec or 150 AU) the star (Sahai et al. 2003, Sahai et al. 2016). From multi-epoch high-resolution spectroscopy we found time-variable high-velocity absorption features in the CO 4.6 μm vibration-rotation lines of V Hya (Sahai et al. 2009). Modeling shows that these are produced in compact clumps of outflowing gas with significant radial temperature gradients consistent with strong shocks. Here, we present very high resolution (∼100 milliarcsecond) imaging of the central region of V Hya using the coronagraphic mode of the Gemini Planet Imager (GPI) in the 1 μm band and spectral-spatial imaging of 4.6 μm CO 1-0 transitions using the Phoenix spectrometer. We report the detection of a compact central dust disk from GPI, and molecular emission from the Phoenix observations at relatively larger scales. We discuss models for the central structures in V Hya, in particular disks and outflows, using these and complementary images in the optical and radio.

Keywords

stars: AGB and post-AGBinstrumentation: High angular resolutionISM: planetary nebulae: general
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 14 , Symposium S343: Why Galaxies Care About AGB Stars: A Continuing Challenge through Cosmic Time , August 2018 , pp. 495 - 497
Copyright
© International Astronomical Union 2019 

References

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