Raman-scattered O vi Features in the Symbiotic Nova RR Telescopii

Kim

2022

ApJ

Self Cite

The accretion process in a typical S-type symbiotic star, targeting AG Draconis, is investigated through 3D hydrodynamical simulations using the FLASH code. Regardless of the wind velocity of the giant star, an accretion disk surrounding the white dwarf is always formed. In models where the wind is faster than the orbital velocity of the white dwarf, the disk size and accretion rate are consistent with the predictions under Bondi–Hoyle–Lyttleton (BHL) conditions. In slower-wind models, unlike the BHL predictions, the disk size does not grow, and the accretion rate increases to a considerably higher level, up to >20% of the mass-loss rate of the giant star. The accretion disk in our fiducial model is characterized by a flared disk with a radius of 0.16 au and a scale height of 0.03 au. The disk mass of ∼5 × 10−8 M ⊙ is asymmetrically distributed, with the density peak toward the giant star being about 50% higher than the density minimum in the disk. Two inflowing spiral features are clearly identified, and their relevance to the azimuthal asymmetry of the disk is pointed out. The flow in the accretion disk is found to be sub-Keplerian, at about 90% of the Keplerian speed, which indicates a caveat of overestimating the O vi emission region from the spectroscopy of Raman-scattered O vi features at 6825 and 7082 Å.

Section: Kinematics Of the Accretion Flowmentioning

confidence: 99%

Formation of the Asymmetric Accretion Disk from Stellar Wind Accretion in an S-type Symbiotic Star

Kim

2022

ApJ

Self Cite

“…In addition to the matter distribution around the WD component, the kinematic property of the accretion flow is essential to properly model the spectroscopic observations. Lee et al (2019) investigated the line profile of Raman-scattered O VI features at 6825 Å and 7082 Å based on the assumption that the O VI emission region of AG Dra is characterized by the Keplerian motion around the WD component (e.g., Heo et al 2016Heo et al , 2021). However, one may naturally expect that the real accretion flow should be much more complicated than a simple Keplerian motion due to the presence of the giant component and contribution from the thermal and turbulent motions.…”

Section: Kinematics Of the Accretion Flowmentioning

confidence: 99%

Formation of the Asymmetric Accretion Disk from Stellar Wind Accretion in an S-type Symbiotic Star

Lee,

Kim,

Lee

2022

Preprint

Self Cite

The accretion process in a typical S-type symbiotic star, targeting AG Draconis, is investigated through 3D hydrodynamical simulations using the FLASH code. Regardless of the wind velocity of the giant star, an accretion disk surrounding the white dwarf is always formed. In the wind models faster than the orbital velocity of the white dwarf, the disk size and accretion rate are consistent with the predictions under the Bondi-Hoyle-Lyttleton (BHL) condition. In slower wind models, unlike the BHL predictions, the disk size does not grow and the accretion rate increases to a considerably higher level, up to > 20% of the mass-loss rate of the giant star. The accretion disk in our fiducial model is characterized by a flared disk with a radius of 0.16 au and a scale height of 0.03 au. The disk mass of ∼ 5 × 10 −8 M is asymmetrically distributed with the density peak toward the giant star, being about 50% higher than the density minimum in the disk. Two inflowing spiral features are clearly identified and their relevance to the azimuthal asymmetry of disk is pointed out. The flow in the accretion disk is found to be sub-Keplerian with about 90% of the Keplerian speed, which indicates the caveat of overestimating the O VI emission region from spectroscopy of Raman-scattered O VI features at 6825 Å and 7082 Å.

Discovery of Raman-scattered C ii Lines in V366 Carinae with GHOST/Gemini South

Heo,

Jeong

2024

Res. Notes AAS

We report the detection of Raman-scattered C ii lines at 7023 and 7054 Å in the symbiotic star V366 Carinae using Gemini High-resolution Optical SpecTrograph (GHOST) at Gemini South. These faint features, originating from the C ii doublet at λλ1036 and 1037, are rare and have been detected in only two other symbiotic stars: V1016 Cygni and RR Telescopii. Our findings showcase the exceptional sensitivity of GHOST to detect subtle spectral features and open the door to comparative studies of Raman-scattered C ii features across these systems.