R. Sahai
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View article: Evidence for the Keplerian orbit of a close companion around a giant star
Evidence for the Keplerian orbit of a close companion around a giant star Open
View article: Appendices to "ATOMIUM: Continuum emission and evidence of dust enhancement from binary motion"
Appendices to "ATOMIUM: Continuum emission and evidence of dust enhancement from binary motion" Open
Appendices A through H to the A&A publication "ATOMIUM: Continuum emission and evidence of dust enhancement from binary motion" by T. Danilovich, N. Samaratunge, Y. Mori, A. M. S. Richards, A. Baudry, S. Etoka, M. Montargès, P. Kervella, I…
View article: Discovery of SiC and Iron Dust around AGB Stars in the Very Metal-poor Sextans a Dwarf Galaxy with JWST: Implications for Dust Production at High Redshift
Discovery of SiC and Iron Dust around AGB Stars in the Very Metal-poor Sextans a Dwarf Galaxy with JWST: Implications for Dust Production at High Redshift Open
Low-resolution infrared spectroscopy from JWST confirms the presence of SiC and likely metallic iron dust around asymptotic giant branch (AGB) stars in the Sextans A dwarf galaxy, which has a metallicity ∼1%–7% Z ⊙ . While metal-poor carbo…
View article: Discovery of SiC and Iron Dust Around AGB Stars in the very Metal-Poor Sextans A Dwarf Galaxy with JWST: Implications for Dust Production at High Redshift
Discovery of SiC and Iron Dust Around AGB Stars in the very Metal-Poor Sextans A Dwarf Galaxy with JWST: Implications for Dust Production at High Redshift Open
Low-resolution infrared spectroscopy from JWST confirms the presence of SiC and likely metallic iron dust around asymptotic giant branch (AGB) stars in the Sextans A dwarf galaxy, which has a metallicity ~1%-7% Z_sun. While metal-poor carb…
View article: Exploring circumstellar chemistry in X-ray emitting AGB stars
Exploring circumstellar chemistry in X-ray emitting AGB stars Open
Aims . Our goal is to characterise the chemistry and physical conditions of the circumstellar envelopes (CSEs) of Asymptotic Giant Branch (AGB) binary candidate stars with UV-excess and X-ray emission. In particular, our aim is to identify…
View article: <i>JWST</i> observations of the Ring Nebula (NGC 6720) – II. PAH emission
<i>JWST</i> observations of the Ring Nebula (NGC 6720) – II. PAH emission Open
Polycyclic aromatic hydrocarbons (PAHs) and carbonaceous dust have been observed in clumpy circumstellar environments, yet their formation and evolutionary pathways in such environments remain elusive. We aim to characterize the PAH emissi…
View article: An accreting dwarf star orbiting the S-type giant star <i>π</i><sup>1</sup> Gru
An accreting dwarf star orbiting the S-type giant star <i>π</i><sup>1</sup> Gru Open
Context. At the end of their lives, low- to intermediate-mass stars reach the asymptotic giant branch (AGB), during which their photospheres expand by up to several hundred times and strong stellar winds develop. These changes lead to vari…
View article: JWST Observations of the Ring Nebula (NGC 6720). III. A Dusty Disk around Its Central Star
JWST Observations of the Ring Nebula (NGC 6720). III. A Dusty Disk around Its Central Star Open
The planetary nebula NGC 6720, also known as the “Ring Nebula,” is one of the most iconic examples of nearby planetary nebulae whose morphologies present a challenge to our theoretical understanding of the processes that govern the deaths …
View article: Erratum: “The Structure of the Molecular Envelope of the Ring Nebula (NGC 6720)” (2025, ApJ, 981, 46)
Erratum: “The Structure of the Molecular Envelope of the Ring Nebula (NGC 6720)” (2025, ApJ, 981, 46) Open
View article: Testing the bloated star hypothesis in the massive young stellar object IRAS 19520+2759 through optical and infrared variability
Testing the bloated star hypothesis in the massive young stellar object IRAS 19520+2759 through optical and infrared variability Open
Using optical time series with Telescopi Joan Oró (TJO), Gaia, TESS, and NEOWISE archival data, we performed a variability study on the candidate bloated massive young stellar object (MYSO) IRAS 19520+2759. This is the first time that a bl…
View article: The Structure of the Molecular Envelope of the Ring Nebula (NGC 6720)
The Structure of the Molecular Envelope of the Ring Nebula (NGC 6720) Open
We present the first interferometric imaging of molecular line emission from the Ring Nebula, NGC 6720, in the form of Submillimeter Array (SMA) observations of CO J = 2 → 1 emission. The SMA 12 CO(2–1) mapping data, with ∼3″ spatial resol…
View article: Molecular Distributions and Abundances in the Binary-shaped Outflow of V Hya
Molecular Distributions and Abundances in the Binary-shaped Outflow of V Hya Open
Binaries are known to play a key role in the mass loss and dynamical environments of evolved stars. Stellar and substellar companion interactions produce complex wind morphologies including rotating/expanding disks, bipolar outflows, and s…
View article: The Structure of the Molecular Envelope of the Ring Nebula (NGC 6720)
The Structure of the Molecular Envelope of the Ring Nebula (NGC 6720) Open
We present the first interferometric imaging of molecular line emission from the Ring Nebula, NGC~6720, in the form of Submillimeter Array (SMA) observations of CO $J=2\rightarrow 1$ emission. The SMA $^{12}$CO(2--1) mapping data, with $\s…
View article: ALMA observations of CO isotopologues towards six obscured post-asymptotic giant branch stars
ALMA observations of CO isotopologues towards six obscured post-asymptotic giant branch stars Open
Context. Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB) when an efficient mass-loss process removes a significant fraction of their initial mass. For most sources, this mass-loss process relies on the int…
View article: ALMA observations of CO isotopologues towards six obscured post-AGB stars
ALMA observations of CO isotopologues towards six obscured post-AGB stars Open
Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB), when an efficient mass-loss process removes a significant fraction of their initial mass. A substantial increase in the mass-loss rate at the end of the AGB…
View article: Chemistry in the GG Tau A Disk: Constraints from H<sub>2</sub>D<sup>+</sup>, N<sub>2</sub>H<sup>+</sup>, and DCO<sup>+</sup> High Angular Resolution ALMA Observations
Chemistry in the GG Tau A Disk: Constraints from H<sub>2</sub>D<sup>+</sup>, N<sub>2</sub>H<sup>+</sup>, and DCO<sup>+</sup> High Angular Resolution ALMA Observations Open
Resolved molecular line observations are essential for gaining insight into the physical and chemical structure of protoplanetary disks, particularly in cold, dense regions where planets form and acquire their chemical compositions. Howeve…
View article: CO emission survey of asymptotic giant branch stars with ultraviolet excesses <i>(Corrigendum)</i>
CO emission survey of asymptotic giant branch stars with ultraviolet excesses <i>(Corrigendum)</i> Open
View article: Molecular Distributions and Abundances in the Binary-Shaped Outflow of V Hya
Molecular Distributions and Abundances in the Binary-Shaped Outflow of V Hya Open
Binaries are known to play a key role in the mass loss and dynamical environments of evolved stars. Stellar and sub-stellar companion interactions produce complex wind morphologies including rotating/expanding disks, bipolar outflows, and …
View article: Temporal Changes in the Infrared Spectra of Magellanic Carbon Stars
Temporal Changes in the Infrared Spectra of Magellanic Carbon Stars Open
The Medium-Resolution Spectrometer on the Mid-Infrared Instrument on the JWST obtained spectra of three carbon stars in the Large Magellanic Cloud. Two of the spectra differ significantly from spectra obtained ∼16–19 years earlier with the…
View article: ALMA Detection of Masers and Dasars in the Hydrogen Recombination Lines of the Planetary Nebula Mz3
ALMA Detection of Masers and Dasars in the Hydrogen Recombination Lines of the Planetary Nebula Mz3 Open
The hydrogen recombination lines H30 α , H40 α , H42 α , H50 β , and H57 γ and the underlying bremsstrahlung continuum emission were detected with ALMA in the bipolar nebula Mz3. The source was not spatially resolved, but the velocity prof…
View article: A Dust-Scattering Model for M1-92: A Revised Estimate of the Mass Distribution and Inclination
A Dust-Scattering Model for M1-92: A Revised Estimate of the Mass Distribution and Inclination Open
Preplanetary nebulae (PPNe) are formed from mass-ejecting late-stage AGB stars. Much of the light from the star gets scattered or absorbed by dust particles, giving rise to the observed reflection nebula seen at visible and near-IR wavelen…
View article: Distance Estimate Method for Asymptotic Giant Branch Stars Using Infrared Spectral Energy Distributions
Distance Estimate Method for Asymptotic Giant Branch Stars Using Infrared Spectral Energy Distributions Open
We present a method to estimate distances to asymptotic giant branch (AGB) stars in the Galaxy, using spectral energy distributions (SEDs) in the near- and mid-infrared. By assuming that a given set of source properties (initial mass, stel…
View article: Distance estimate method for Asymptotic Giant Branch stars using Infrared Spectral Energy Distributions
Distance estimate method for Asymptotic Giant Branch stars using Infrared Spectral Energy Distributions Open
We present a method to estimate distances to Asymptotic Giant Branch (AGB) stars in the Galaxy, using spectral energy distributions (SEDs) in the near- and mid-infrared. By assuming that a given set of source properties (initial mass, stel…
View article: The Molecular Exoskeleton of the Ring-like Planetary Nebula NGC 3132
The Molecular Exoskeleton of the Ring-like Planetary Nebula NGC 3132 Open
We present Submillimeter Array (SMA) mapping of 12 CO J = 2 → 1, 13 CO J = 2 → 1, and CN N = 2 → 1 emission from the ring-like planetary nebula NGC 3132, one of the subjects of JWST Early Release Observation near-infrared imaging. The ∼5″ …
View article: The Molecular Exoskeleton of the Ring-like Planetary Nebula NGC 3132
The Molecular Exoskeleton of the Ring-like Planetary Nebula NGC 3132 Open
We present Submillimeter Array (SMA) mapping of $^{12}$CO $J=2\rightarrow 1$, $^{13}$CO $J=2\rightarrow 1$, and CN $N=2\rightarrow 1$ emission from the Ring-like planetary nebula (PN) NGC 3132, one of the subjects of JWST Early Release Obs…
View article: CO emission survey of asymptotic giant branch stars with ultraviolet excesses
CO emission survey of asymptotic giant branch stars with ultraviolet excesses Open
Context . The transition from the spherically symmetric envelopes around asymptotic giant branch (AGB) stars to the asymmetric morphologies observed in planetary nebulae is still not well understood, and the shaping mechanisms are a subjec…
View article: CO emission survey of asymptotic giant branch stars with ultraviolet excesses
CO emission survey of asymptotic giant branch stars with ultraviolet excesses Open
Context. The transition from the spherically symmetric envelopes around asymptotic giant branch (AGB) stars to the asymmetric morphologies observed in planetary nebulae is still not well understood, and the shaping mechanisms are a subject…
View article: Chemical tracers of a highly eccentric AGB–main-sequence star binary
Chemical tracers of a highly eccentric AGB–main-sequence star binary Open
View article: Evaluating drug stability and sterility in single-dose vials when accessed with a closed system transfer device
Evaluating drug stability and sterility in single-dose vials when accessed with a closed system transfer device Open
Background: Impact of drug wastage is a legitimate and persistent concern. Financial impact of drug waste is borne by the hospital network, patients, and healthcare systems. Measures to reduce drug wastage may have a positive impact throug…
View article: <i>JWST</i> observations of the Ring Nebula (NGC 6720): I. Imaging of the rings, globules, and arcs
<i>JWST</i> observations of the Ring Nebula (NGC 6720): I. Imaging of the rings, globules, and arcs Open
We present JWST images of the well-known planetary nebula NGC 6720 (the Ring Nebula), covering wavelengths from 1.6 to 25 $\, \mu$m. The bright shell is strongly fragmented with some 20 000 dense globules, bright in H2, with a characterist…