-
Lynn Matthews (MIT Haystack Observatory)8/18/25, 1:00 PMInvited talk
The end stages of the lives of cool, low-to-intermediate mass
Go to contribution page
stars ($0.8\le M_{\star}\le 8 M_{\odot}$) are marked by the onset of a range of
complex and dynamic atmospheric phenomena, including radial
pulsations, large-scale convection, and the onset of
intense mass loss through dense, low-velocity winds. These winds
expel up to 80% of the star's initial mass back into the
interstellar... -
Ka Tat Wong8/18/25, 1:40 PMContributed talk
HCN is one of the most abundant molecules in the circumstellar envelopes of carbon-rich AGB stars. Recent single-dish observations have revealed the widespread presence of its emission lines in vibrationally excited states. These include two intense sub-millimetre laser lines at 805 and 891 GHz that originate from a system of two Coriolis-coupled vibrationally excited states at an excitation...
Go to contribution page -
Tomasz Kaminski (CAMK Toruń)8/18/25, 2:00 PMContributed talk
I am going to review the last two decades of studies of objects undergoing a stellar collision or recovering from a coalescence. Among them are transients known as red novae. These objects produce dusty circumstellar remnants rich in molecules. I am going to present observations of these remnants that are helping us to decode the merger process, its causes, and final products.
Go to contribution page -
Sergio Abraham Dzib Quijano (Max Planck Institute for Radio Astronomy)8/18/25, 2:20 PMContributed talk
High-angular-resolution radio observations offer a unique opportunity to identify young stars inside ultracompact HII regions and study their dynamic interactions in early phases of star formation. In this work, I will present recent results from Karl G. Jansky VLA observations targeting two different environments. In NGC 6334A, we conducted a multi-epoch, multi-frequency study of the...
Go to contribution page -
Nimesh Patel (Center for Astrophysics | Harvard & Smithsonian)8/18/25, 2:40 PMContributed talk
We conducted spectral-line surveys of surveys of five evolved
Go to contribution page
stars---IRC+10216, CRL 618, CRL 2688, VY Canis Majoris (VY CMa),
and NGC 7027--- using Submillimeter Array (SMA). These studies aimed
to elucidate the chemical and morphological transformations that
occur: (i) in the transition from the asymptotic giant branch (AGB)
phase to planetary nebulae (PN); and (ii) in oxygen-rich... -
Keiichi Ohnaka (Universidad Andres Bello)8/18/25, 3:20 PMContributed talk
The mass-loss mechanism in asymptotic giant branch (AGB) stars is not yet fully understood. It is of paramount importance to spatially resolve the region within several stellar radii, where the stellar wind accelerates. We present high-angular-resolution ALMA imaging of the well-studied AGB star W Hya, combined with contemporaneous visible polarimetric imaging with VLT/SPHERE-ZIMPOL and...
Go to contribution page -
Cormac Larkin (MPI Kernphysik & ZAH/ARI)8/18/25, 3:40 PMContributed talk
Recent JWST observations towards Westerlund 1 have revealed extensive nebular emission associated with the cluster. Given the age of the region and proximity of that material to massive stars it cannot be primordial star forming gas and the origin is uncertain. One explanation for the nebulosity is ablation flows from Red Supergiant (RSG) stars embedded in the cluster wind driven by the...
Go to contribution page -
Helmut Wiesemeyer (Max-Planck-Institut für Radioastronomie)8/18/25, 4:00 PMContributed talk
Evolved stars, as cosmic carbon and dust factories or progenitors of supernovae, play an essential role in the cosmic cycle of matter, yet they are far from being fully understood. This contribution will give two examples.
The photochemistry of their envelopes is thought to be almost exclusively driven by the interstellar radiation field (ISRF). While the line-profile modeling of emissions...
Go to contribution page -
Javier Alcolea (Observatorio Astronómico Nacional (IGN/CNIG, Spain))8/18/25, 4:20 PMContributed talk
The transformation of the circumstellar envelopes of asymptotic giant branch stars (AGB-CSEs) into first pre-planetary nebulae (pPNe) and later on planetary nebulae (PNe) is one of the most intriguing problems in modern Astrophysics. After more than 30 years of research, the community is convinced that the large variety of bizarre geometries of pPNe and PNe can only be explained by the...
Go to contribution page -
Lars Nyman (Chalmers University of Technology)8/18/25, 4:40 PMContributed talk
HR3126 is a bright M-star surrounded by an extensive E-W bipolar (10' x 3') outflow seen in optical/infrared/CO-emission. VLTI observations show the central star and the presence of a central disk with a size of about 5 mas. We will present the results of ALMA observations of the outflow in the CO (1-0) line over a region of 5' x 5' at a resolution of 2.5". The CO emission traces the inner 3'...
Go to contribution page -
Anton Zensus8/18/25, 5:30 PMContributed talk
-
Poster
Using the APEX telescope, we have observed a sample of 90 evolved stars in the CO(2-1), (3-2), (4-3), and (6-5) transitions. The sample is CO-intensity limited
Go to contribution page
and has been selected from the APEX line pointing source catalog. The targets comprise several carbon stars, M-stars, S-stars, supergiants, and planetary nebulae.
Since these sources are used for regular pointing measurements, we... -
Poster
AGB stars are potential contributors to the overall lifecycle of dust and gas in the Universe. To quantify that contribution as well as possible accurate dust and gas mass-loss rates are needed.
Go to contribution page
The expansion velocity of the stellar wind enters linearly in such a calculation. It can be measured though e.g. (OH) maser emission of thermal CO emission.
In 2016 we presented the first detection... -
Ka Tat WongContributed talk
-
Wenjin Yang (Nanjing University)Contributed talk
Using SOFIA/4GREAT observations and Herschel/HIFI archival data, we analyzed six HCN transitions in the Coriolis-coupled system between the (1,1$^{1e}$,0) and (0,4$^0$,0) vibrational states toward eight carbon-rich AGB stars. We discovered three new HCN laser transitions at 964, 968, and 1055 GHz in seven, six and five stars. The previously known lasers at 805 and 891 GHz also were detected in...
Go to contribution page -
Nimesh Patel (Center for Astrophysics | Harvard & Smithsonian)Contributed talk
-
Lynn Matthews (MIT Haystack Observatory)Invited talk
Choose timezone
Your profile timezone: