Related papers: Astrometry of circumstellar masers
The intense line emission of OH masers is a perfect tracer of regions where new stars are born aswell as of evolved stars, shedding large amounts of processed matter into the interstellar medium. From SKA deep surveys at 18 cm, where the…
We conducted radio observations searching for OH 18-cm maser emission from a sample of 169 unclassified MIPSGAL compact Galactic bubbles. These sources are thought to be the circumstellar envelopes of different kinds of evolved stars. Our…
Determination of pulsar parallaxes and proper motions addresses fundamental astrophysical questions. We have recently finished a VLBI astrometry project to determine the proper motions and parallaxes of 27 pulsars, thereby doubling the…
What is long-baseline optical/IR stellar interferometry? A few years ago, many astronomers might not have been able to answer that question properly. This is today hopefully not the case anymore, because mainstream facilities, such as the…
For many decades the determination of accurate fundamental parameters for stars (masses, radii, temperatures, luminosities, etc.) has mostly been the domain of eclipsing binary systems. That has begun to change as long-baseline…
We describe an observing campaign using the Very Long Baseline Array (VLBA) to monitor the time-evolution of the v=1, J=1-0 SiO maser emission towards the Mira variable TX Cam. The data reported here cover the period 1997 May 24 to 1999…
Precise exoplanet characterization requires precise classification of exoplanet host stars. The masses of host stars are commonly estimated by comparing their spectra to those predicted by stellar evolution models. However,…
Physical properties of stars such as luminosity, surface temperature, distance, or mass are measured from observations. These physical properties are of paramount importance to understand how stars are born, live, and die in the universe…
Long-baseline interferometry at optical and near-infrared wavelengths is an emerging technology which is quickly becoming a useful tool to investigate stellar atmospheres and to compare observations with models. Stellar atmosphere models…
I present a brief summary of three different types of binary star - astrometric, spectroscopic and eclipsing - and tabulate the properties of these systems that can be determined directly from observations. Eclipsing binary stars are the…
After decades of efforts, optical long-baseline interferometry has become a mainstream observational technique in terms of operation robustness and user friendliness. Interferometry has opened a new observational window, enabling…
High-mass star formation is not well understood chiefly because examples are deeply embedded, relatively distant, and crowded with sources of emission. Using VLA and VLBA observations of water and SiO maser emission, we have mapped in…
Recent VLBI (Very Long Baseline Interferometer) observations determined the distances and proper motions of star-forming regions in spiral arms directly. They showed that star-forming regions and young stars have large peculiar motions, as…
A long-standing problem in astrophysics is to measure the mass associated with galaxies. Gravitational lensing provides one of the cleanest ways to make this measurement. To date, the most powerful lensing probes of galactic mass have been…
We use the Tremaine-Weinberg method, adapted to the Milky Way, to measure a pattern speed in OH/IR stars located in the inner MW.
Asteroseismology is among the most powerful observational tools to determine fundamental properties of stars. Space-based photometry has recently enabled the systematic detection of oscillations in exoplanet host stars, allowing a…
The supergiant VX Sagittarii is a strong emitter of both H2O and SiO masers. However, previous VLBI observations have been performed separately, which makes it difficult to spatially trace the outward transfer of the material consecutively.…
The HI line at 21 cm is a tracer of circumstellar matter around AGB stars, and especially of the matter located at large distances (0.1-1 pc) from the central stars. It can give unique information on the kinematics and on the physical…
Context: With no conclusive detection to date, the search for exomoons, satellites of planets orbiting other stars, remains a formidable challenge. Detecting these objects, compiling a population-level sample and constraining their…
This chapter discusses the use and possibilities of optical and infrared interferometry to study star formation. The chapter starts with a brief overview of the star formation process and highlights the open questions from an observational…