A5016859919- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Molecular Spectroscopy and Structure
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Galaxies: Formation, Evolution, Phenomena
- SAS software applications and methods
- Spectroscopy and Laser Applications
- Cosmology and Gravitation Theories
- Calibration and Measurement Techniques
- Bee Products Chemical Analysis
- High-pressure geophysics and materials
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Phase Equilibria and Thermodynamics
Max Planck Institute for Astronomy
2019-2023
University of Amsterdam
2015-2020
Universidad de Los Andes
2013
We set out to determine stellar labels from low-resolution survey spectra of hot, OBA stars with effective temperature (Teff) higher than 7500K. This fills a gap in the scientific analysis large spectroscopic surveys such as LAMOST, which offers for millions at R=1800. first explore theoretical information content determining labels, via Cram\'er-Rao bound. show that limit perfect model and observed S/N 100, precise estimates are possible wide range labels: not only Teff, surface gravity...
Abstract We present the first results of eXtreme UV Environments (XUE) James Webb Space Telescope (JWST) program, which focuses on characterization planet-forming disks in massive star-forming regions. These regions are likely representative environment most planetary systems formed. Understanding impact planet formation is critical order to gain insights into diversity observed exoplanet populations. XUE targets 15 three areas NGC 6357, hosts numerous OB stars, including some stars our...
Massive stars play a very important role in many astrophysical fields. Yet, some fundamental aspects of their evolution remain poorly constrained. In this regard, there is an open debate on the width main-sequence (MS) phase. We aim to create updated Hertzsprung-Russell (HR) diagram that includes volume-limited and statistically significant sample massive stars. Our goal use investigate extension MS, including information about projected rotational velocities ($v\sin i$) spectroscopic binary...
Massive stars play a very important role in many astrophysical fields. Despite their scarcity with respect to less-massive counterparts, influence on the chemo-dynamical evolution of galaxies is substantial. Yet, some fundamental aspects remain poorly constrained. In this regard, there an open debate width main-sequence (MS) phase, which spend most lifetimes. We aim create updated Hertzsprung-Russell (HR) diagram that includes volume-limited and statistically significant sample massive...
Recent years have seen a surge of interest in the community studying effect ultraviolet radiation environment, predominantly set by OB stars, on protoplanetary disc evolution and planet formation. This is important because significant fraction planetary systems, potentially including our own, formed close proximity to stars. rapidly developing field, with broad range observations across many regions recently obtained or scheduled. In this paper, stimulated series workshops topic, we take...
The formation of massive stars remains poorly understood and little is known about their birth multiplicity properties. Here, we investigate the strikingly low radial-velocity dispersion measured for a sample 11 pre- near-main-sequence (sigma_rv = 5.6 +/- 0.2 km/s) in young star forming region M17 to obtain first constraints on properties stellar objects. Methods: We compute RV synthetic populations various compare simulated sigma_rv distributions observed value. specifically two scenarios:...
The majority of massive stars (> 8 M ⊙ ) in OB associations are found close binary systems. Nonetheless, the formation mechanism these binaries is not understood yet. Using literature data, we measured radial-velocity dispersion ( σ 1D as a proxy for fraction ten Galaxy and Large Magellanic Cloud, spanning an age range from 1 to 6 Myr. We find positive trend this with cluster’s age, which consistent hardening. Assuming universal f bin = 0.7, converted behavior evolution minimum orbital...
The formation process of massive stars is still poorly understood. Massive young stellar objects (mYSOs) are deeply embedded in their parental clouds, they rare and thus typically distant, reddened spectra usually preclude the determination photospheric parameters. M17 one best studied HII regions sky, relatively nearby, hosts a population. With X-shooter on ESO Very Large Telescope we have obtained optical to near-infrared candidate mYSOs, identified by Hanson et al. (1997), few OB this...
Context. Characterising the outcome of star formation process is key to understand and predict evolution stellar populations. Especially fraction massive stars in young clusters importance as they are dominant sources both mechanical radiative feedback, strongly influencing thermal dynamical state their birth environments, beyond. Their supernovae may trigger new generations neighbouring regions. It turns out that a significant escape from parent cluster via interactions single and/or...
Spectroscopic multiplicity surveys of O stars in young clusters and OB associations have revealed that a large portion ($\sim$ 70%) these massive (M$_{i}$ $\gt$ 15 $M_{\odot}$) belong to close short-period binaries (physical separation d $\lt$few au). Despite the recent significant progress, formation mechanisms leading such multiple systems remain be elucidated. As result, (or higher-order systems) are unique laboratories figure out pairing mechanism high-mass stars. We present first...
The interplay between T\,Tauri stars and their circumstellar disks, how this impacts the onset of planet formation has yet to be established. In last years, major progress been made using instrumentation that probes dust structure in mid-plane at surface protoplanetary disks. Observations show a great variety disk shapes substructures are crucial for understanding formation. We studied seemingly old star, PDS\,111, its disk. combined complementary observations stellar atmosphere, hot gas,...
The young massive-star-forming region M17 contains optically visible massive pre-main-sequence stars that are surrounded by circumstellar disks. Such disks expected to disappear when these reach the main sequence. physical and dynamical structure of remnant poorly constrained, especially inner regions where accretion, photo-evaporation, companion formation migration may be ongoing. We aim constrain properties parts stellar objects B243 (6 Msun) B331 (12 Msun), two systems for which central...
The universality and linearity of the Leavitt law are hypotheses commonly adopted in studies galaxy distances using Cepheid variables as standard candles. In order to test these hypotheses, we obtain slopes linear regressions fundamental-mode Cepheids observed by Optical Gravitational Lensing Experiment project Magellanic Clouds. We find that $VI$-bands Wesenheit index behave exponentially, indicating non-linearity. also obtained long-period can be considered universal $VI$-bands, but not index.
Diffuse interstellar bands (DIBs) are broad absorption features measured in sightlines probing the diffuse medium. Although large carbon-bearing molecules have been proposed as carriers producing DIBs, their identity remains unknown. The sight line to young massive star-forming region M17 shows anomalous extinction sense that total-to-selective parameter differs significantly from average Galactic value and may reach values $R_{V} > 4$. Given high $R_V$ values, we investigate whether DIBs...
Context. Recently much progress has been made in probing the embedded stages of massive star formation, pointing to formation scenarios that are reminiscent a scaled-up version low-mass formation. However, latest massive-star have rarely observed, as young stars assumed reveal their photospheres only when they fully formed. Aims. Using first and second overtone CO bandhead emission near- mid-infrared photometry, we aim characterize remnant disks around five unique pre-main-sequence (PMS)...
Context . The outcome of the formation massive stars is an important anchor point in and evolution process these stars. It provides insight into physics assembly process, sets conditions for stellar evolution. For stars, rarely observed because processes involved unfold deep down highly extincted molecular clouds. Aims We characterize a population reddened very young star-forming region M17. group 18 O4.5 to B9 constitutes one best samples almost zero-age main-sequence (ZAMS) high-...
Significant progress has been made toward understanding the formation of massive ($M > 8~$M$_{\odot}$) binaries in close orbits. For example, detection a very low velocity dispersion among stars young region M17 and measurement positive trend with age Galactic clusters. The observed could be explained either by lack this or larger binary separations than typically observed, but fraction similar to other latter implies that over time, components migrate each other. We aim determine origin...
The process of massive star ( M ≥ 8 ⊙ ) formation is still poorly understood. Observations young stellar objects (MYSOs) are challenging due to their rarity, short timescale, large distances, and high circumstellar extinction. Here, we present the results a spectroscopic analysis population MYSOs in Large Magellanic Cloud. We took advantage spectral resolution wavelength coverage X-shooter (300−2500 nm), which mounted on European Southern Observatory Very Telescope, detect characteristic...
51 Oph is a Herbig Ae/Be star that exhibits strong near-infrared CO ro-vibrational emission at 2.3 micron, most likely originating in the innermost regions of circumstellar disc. We aim to obtain physical and geometrical properties system by spatially resolving environment inner gaseous used second-generation VLTI/GRAVITY resolve continuum overtone emission. obtained data over 12 baselines with auxiliary telescopes derive visibilities, differential closure phases as function wavelength....
Context. The identification and characterisation of populations young massive stars in (giant) H II regions provides important constraints on (i) the formation process their early feedback environment, (ii) initial conditions for population synthesis models predicting evolution ensembles stars. Aims. We identify characterise stellar following giant regions: M 8, G333.6−0.2, NGC 6357. Methods. have acquired - K -band spectra around 200 using Multi Object Spectrograph ESO Very Large Telescope....
Context . It is a challenge to study the formation process of massive stars: their time short, there are only few them, they often deeply embedded, and lie at relatively large distances. Our strategy outcome star search for signatures that remain formation. We have access unique sample (massive) pre-main-sequence (PMS) stars in giant H II region M17. These PMS can be placed on tracks Hertzsprung–Russell diagram (HRD) as we detect photospheric spectrum, exhibit spectral features indicative...