Ben's Astrophysics Website
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About

My name is Bernard Lammert de Vries (short Ben). I am currently a researcher at the European Space Agency

My scientific interest lies in the study of planet forming disks, planetesimal evolution, astromineralogy, meteorites and Solar System bodies.

Before working at ESA I worked at the Stockholm Observatory and the Astrobiology Center of Stockholm. Here I collaborated with mineralogists and measured infrared spectra of meteoritic minerals in the laboratory.

I obtained my PhD at the KU Leuven in Belgium with Hans Van Winckel, Joris Blommaert and Rens Waters. During my PhD I could work on brand new observations from the Herschel Space Observatory, which led to multiple nice publications among which a Nature paper on the comets around Beta Pictoris.

I obtained my MSc in Astrophysics cum laude at the University of Amsterdam under the supervision of Rens Waters and Michiel Min. I did my high school in Groningen in the Netherlands.

If you are interested in my full CV or want to get in contact for another reason, please send me an e-mail.

View B.L. de Vries's LinkedIn profile LinkedIn profile

Scientific papers

Here you can find a list of publications about various scientific topics and also my PhD thesis can be downloaded. For the publications for which data and or observations are available, they are also listed. Presentations I have given about selected works can also be viewed.

I try to learn more on astronomical objects by studying minerals in the form of small sand-like particles, formed around stars. This research field is often called astro-mineralogy. Much can be learned from minerals, for example, small sand-like particles are the building blocks of rocky (and possibly gaseous) planets. If you want to know more about this method in astronomy, please have a look at the publications below. I also started a laboratory project, where we measure the optical properties of Earth and Solar System minerals (like in meteorites). If you want to know more on this, follow this link

One of the main topics I am working on is about planets and planetesimals around young stars. Questions I like to adress are about how generic our Solar System is and if there are possibly planetary systems like our own. I am interested in how large rocky bodies grow in disks around young or evolved stars, what those bodies are made of and which mechanisms act on these bodies (e.g. collisions, weathering or heating).

Other topics I like to persue are about the evolution of stars like our Sun or stars that are a few times more heavy. On the one hand I want to know how these stars, and thus our Sun, evolve and what happens if they are almost burned out. On the other hand I am interested to see what kind of disks are formed around these stars at the end of their evolution and see if there are any "surprises" hidden in these disks.

I have also been active as an astronomer at the Mercator Telescope on La Palma and several of my observations have been used for scientific research projects on asteroseismology. Those projects let to the papers which are also listed on this page. My PhD thesis is shown with its summary and a possibility to download the whole book. This page ends with a list of conference proceedings.

The AU Mic Debris Disk: Far-infrared and Submillimeter Resolved Imaging

ApJ, 2015
Matthews, et al.
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Gas and dust in the star-forming region rho Oph A. The dust opacity exponent beta and the gas-to-dust mass ratio g2d

A&A, 2015
Liseau et al.
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The evolved circumbinary disk of AC Herculis: a radiative transfer, interferometric, and mineralogical study

A&A, 2015
Hillen, de Vries, et al.
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Dusty wind of W Hydrae. Multi-wavelength modelling of the present-day and recent mass loss

A&A, 2015
Khouri et al.
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Micron-sized forsterite grains in the pre-planetary nebula of IRAS 17150-3224

A&A, 2015
de Vries, Maaskant, et al.
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Comet-like mineralogy of olivine crystals in an extra-Solar Kuiper belt analogue

Nature, 2012
de Vries, Acke, et al.
Get paper | Data (coming) | Presentation Paris 2014 | Leiden '14

Location and sizes of forsterite grains in protoplanetary disks: interpretation from the Herschel DIGIT programme

A&A, 2014
Maaskant, de Vries, et al.
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Extreme Conditions in a Close Analog to the Young Solar System: Herschel Observations of epsilon Eridani

A&A, 2014
Greaves, ..., de Vries, et al.
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The Debris Disk of Solar Analogue tau-Ceti: Herschel Observations and Dynamical Simulations of the Proposed Multiplanet System
MNRAS, 2014
Lawler, ..., de Vries, et al.
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The problematically short superwind of OH/IR stars

A&A, 2014
de Vries et al.
Get paper | Presentation Vienna '14

Observational evidence for composite grains in an AGB outflow
A&A, 2012
Lombaert, de Vries, et al.
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Herschel/PACS observations of the 69 mu band of crystalline olivine around evolved stars
A&A, 2014
Blommaert, de Vries et al.
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Amorphous carbon in the disk around the post-AGB binary HR 4049

A&A, 2013
Acke, ... de Vries, et al.
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Determining the forsterite abundance of the dust around Asymptotic Giant Branch stars
A&A, 2010
de Vries et al.
Get paper | Vienna '10

H2O vapor excitation in dusty AGB envelopes

A&A, 2013
Lombaert, ..., de Vries et al.
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Detection of a large sample of Gamma Doradus stars from Kepler space photometry and high-resolution ground-based spectroscopy
A&A, 2013
Tkachenko, ..., de Vries et al.
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Detection of gravity modes in the massive binary V380 Cyg from Kepler space-based photometry and high-resolution spectroscopy
MNRAS, 2012
Tkachenko, ..., de Vries, et al.
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Pulsating red giant stars in eccentric binary systems discovered from Kepler space-based photometry

A&A, 2014
Beck, ..., de Vries et al.
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PhD Thesis

Olivine mineralogy of young and evolved stars
PhD Thesis, KU Leuven, Belgium, 2013
B.L. de Vries
Download thesis | Public/Layman thesis presentation

The spectral characteristics of crystalline olivine can be used as a probe of the physical and chemical properties of circumstellar environments. In this thesis are presented the first Herschel Space Telescope observations of the 69 micro-meter band of crystalline olivine in the debris disk of Beta Pictoris and the circumstellar environment of evolved stars.

The observed 69 micro-meter band and other features of crystalline olivine are used to determine the composition and location of the olivine crystals in the young planetary system of Beta Pictoris. This analysis shows that the olivine crystals are part of the collisional debris of relatively small (<10 km) comet-like planetesimals orbiting in a Kuiper belt-like region of the planetary system. It is shown that the composition of the crystals is remarkably similar to those in comets of our Solar System.

A large set of Herschel/PACS observations of the 69 micro-meter band of crystalline olivine in the circumstellar environment of evolved stars is presented. This sample consists out of many different types of evolved stars, among which OH/IR stars, post-AGB stars and planetary nebulae. The 69 micro-meter bands of these stars show that all these different types of evolved sources all produce the same pure magnesium-rich crystalline olivine.

The OH/IR subsection of the large sample of Herschel/PACS observations is analyzed in more detail. It is shown that the current and dense superwind of these objects has started no longer than 1200 years ago and that the dust in their outflows contains 2-14 % crystalline olivine (by mass). Depending on the progenitor mass of the star the short time-scales that are found for the superwind causes a conundrum. The stars with a high mass progenitor star need to go through several of these superwinds in order to lose enough mass to leave the Asymptotic Giant Branch. Until now no such previously emitted superwinds have been detected as extended shells around such objects and the further evolution of these objects is not known