TOMER SHENAR

stellar astrophysicist

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My name is Tomer Shenar, born in 1986 in Israel. My research focuses on massive stars. Today, we know that the vast majority of massive stars interact with companion stars during their lifetime: My research is dedicated to study this interaction and its implication on stellar evolution. 

I collect and use multi-wavelength spectroscopic, photometric, and interferometric data with the world's largest telescopes to infer the  observational properties of massive stars and binaries in the Local Group. I develop and utilise state-of-the-art model atmospheres and spectral disentangling algorithms to derive robust constraints on the progenitors of compact objects (Wolf-Rayet stars, OB-type stars, stripped stars), with the goal of advancing our understanding of the evolution of massive stars and binaries and the production of gravitational-wave sources. I am a co-developer of the Potsdam Wolf-Rayet (PoWR) code.

I obtained by B. Sc. degree in July 2010 in Mathematics and Physics in the Technion, Haifa, Israel. I later perused my Master's and PhD degrees in astrophysics in the university of Potdsdam, Germany, under the supervision of Wolf-Rainer Hamann. I'm currently a postdoctoral researcher at the Katholieke Universiteit Leuven (KU Leuven), Belgium. 

As of Oct. 2021, I will be working as a Marie Skłodowska-Curie fellow at the University of Amsterdam, Netherlands. 

 

 
 

Skills

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  • Observations with world's largest observatories: ((e.g., Hubble STIS, COS;  ESO UVES,X-SHOOTER,GRAVITY)

  • Spectral disentangling (Fourier & wavelength space) of binaries and multiple systems

  • Quantitative spectroscopy of Galactic and extragalactic Wolf-Rayet, Be, OB-type, and binary-stripped stars and binaries

  • Wind analysis: mass-loss, clumping, wind-wind collisions

  • Orbital analyses

  • Development of model atmosphere codes; radiative transfer in expanding atmospheres (PoWR code)

  • Interpretation of multi-wavelength spectra from X-ray to infrared

  • Statistical comparisons with evolution models (MESA, BPASS, Bonn)

  • Teaching and supervising of BSc, MSc, and PhD students

  • FORTRAN // C // Python // IDL // LINUX // LaTeX // Mathematica

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Quadruple analysis AB 6
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empirical mass-luminosity relation
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geometry of rotating winds
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disentanglement of R 145
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magnetospheres (HD 54879)
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orbital solution for R 145
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Research interests

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  • The evolution of massive single and binary stars across cosmic times.

  • Formation of gravitational-wave progenitors from binaries at different metallicities

  • Properties of the first stars

  • Formation of Wolf-Rayet stars (as single stars and binaries) at different metallicities

  • Evolution of the most massive stars; the upper-mass limit

  • Origin of Be stars 

  • Occurrence of binary-stripped stars

  • Stellar feedback

  • Magnetism in massive stars

  • Origin of X-rays in massive stars;

  • X-ray binaries

  • Detection of black holes in stellar binaries

WHY ASTROPHYSICS?

My fascination for the universe has never left me ever since taking part in an astronomical event in the Negev, a desert in the southern region of Israel, at the age of 14. I learned that all these thousands of bright points in the night sky were suns, much like our own, but in different shapes and sizes. That day I realized that my connection with the stars would accompany me for the rest of my life. 

Through my work, I hope to advance our understanding of stars, and inspire young, curious pupils and students to investigate the Universe we live in.

 
The Stars

Fellowships & third-party funding

  • Jun. 2021: 3-year senior FWO fellowship (PI)

  • Feb. 2021: 2-yr Marie Skłodowska-Curie Individual fellowship (PI)

  • Feb 2019: funding by the ChETEC COST action (PI)

  • Aug. 2019: 4-yr FWO PhD fellowship (scientific PI and co-supervisor)

  • Sep. 2018: ERC-funded position (formal PI: Prof. Hugues Sana)

  • Oct. 2016: DLR-funded 

  • Jan. 2013: Richard-Winter scholarship for excellency 

 

Prizes & awards: 

  • Jun. 2021: KU Leuven's Research Council Award 

  • Mar. 2018; Horizon 2020 Seal of excellence

  • Oct. 2017: Carl-Ramsauer award, Berlin Physics society

  • Jan. 2017: graduated summa cum laude

  • Sep. 2016: visit at the MIT, funded by the Chandra visitor program

  • Jul 2014: Physics thesis award, Berlin physical society

  • Jul. 2013: Award for outstanding achievements of international students, DAAD

  • 3-year senior FWO fellowship (PI)

  • 4-yr FWO PhD fellowship (scientific PI and co-supervisor

 

 

PUBLICATIONS

85 publications (55 refereed; 20 first-author, h-index 20)

 
 
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Some students I (co-)supervise

PhD: Karan Dsilva

KU Leuven

Karan takes a modern look at the Galactic Wolf-Rayet stars and tries to understand how they evolved.

 

Check out his recent publication, where he finds a lack of short-period WC binaries:

Dsilva, Shenar et al. 2020, A&A, 641, 26

Stay tuned for results about the WN population... (Dsilva et al. in prep.)

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PhD: Julila Bodensteiner

KU Leuven

Julia searches for post-interaction binaries in clusters.

 

Julia finds a clear excess of Be stars in evolved clusters. Together with Julia, we also found some very cool Be stars (confused as black holes) hiding not far away from us!

Bodensteiner, Shenar+ 2020a

Bodensteiner, Shenar+ 2020b

Shenar, Bodensteiner+ 2020

 

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MSc + PhD: Soetkin Jannsens

KU Leuven 

Soetkin analysed a highly complex Wolf-Rayet "binary" in the Large Magellanic Cloud.  "Binary", because she found it's a quadruple or quintuple system, hosting one of the most massive contact systems known

Jannsens, Shenar et al. 2020, A&A, 646, 33

Soetkin now continues her PhD under my co-supervision with the goal of hunting for black holes with Gaia. Stay tuned!

 

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MSc: Roel Lefever
KU Leuven

The majority of Wolf-Rayet analyses assume a fixed wind velocity law. Roel performed a quantitative investigation of alternative velocity laws and their impact on the spectral appearance of Wolf-Rayet stars and their inferred stellar parameters, with important implications on the properties of black-hole progenitors.

Check out his upcoming publication (Lefever, Shenar et al. in prep.)

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MSc: Sancho Luijten

University of Amstedam

Sancho will be analysing multi-epoch data acquired with the UVES@ESO spectrograph (PI: Shenar), targeting two very unique WR binaries. These binaries were proposed to host not one, but two Wolf-Rayet stars, and hence potentially correspond to a rare evolutionary phase prior to black-hole + black-hole binary formation. 

Stay tuned!

 

PUBLIC OUTREACH

  • Activities in kindergartens:  Introduction to our solar system 

  • Mentoring of pupils in astronomy-related projects, at the   University of Potsdam, Germany

  • Physics & Maths tutoring of pupils with socially or economically disadvantaged background (Elele center, Berlin)

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Solar system

Introducing the children to the solar system

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Self expression

The children draw their own impression of the solar system

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Model

The kids "pretended" to be planets revolving around the sun - lots of fun!

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The real thing
The real thing

The kids were inspired by real pictures and simulations of planets, stars, and galaxies

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PRIVATE

When I'm not doing science, I read, play the guitar & piano, and I love to sing. I play adventure games, dance, or just hang out with my dear ones. More about me over a beer (or two)!