I am a postdoctoral fellow at the PSF department of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany. I obtained my PhD at the Anton Pannekoek Institute (API), University of Amsterdam in the Netherlands (you can access my PhD thesis here ). My current research interests include the formation and early evolution of massive stars, the properties of remnant disks around massive young stellar objects, and the insterstellar environment in high mass star forming regions. A PDF with my CV can be found here.


Massive stars play a crucial role in the Universe. They shape their surroundings by injecting large amounts of energy and momentum and they produce new, heavy elements that are the building blocks of new stars, planets, and life. They are usually observed in close binaries. Due to the lack of observations covering the earliest stages of their lives, the formation process of massive (binary) stars is poorly understood. In order to learn about the formation and early evolution of massive stars I do observational studies of the outcome of massive star formation. You can view my publications in ADS here. My ORCID iD is 0000-0001-9698-4080

Formation of massive close binaries

Here we present the first empirical evidence in favour of migration as a scenario for the formation of massive close binary stars. We find a positive correlation of the radial-velocity dispersion of young OB associations with their age. This is consistent with massive close binaries forming in wide orbits that harden in the first few Myrs of evolution. You can see the press release here (image credit: MPIA graphics department).

The young stellar content of three giant HII regions

Here we present a photometric and spectroscopic study of massive stars in three HII regions (M8, NGC6357 and G333.6-0.2) and characterised their stellar populations in terms of age and mass ranges.

Are massive close binaries born in wide orbits?

In this paper we explore the dearth of short-period binaries in the massive star forming region M17. We propose that massive binaries are initially formed at larger separations, then harden or migrate to produce the typical power-law period distribution observed in few Myr-old OB binaries. You can see the press release in Dutch here, and here is a note in English.

Massive pre-main-sequence stars in M17

Here we present the first spectroscopically confirmed sample of massive pre-main sequence (PMS) stars in the giant HII region M17. The PMS stars have radii that are consistent with being contracting towards the main sequence and are surrounded by a remnant accretion disk.

Diffuse interstellar bands in M17

In this paper we measure the properties of the most prominent DIBs in M17 and study these as a function of E(B − V) and RV. We find trends between the strength of the studied DIBs (per unit visual extinction) and RV−1, most notably for the 6196 and 7224 DIBs.

Massive young stellar objects in 30 Doradus

We present the results on an X-shooter spectroscopic analysis of the top ten Spitzer MYSO candidates in 30 Dor. As the spectra of the mYSO candidates are contaminated by nebular emission, in this paper Martijn van Gelder developed a scaling method to subtract the contamination from the spectra.

Outreach & Media

Fuerza Latina
Fuerza Latina is a project from the Deutsche Welle that aims to exalt the work of Latin American women in several areas. I was invited to participate in a conversation other Latin American astronomers and space scientists about what it is like to be an astronomer. ( Watch video ).

Shots de Ciencia
I was invited to participate in the podcast Shots de ciencia to talk about massive stars and their importance in the Universe. ( Listen to the podcast ).

Hablemos del Universo
Together with my friend and colleague Camilo Peñaloza from the University of St. Andrews we talked about the origin and evolution of stars at Hablemos del Universo (let's talk about the Universe), a space created by the Planetarium of Bogotá, Colombia. This is the press note from the Instituto Distrital de las Artes (IDARTES) about the event ( Watch video ).

Clubes de Ciencia Colombia
In July 2019 I had the opportunity to participate as an instructor in Clubes de Ciencia in Bucaramanga, Colombia. Together with my friend and colleague Juliana Sandoval we designed a one-week workshop called El supermercado Galáctico (the Galactic supermarket), where we developed several activities to familiarize high school students with the concepts spectroscopy and stellar classification.

Beta in the City
Together with my PhD supervisor, Lex Kaper. We gave a public talk called "Are stars born with a companion or single?" as part of the event Beta in de Binnenstad, a discussion platform organized by SPUI25 in the city center of Amsterdam, where scientist from different disciplines talk to students and the public about their research topics.


Königstuhl 17
69117 Heidelberg, Germany
Office: E 109
E-mail: ramirez (at) mpia.de