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
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
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 Å 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
Martijn van Gelder developed a scaling method to subtract the
contamination from the spectra.
Outreach & Media
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.
69117 Heidelberg, Germany
Office: E 109
E-mail: ramirez (at) mpia.de