Fabrice Martins talks with
ScienceWatch.com and answers a few questions about
this month's Emerging Research Front Paper in the field of
Article: A new calibration of stellar parameters of
Galactic O stars
Authors: Martins, F;Schaerer, D;Hillier,
Journal: ASTRON ASTROPHYS, 436 (3): 1049-1065, JUN 2005
Addresses: Max Planck Inst Extraterr Phys, Postfach 1312,
D-85741 Garching, Germany.
Observ Geneva, CH-1290 Sauverny, Switzerland.
Observ Midi Pyrenees, Astrophys Lab, F-31400 Toulouse,
Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260
Why do you think your paper is highly
Our paper provides a calibration of several important parameters of
Galactic O stars—
effective temperature, luminosity, ionizing flux, etc.
These quantities are invaluable to a number of astrophysicists working on
massive stars, star formation, the interstellar medium, or even galactic
structures. The high citation score reflects the fact that our results have
implications well beyond the massive stars research community.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
Our paper describes the effects of a new ingredient in massive stars'
atmospheric models, namely line-blanketing—the decrease in intensity
of a star's spectrum due to many closely spaced, unresolved absorption
"...astronomy in general has always been fascinating
people, and this will continue as long as we,
astrophysists, are able to communicate about the amazing
content of the Universe."
In short, we show that taking properly into account the effects of metals
on the atmospheric structure and emerging spectrum of hot massive stars
deeply affects the relationships between their physical parameters and
Would you summarize the significance of your paper
in layman's terms?
Our paper provides new methods to estimate the properties of hot massive
stars using direct observations. It is thus extremely valuable to anyone
who wants to know what massive star he/she is observing.
How did you become involved in this research and
were any particular problems encountered along the way?
I began my research on the subject of hot massive stars during the period
of my Ph.D. thesis and I'm still working in that field some ten years
later. The main difficulty encountered in this research is to keep
improving the models in order to be able to reproduce better and better
Where do you see your research leading in the
The future of massive stars research will probably be the discovery and
analysis of stars far away from our Galaxy, which will soon be possible
with the advent of a new class of giant telescopes—the so-called
"Extremely Large Telescopes," or "ELTs." We will then be able to observe
stars in very different environments, which will certainly change our
understanding of these fascinating objects.
Do you foresee any social or political
implications for your research?
There are no such implications for the field of massive stars. But
astronomy in general has always been fascinating to people, and this will
continue as long as we astrophysicists are able to communicate our
observations about the amazing content of the Universe.
Fabrice Martins, Ph.D.
CNRS Associate Researcher
Université Montpellier II
KEYWORDS: stars : fundamental parameters; stars : atmospheres; stars :
early-type; BLANKETED MODEL ATMOSPHERES; EFFECTIVE TEMPERATURE SCALE; HOT
LUMINOUS STARS; MASSIVE STARS; FUNDAMENTAL PARAMETERS; MAGELLANIC CLOUDS;
IONIZING FLUXES; SPECTROSCOPIC ANALYSIS; EXPANDING ATMOSPHERES;