# Jean-Marc Bonnet-Bidaud

Jean-Marc Bonnet-Bidaud (born 1950) is a French astrophysicist at the Atomic Energy and Alternative Energies Commission (CEA). He is a specialist in high-energy astrophysics and in the study of highly condensed stars in the galaxy (white dwarfs, neutron stars and black holes). He is also active in the field of the history of astronomy and in charge of the public outreach for astronomy at CEA.

## Scientific work

Among his highest citation scientific papers are the discovery and collaborative study of an atypical supernova observed in 2006, a scientific review on the enigmatic X-ray source Cygnus X-3 and its reported very high energy emission and the discovery of abnormal CNO abundances among accreting magnetic white dwarfs.
From 2009, Jean-Marc Bonnet-Bidaud is involved in the StarAcc project (initially POLAR project) which aims to reproduce in the laboratory physical conditions similar to those existing on the surface of magnetic white dwarfs thanks to the use of lasers of power. The POLAR project reached an essential milestone in 2016 by demonstrating for the first time the possibility of reproducing in the laboratory an accretion structure (accretion shock and radiative zone) in agreement with numerical predictions and astrophysical observations
This result opens the way to the use of very energetic lasers, such as the NIF (National Ignition Facility-USA) or the LMJ (Laser Megajoule-France), to achieve radiative regimes strictly homothetic to the astrophysical situation. Ultimately, these experiments should make it possible to reliably produce miniature models in the laboratory that are almost analogous to real astrophysical conditions.

## History of science
### History of cosmology

With the philosopher of science Thomas Lepeltier, Jean-Marc Bonnet-Bidaud co-directed the publication in 2012 of the collective work Un autre cosmos ?. The central idea of the book is to encourage researchers to look into alternative cosmological models to that of the Big Bang.
In 2021, Jean-Marc Bonnet-Bidaud and Thomas Lepeltier published the work Big Bang - Histoire critique d'une idée, in which the evolution of the idea of an expanding universe evolving at from a hot phase, at the basis of the current cosmology of the Big Bang is discussed. The authors show how this basic hypothesis evolved in several stages to arrive at the current model known as LCDM (Lamba-Cold-Dark-Matter) in which 95% of the content of the universe remains unknown. A critical analysis is provided of the assumptions underlying this model, highlighting the current difficulties.

### Chinese astronomy

Bonnet-Bidaud is the author of the first scientific study of the oldest known stellar map, the Dunhuang Star Chart, also known as the S.3326 manuscript, a document found in China along the Silk road and now kept at the British Library in London, England. The study concludes to a now revised datation at +650-685, making the chart contemporary of the early Tang dynasty and most probably produced by the famous Chinese astronomer Li Chunfeng.
He has produced in 2017 the book 4000 ans d'astronomie chinoise, that gives an overview of the astronomical discoveries made in China over centuries. The book has been translated in Chinese in 2020 : 书名:4000年中国天文史.