Carbon grains around evolved stars

The Nanocosmos team published in October 21, 2019, at Nature Astronomy (available free at Europe PubMed Central), the results of a set of laboratory experiments showing that gas-phase chemistry, under conditions similar to those of a red giant star environment, can produce very efficiently small amorphous carbon grains and carbon chains similar to those found in oil.

Stardust, an ultra-high vacuum machine built in the ERC Nanocosmos project (a Synergy project funded by the European Research Council), was specifically conceived to simulate, with a high level of control, the complex conditions of stardust formation and processing in the environment of evolved stars. In addition, the AROMA setup was built to analyse the molecular content of the samples synthesized by Stardust.

In the words of José Ángel Martín-Gago (Institute of Materials Science of Madrid, ICMM-CSIC, Spain), responsible for the Stardust instrument, “Mimicking the conditions of the envelope of an evolved star, laboratory experiments allow scientists to follow, step by step, the formation process of dust grains, from atoms to simple molecules and their growth to more complex clusters of molecules.”

For José Cernicharo (Institute of Fundamental Physics, IFF-CSIC, Spain), lead co-investigator of the project together with Martín-Gago and Christine Joblin (Institut de Recherche en Astrophysique et Planétologie, IRAP-CNRS, France), “That process is important because those grains of dust, which emerge from the final stages of the evolution of medium-sized stars like our Sun will provide the fundamental pieces needed for the birth of the planets and the main ingredients for the onset of life once injected into the interstellar medium.”

This is why it is essential to develop experiments combining laboratory astrophysics, surface science and astronomical observations to unveil the chemical routes that operate in the inner layers of the envelope of evolved stars.

The results obtained show the formation of amorphous carbon nanograins and aliphatic carbon clusters with traces of aromatic species and no fullerenes. This shows that the latter species cannot form effectively by gas-phase condensation at these temperatures in the zone of the evolved star where the dust is formed, a region that extends up to a few stellar radii.

Chemical complexity

Carbon dust analogues were produced in Stardust and analysed with several characterization techniques including Scanning Tunneling Microscopy and mass spectrometry with the AROMA setup. To produce them only gas carbon atoms and molecular hydrogen were used in a ratio close to that in the atmospheres of AGB stars.

The results showed two types of products: amorphous carbonaceous nanograins – the most abundant, considered to be the main component of carbonaceous star dust – and aliphatic carbon groups. But almost no aromatic molecules were found in the analysis.

According to Joblin, “Polycyclic aromatic hydrocarbons (PAHs) are widespread in massive star-forming regions and in carbon-rich protoplanetary and planetary nebulae. Large carbonaceous molecules like buckminsterfullerene C60 have also been detected in some of these environments. But it seems that they need different conditions to be formed”.

One possible pathway could be through thermal processing of aliphatic material on the surface of dust, which could take place as a result of the significant rise in the temperature of nanograins that occurs in highly UV-irradiated environments. Those results give us new insights into the chemistry of carbonaceous stardust seed formation and foster new observations in order to constrain the physical and chemical conditions in the inner shells of the envelops of evolved stars.

About the ERC

The European Research Council, set up by the European Union in 2007, is the premier European funding organisation for excellent frontier research. Every year it selects and funds the very best, creative researchers of any nationality and age to run projects based in Europe. The ERC has three grant schemes for individual principal investigators – Starting Grants, Consolidator Grants, and Advanced Grants – and Synergy Grants for small groups of excellent researchers.

To date, the ERC has funded more than 9,000 top researchers at various stages of their careers, and over 50,000 postdoctoral fellows, PhD students and other staff working in their research teams. The ERC strives to attract top researchers from anywhere in the world to come to Europe.

The ERC is led by an independent governing body, the Scientific Council. The ERC current President is Professor Jean-Pierre Bourguignon. The ERC has an annual budget of €2 billion for the year 2019. The overall ERC budget from 2014 to 2020 is more than €13 billion, as part of the Horizon 2020 programme, for which European Commissioner for Research, Innovation and Science Carlos Moedas is currently responsible.

Elegant and fast: the GACELA is running

The Gas Cell chamber

On June 7, 2019, a first paper on the GACELA (GAs CEll for Laboratory Astrophysics) experimental set-up is out at the “Astronomy & Astrophysics” journal (A&A, volume 626, A34, 2019).

More than 3 years have elapsed since the first designs were envisaged for this set-up. Finally, at the end of 2017, the chamber (see figure above) was delivered and successfully tested against leaks. On the other hand, the GACELA broad-band radio receivers (Q and W bands, 31.5–50 and 72–116.5 GHz, respectively) were successfully commissioned in the second semester of 2017 and interfaced with the GACELA set-up in February 2018. Several experimental runs were performed, showing high quality signal-to-noise ratio spectra of molecular species (CH3CN, CH3OH, CH4/N2, CH4/N2/CH3CN, etc).

As stated by the authors, GACELA has achieved an important milestone. It is the first time that we can observe the thermal emission of molecules with an instantaneous band width of 20 GHz in Q band and 3 × 20 GHz in W band for Laboratory Astrophysics. These rotational spectroscopy measurements are complemented by mass spectrometry and optical spectroscopy.

In summary, NANOCOSMOS has developed an elegant and fast-responding set-up, the GACELA, to provide high-resolution and high-sensitivity spectra of molecular species produced in cold plasmas or UV experiments.

More information:

This research was presented in the paper “Broad-band high-resolution rotational spectroscopy for laboratory astrophysics“, published in Astronomy and Astrophysics 626, A34 (29pp), 2019 June 7. The authors are: José Cernicharo (Instituto de Física Fundamental, IFF-CSIC), Juan D. Gallego (Centro de Desarrollos Tecnológicos, Observatorio de Yebes, IGN), José A. López-Pérez (CDT, OY, IGN), Félix Tercero (CDT, OY, IGN), Isabel Tanarro (Instituto de Estructura de la Materia, IEM-CSIC), Francisco Beltrán (CDT, OY, IGN), Pablo de Vicente (CDT, OY, IGN), Koen Lauwaet (Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC & IMDEA Nanociencia), Belén Alemán (ICMM-CSIC & IMDEA Materiales), Elena Moreno (IFF-CSIC), Víctor J. Herrero (IEM-CSIC), José L. Doménech (IEM-CSIC), Sandra I. Ramírez (Centro de Investigaciones Químicas, UAEM, Mexico), Celina Bermúdez (IFF-CSIC), Ramón J. Peláez (IEM-CSIC), María Patino-Esteban (CDT, OY, IGN), Isaac López-Fernández (CDT, OY, IGN), Sonia García-Álvaro (CDT, OY, IGN), Pablo García-Carreño (CDT, OY, IGN), Carlos Cabezas (IFF-CSIC), Inmaculada Malo (CDT, OY, IGN), Ricardo Amils (CDT, OY, IGN), Jesús Sobrado (Centro de Astrobiología, INTA-CSIC), Carmen Díez-González (CDT, OY, IGN), José M. Hernández (IFF-CSIC/CDT, OY, IGN), Belén Tercero (CDT, OY, IGN), Gonzalo Santoro (ICMM-CSIC), Lidia Martínez (ICMM-CSIC), Marcelo Castellanos (IFF-CSIC), Beatriz Vaquero-Jiménez (CDT, OY, IGN), Juan R. Pardo (IFF-CSIC), Laura Barbas (CDT, OY, IGN), José A. López-Fernández (CDT, OY, IGN), Beatriz Aja (Universidad de Cantabria), Arnulf Leuther (Fraunhofer Institut fur Angewandte Festkorperphysik, Germany), José A. Martín-Gago (ICMM-CSIC).

The GACELA experimental set-up is located at the Centro de Desarrollos Tecnológicos, Observatorio de Yebes, thanks to a bilateral agreement between CSIC and IGN for the development of the NANOCOSMOS project.

Astrochemistry Insights in Science Magazine, by Christine Joblin and José Cernicharo

Cone Nebula (NGC 2264) Credits: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA.

Detecting the building blocks of aromatics” is the title of this “Insight” written by Christine Joblin and José Cernicharo (both NANOCOSMOS PIs together with J.A. Martín Gago) and talking about the history and importance of the work published by Brett A. McGuire et al. (“Detection of the aromatic molecule benzonitrile (c-C6H5CN) in the interstellar medium“) in the “Science Magazine” (12/01/2018).

This is the summary of the article from C. Joblin and J. Cernicharo:

“Interstellar clouds are sites of active organic chemistry. Many small, gasphase molecules are found in the dark parts of the clouds that are protected from ultraviolet (UV) photons, but these molecules photodissociate in the external layers of the cloud that are exposed to stellar radiation (see the photo). These irradiated regions are populated by large polycyclic aromatic hydrocarbons (PAHs) with characteristic infrared (IR) emission features. These large aromatics are expected to form from benzene (C6H6), which is, however, difficult to detect because it does not have a permanent dipole moment and can only be detected via its IR absorption transitions against a strong background source (2). On page 202 of this issue, McGuire et al. (3) report the detection of benzonitrile (c-C6H5CN) with radio telescopes. Benzonitrile likely forms in the reaction of CN with benzene; from its observation, it is therefore possible to estimate the abundance of benzene itself”.

 

NANOCOSMOS at the Guillermo Haro School on Molecular Astrophysics (Puebla, Mexico)

Prof. José Cernicharo has been awarded with the Guillermo Haro Visiting Professorship 2016 at the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE, posterGH16Puebla, Mexico). Following this award, INAOE has organized the Guillermo Haro School on Molecular Astrophysics (October 11 – 21, 2016). Several NANOCOSMOS scientists (Asunción Fuente from CNIG-IGN, Nuria Marcelino, José Pablo Fonfría and Luis Velilla from ICMM-CSIC) will give lectures on the following topics:

  • Molecular Astrophysics, Spectroscopy, Chemistry in the ISM (José Cernicharo)
  • Physical and chemical processes in the ISM, Protoplanetary disks (Asunción Fuente)
  • Observational methods and interpretation (Nuria Marcelino)
  • Molecular excitation and radiative transfer, Circumstellar medium (José Pablo Fonfría)
  • Chemistry in the circumstellar medium, atmospheric  effects and calibration (Luis Velilla)

José Cernicharo will give a public talk in Puebla downtown on Thursday 13: “Moléculas en el espacio: Astroquímica”.

NANOCOSMOS on top: Press releases from Nature´s “Compression and ablation of the photo-irradiated molecular cloud the Orion Bar”

The paper “Compression and ablation of the photo-irradiated molecular cloud the Orion Bar” (Goicoechea et al. 2016) recently published in Nature, has put Astrochemistry and NANOCOSMOS in the leading edge forefront of many research institutIons, newspapers and mass media. A few examples can be found below:

ESO Picture of the week

CSIC

L´Observatoire de Paris

Institut de Radioastronomie Millimétrique (IRAM)

Institut de Recherche en Astrophysique et Planétologie (IRAP)

ALMA news

El Mundo newspaper

ABC newspaper

La Vanguardia newspaper

El diario newspaper

 

ECLA 2016 – webpage open

Ecla2016-1125x510

The second announcement of the European Conference on Laboratory Astrophysics – “Gas on the Rocks” – ECLA 2016 has been issued today.  This conference will be held at the CSIC headquarters (Madrid, Spain) in November 21 – 25, 2016. The webpage is open with all the relevant information.

www.ecla2016.com

More than 30 invited researchers will address new insights on the following science topics:

  • Comets, asteroids, meteorites and the primitive Solar System nebula: formation and evolution
  • Protoplanetary disks and planet formation
  • Planet, Moon, and exoplanet surfaces and atmospheres
  • The signatures of the evolving interstellar medium
  • Dense Clouds: the gas-ice interface and molecular complexity
  • Chemical fingerprints of star formation
  • The late stages of star evolution: dust formation
  • Supernovae and shocks: high-energy processing of matter

NANOCOSMOS will organize the ECLA2016 – Gas on the Rocks conference

Stardustiram_PdV

The European Conference on Laboratory Astrophysics – Gas on the Rocks (ECLA2016) will be held at the CSIC headquarters in Madrid on November 21 – 25, 2016.

The conference will address the state of the art in laboratory astrophysics within the context of new astrophysical data and to improve communication and collaboration between astrophysicists, physicists and (geo) chemists. Hence, the conference structure will consist of invited talks presenting topics in astrophysics and planetary science and related laboratory astrophysics activities. Contributing talks will be selected to complement the topics from the astrophysical, laboratory, and theoretical/modeling points of view.

More info here

 

NANOCOSMOS at the recent ALMA / Herschel Archival Workshop (Garching, Germany)

alma_herschel_low_resFour NANOCOSMOS researchers gave their presentations at the ALMA/Herschel Archival Workshop held in Garching (Germany) at the ESO headquarters in April 15 -17, 2015. José Cernicharo (NANOCOSMOS Corresponding P.I.) talked about the synergies between the ALMA high resolution observations in the innermost zones of star-forming regions, AGB, post-AGBs stars and extragalactic objects and those of Herschel´s archive submillimeter and far-IR observations. Our postdoctoral researchers, Marcelino Agúndez, Guillermo Quintana-Lacaci and Belén Tercero talked about the following topics: Continue reading →

5-6 May, 2015 – NANOCOSMOS Kick-Off Meeting!

The NANOCOSMOS Kick-Off meeting will be held at the CSIC headquarters (C/ Serrano 113-123, Madrid) in May 5 and 6, 2015. NANOCOSMOS will gather all the major players of the project together. It is expected that synergy will evolve among the NANOCOSMOS partners and foster in-depth discussions in order to set an overall framework for the prospective research and technical tasks. More info here