What twirls around this star?

Image credits: Izan Leao (Universidade Federal do Rio Grande do Norte, Brazil).
Image credits: Izan Leao (Universidade Federal do Rio Grande do Norte, Brazil).

A Rotating Spiral Structure Around IRC+10216

Our cosmos is full of star dust, the ashes of stars that died and ejected their matter to the interstellar medium, filling it with dust and gas. When solar like stars consume the hydrogen in their cores, we say that their “main sequence” stage is finished and they begin their final phase. Because IRC+10216 is the high mass-loss star closest to us, it is the best studied evolved star and it seems to keep a secret: it is not alone.

As solar like stars evolve into the Asymptotic Giant Brach (AGB) phase, they eject large amounts of material into the interstellar medium, forming a circumstellar envelope around these objects. Thanks to the Atacama Large Millimeter /submillimeter Array (ALMA) we can now study the innermost regions of the circumstellar envelopes of those evolved stars with unprecedented precision and sensitivity.

IRC +10216 is the best studied evolved carbon-rich star. Located at an estimated distance of 424 light years, this AGB star is the high mass-loss star closest to us. This proximity has allowed the detection of a large number of molecules in its circumstellar envelope. These detections have in turn provided a deep and fruitful study of the chemical processes occurring in the ejected material of this star. The importance of these regions is fundamental since it covers the zone where the dust is formed and accelerated, and the dust grains trigger many chemical reactions.

But, after many studies from different research groups, one question remained unanswered: why was the gas shells irregularly distributed around the central star? In fact, the ejecta around it go from roughly spherical at the large scale, to relatively complex in the innermost regions.

There was a theory to explain the shape of the envelope of this evolved star.

Spiral structure, a companion star?

Understanding the structure of the circumstellar envelope and the molecular gas around this star is fundamental to reveal the chemical processes therein. For example, a clumpy structure may allow the UV radiation coming from the interstellar medium to reach the inner regions of the molecular gas and trigger chemical reactions.

Also the kinematics of these ejecta allows us to study the ejection process from the inner zones and to infer the mechanism involved: the data suggests that the matter released by the ejecta is slowly expanding and rotating.

As gas shells ejected by the evolved star are expected to be spherical, the irregular distribution around it, forming a spiral front, can be explained by the presence of a companion star.

Salts as tracers to confirm the companion star

Astrochemistry uses the data obtained by the different instruments to unveil the role of the different molecules in the chemical processes that take place in the Universe.

For instance, the emission from molecules such as CO and SiS has been found to show the spiral structure of IRC +10216 while that from radicals such as CN or C3H show that the abundance of these molecules is enhanced relatively far from the star. The shape of this distribution fits with the theory of a companion star.

In this work, the metal-bearing molecules were expected to probe the innermost regions of the circumstellar envelope around IRC +10216. The first author, Guillermo Quintana- Lacaci, says “Certain characteristics of the molecules affect to their emission, for instance Sodium Chloride (NaCl) and Potassium Chloride (KCl) provide much better contrast (dynamic range) to see weak structures in regions where other molecules as (Al)-bearing molecules can’t. In particular, NaCl confirms the presence of a face-on spiral extending to the innermost regions of IRC +10216 as well as it shows that this spiral structure is rotating.”

More observations with high angular and spectral resolution would allow the researchers to better constrain the characteristics of the structures detected here, but with this work, the presence of a star orbiting IRC+10216 becomes the explanation that fits the most with the rotating spiral structure seen around it.


More information:

The results of this work were published in the paper “HINTS OF A ROTATING SPIRAL STRUCTURE IN THE INNERMOST REGIONS AROUND IRC+10216”, by G. Quintana-Lacaci (Group of Molecular Astrophysics, ICMM, CSIC, Spain); J. Cernicharo (Group of Molecular Astrophysics, ICMM, CSIC, Spain); M. Agúndez (Group of Molecular Astrophysics, ICMM, CSIC, Spain); L. Velilla Prieto (Group of Molecular Astrophysics, ICMM, CSIC; Centro de Astrobiología, INTA-CSIC, Spain); A. Castro-Carrizo (Institut de Radioastronomie Millimétrique, France); N. Marcelino (INAF, Istituto di Radioastronomia, Italy); C. Cabezas (Grupo de Espectroscopía Molecular (GEM), Unidad asociada CSIC, Universidad de Valladolid (UVA), Spain); I. Peña (GEM, Unidad asociada CSIC, UVA, Spain); J. L. Alonso (GEM, Unidad asociada CSIC, UVA, Spain); J. Zúñiga (Dpto. de Química-Física, Faculdad de Química de la Universidad de Murcia, Spain); A. Requena (Dpto. de Química-Física, Faculdad de Química de la Universidad de Murcia, Spain); A. Bastida (Dpto. de Química-Física, Faculdad de Química de la Universidad de Murcia, Spain); Y. Kalugina (LOMC-UMR 6294, CNRS-Université du Havre, France; Department of Optics and Spectroscopy, Tomsk State University, Russia); F. Lique (LOMC-UMR 6294, CNRS-Université du Havre, France); and M. Guélin (Institut de Radioastronomie Millimétrique; LERMA, Observatoire de Paris, PSL Research University, CNRS, France).

Nanocosmos on the Spanish Newspapers


January and February are being good months for the NANOCOSMOS outreach on the hispanophone Mass Media. Many newspapers published last week an interview with José Cernicharo (one of the three Principal Investigators of the project). You can read one of them, published in “La Opinión, A Coruña”, in this link.

The interview has also been published in other regional newspapers as “La Nueva España”, “Levante (El Mercantil Valenciano)”, “Faro de Vigo”, “La Provincia, diario de Las Palmas” and “La Opinión de Tenerife”.

A summary of the ECLA2016


Last November took place in Madrid the II European Conference on Laboratory Astrophysics, ECLA2016 “Gas on the rocks”. NANOCOSMOS participated as one of the organizers. One of the activities developped was a Press Room, in order to produce communication and outreach materials available during and after the meeting.

You can see several video interviews to invited speakers and other participants in the youtube channel and also read the interviews with some of the experts that attended the meeting.

Youtube playlist of the ECLA2016
Press room of the ECLA2016

ECLA2016 conference ready to go!!

From next Monday 21 till Friday 25, the European Conference on Laboratory Astrophysics (ECLA2016 – Gas on the Rocks) will take place at the CSIC headquarters in Madrid. The opening act will be led by the president of CSIC, Emilio Lora-Tamayo, together with the Director of the Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Federico Soria, and José Cernicharo (SOC chair), Christine Joblin (SOC co-chair) and Isabel Tanarro (LOC chair).

More than 170 scientists worldwide (astrophysicists, physicists, chemists and engineers) will address the state of the art in laboratory astrophysics within the context of new exciting astrophysical data. In order to achieve a closer collaboration in the analysis and interpretation of astrophysical and laboratory data, nearly 80 talks and 90 posters will be presented at the conference.

A dedicated press room will be available at the conference webpage. Several scientists will be interviewed to show the general public how science can improve our current understanding on fundamental questions such as the formation of planetary systems and molecular complexity in Space as well as the interrelation between technological developments and top laboratory studies to address these fundamental questions.

Stay tuned!!

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


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