IRC+10216 asks for respect for her privacy

In statements made to “The Life of the Stars”, the hottest “celebrities” program of the moment, the IRC+10216 circumstellar envelope has declared to be fed up with being persecuted by the paparazzi.

Distribution of matter around IRC+10216.

It’s been a few years since IRC+10216 rose to fame for going through a rather tumultuous moment in her life. However, in the latter stages, she confesses to being already very fed up with paparazzi’s persecution, who insist (in a way that becomes strenuous) to make known every detail of her daily existence. “I’m especially tired of such an ALMA, it doesn’t leave me alone,” she says angrily. 

Apparently, such “ALMA” has penetrated its intimacies to limits that exceed molecular sizes. Readers of heart magazines and social media users have made multiple comments about it, even with sometimes unwise tweets. “She is dangerously close,” said Luis Velilla (who is causally an astrophysicist and studies stars of this kind) after learning of her statements and her exhausting. Other tweets say “That happens to you for going star” or “as an audience, we don’t like to stay on the surface, we like to go beyond the envelope”.

ALMA, the “paparazzi” of the coldest stars

We have contacted ALMA, the paparazzi of the coldest stars, to find out her opinion. “I was working on cycle zero, which was a bit like my baptism of fire, and I gave to look closely at the celebrity I had closest. Others are dedicated to hot stars. I’m more into evolved, colder stars, who have a lot to tell but who hide their intimacy insistently. It was an impressive challenge for me. It’s not my fault she’s around and she’s a (role) model.”

The last assault on her intimacy perpetrated by ALMA and made public has been the one that has revealed  in detail how silicon is distributed in IRC+10216.

How did this happen?

In the spring of 2012 IRC+10216 was in her things when she realized she was being watched. She had been of interest to the pink press before. But this time it was different. ALMA’s ability to get “to the kitchen” was impressive. As if it were an impressive telephoto lens, ALMA draw with unprecedented precision the map of the distribution SiS, SiO and  SiC2  in the envelope of  this evolved star [1].

For us, who are very gossipy, this has been a real bomb, since knowing the inner parts of IRC+10216 in such detail is very revealing: in particular, the lines of high vibrational levels [2] of SiS come from a very warm region, an area very close to the star with which IRC+10216 maintains a special relationship. This is CW Leonis, who ended up making these statements:

“Yes, IRC+10216 and I have a very close relationship since I reached mature age. This is what happens to evolved stars: we eject the material to the outside in the form of layers. I will not deny it: something special has been born between us. My envelope and I are very close.”

This is not dirty laundry, this is molecules

Penetrating IRC+10216 to the limits with CW Leonis, as if it were the layer of an onion, we stumbled upon SiC2, but this molecule mysteriously disappears as we walk away to, oh surprise, reappear in a thin layer quite far from the star.  This may be due to the capabilities of ALMA [3].

As for SiO, it has a certain extensive and elongated structure. What could this be about? Explaining elongation is very speculative, but it gives rise to interesting ideas.

First, it could be the presence of a dust “belt” in the direction of elongation. This could cause more gas to form due to increased density in that area. Or, maybe, there is a companion star orbiting CW Leonis. This companion star could also create a preferred direction (the plane of the orbit) for material accumulation and increased density, favoring molecular formation. Although it could also be a molecular jet. For now, it’s all assumptions.

For ALMA this has just begun: “I am now finishing cycle two. If in cycle zero I was learning, now I’m taking a wagon: I’ve learned to use my tools and now there’s no one to stop me.”

IRC+10216 has stated that it will continue to grant exclusives as long as the privacy of its relationship with CW Leonis is respected (on the possible companion star she said not much, but it will undoubtedly be another of the hot topics of the “stellar summer”). The most chic community looks forward to news about this relationship that so many articles are generating in the pinker press (scientific, of course).

More information

Paper: “Si-bearing molecules toward IRC+10216: ALMA unveils the molecular envelope of CW Leo” (DOI: 10.1088/2041-8205/805/2/L13).


[1] Detailed maps of the SiS, SiO and SiC2 distribution have been carried out in IRC+10216. In particular, rotational transitions were observed and not only in the fundamental vibrational state, as the detected even SiS rotational transitions of high vibrational levels (v-7) and tentatively (v-10).

[2] Molecules have different energy levels: electronic, vibrational and rotational. Because the energy is quantized, we can know what kind of transition has taken place when a molecular species is excited or deexcited. Within a particular electronic state, the molecule can reach different types of vibrational states (those produced by the vibration of the atoms that make up the molecule) and, in turn, within the same vibrational state, the molecules rotate, producing a rotation spectrum that can be detected with radio telescopes in the domain of millimeter and submillimeter waves.

[3] There is some loss of flow (emission) in the outer thin layer because it has a very large size. This is because in ALMA (and any other interferometer) exists what is called an MRS (Maximum Recoverable Scale), the maximum recoverable scale. This means that any actual structure that is larger than a given formula is filtered and we lose much of its emission.


Image 1: This image shows the central section of a series of images that, as in a scan, allow us to distinguish the distribution of matter around the star IRC+10216. The data for composing this image has been obtained by the IRAM 30m telescope and was developed for the article Molecular shells in IRC+10216: tracing the mass loss history“.

Image 2: ALMA, the “paparazzi” of the coldest stars. Credit:  ESO/B. Tafreshi  (

Originally published in Spanish on the Naukas website:  IRC+10216 pide respeto a su privacidad (2015/07/16).

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