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Large granulation cells on the surface of the giant star π1 Gruis

Overview of attention for article published in Nature, December 2017
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About this Attention Score

  • In the top 5% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (99th percentile)
  • Good Attention Score compared to outputs of the same age and source (73rd percentile)

Mentioned by

19 news outlets
11 blogs
10 tweeters
2 Facebook pages
2 Wikipedia pages
2 Google+ users


7 Dimensions

Readers on

8 Mendeley
Large granulation cells on the surface of the giant star π1 Gruis
Published in
Nature, December 2017
DOI 10.1038/nature25001
Pubmed ID

C. Paladini, F. Baron, A. Jorissen, J.-B. Le Bouquin, B. Freytag, S. Van Eck, M. Wittkowski, J. Hron, A. Chiavassa, J.-P. Berger, C. Siopis, A. Mayer, G. Sadowski, K. Kravchenko, S. Shetye, F. Kerschbaum, J. Kluska, S. Ramstedt


Convection plays a major part in many astrophysical processes, including energy transport, pulsation, dynamos and winds on evolved stars, in dust clouds and on brown dwarfs. Most of our knowledge about stellar convection has come from studying the Sun: about two million convective cells with typical sizes of around 2,000 kilometres across are present on the surface of the Sun-a phenomenon known as granulation. But on the surfaces of giant and supergiant stars there should be only a few large (several tens of thousands of times larger than those on the Sun) convective cells, owing to low surface gravity. Deriving the characteristic properties of convection (such as granule size and contrast) for the most evolved giant and supergiant stars is challenging because their photospheres are obscured by dust, which partially masks the convective patterns. These properties can be inferred from geometric model fitting, but this indirect method does not provide information about the physical origin of the convective cells. Here we report interferometric images of the surface of the evolved giant star π1 Gruis, of spectral type S5,7. Our images show a nearly circular, dust-free atmosphere, which is very compact and only weakly affected by molecular opacity. We find that the stellar surface has a complex convective pattern with an average intensity contrast of 12 per cent, which increases towards shorter wavelengths. We derive a characteristic horizontal granule size of about 1.2 × 1011 metres, which corresponds to 27 per cent of the diameter of the star. Our measurements fall along the scaling relations between granule size, effective temperature and surface gravity that are predicted by simulations of stellar surface convection.

Twitter Demographics

The data shown below were collected from the profiles of 10 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 8 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Unknown 8 100%

Demographic breakdown

Readers by professional status Count As %
Researcher 2 25%
Student > Ph. D. Student 2 25%
Student > Master 1 13%
Professor 1 13%
Student > Postgraduate 1 13%
Other 1 13%
Readers by discipline Count As %
Physics and Astronomy 6 75%
Immunology and Microbiology 1 13%
Unspecified 1 13%

Attention Score in Context

This research output has an Altmetric Attention Score of 217. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 08 January 2019.
All research outputs
of 12,980,291 outputs
Outputs from Nature
of 68,111 outputs
Outputs of similar age
of 381,948 outputs
Outputs of similar age from Nature
of 710 outputs
Altmetric has tracked 12,980,291 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 99th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 68,111 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 74.1. This one has done particularly well, scoring higher than 91% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 381,948 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 99% of its contemporaries.
We're also able to compare this research output to 710 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 73% of its contemporaries.