We study the convection zones in the outer envelope of hot massive stars which are caused by opacity peaks associated with iron and helium ionization. We determine the occurrence and properties of these convection zones as function of the stellar parameters. We then confront our results with observations of OB stars. A stellar evolution code is used to compute a grid of massive star models at different metallicities. In these models, the mixing length theory is used to characterize the envelope convection zones. We find the iron convection zone (FeCZ) to be more prominent for lower surface gravity, higher luminosity and higher initial metallicity. It is absent for luminosities below about $10^{3.2}\lso$, $10^{3.9}\lso$, and $10^{4.2}\lso$ for the Galaxy, LMC and SMC, respectively. We map the strength of the FeCZ on the Hertzsprung-Russell diagram for three metallicities, and compare this with the occurrence of observational phenomena in O stars: microturbulence, non-radial pulsations, wind clumping, and line profile variability. The confirmation of all three trends for the FeCZ as function of stellar parameters by empirical microturbulent velocities argues for a physical connection between sub-photospheric convective motions and small scale stochastic velocities in the photosphere of O- and B-type stars. We further suggest that clumping in the inner parts of the winds of OB stars could be caused by the same mechanism, and that magnetic fields produced in the FeCZ could appear at the surface of OB stars as diagnosed by discrete absorption components in ultraviolet absorption lines.

At Authorea we have big goals, not necessarily for ourselves, but for researchers and the scientific community. We envision a world where researchers write and publish their work openly, they include their data inside of interactive figures and seek collaborators and the community to test their work to ensure it is robust. Communication and publishing is dynamic and modern and research moves more efficiently because researchers move more efficiently. This vision may sound idealistic but it is being realized and we are diligently working to build a platform and community to foster it.  Over the last year we have taken tremendous steps towards creating the place to write and disseminate research. We relaunched our new editor only a few months ago and have redesigned nearly every part of Authorea to make it the best place to write research documents, for all researchers.  We've added direct submission to a growing list of leading journals, have introduced the first and only place to preprint in HTML, and introduced a new version control system for writing research papers.  In short, we've done a lot, really fast.We're going to continue to keep innovating but we're taking a brief pause from introducing new features to focus on reliability, usability, and research support. That means, we want to hear from you. What could we do better? What small or big changes on Authorea would help you be more efficient at research writing and publishing? Below are just some of the major highlights of what we've accomplished in the last few months, which do not include the bugs here and there and tweaks made based on user feedback/testing.  Acquire Research Publisher, The Winnower--LinkNew HomepageLaunch Authorea Beta, our new editor--Linkreal-time collaborationautosaveability to write in Markdown, LaTeX, and rich-text all within one articlenew toolbarPartner with Sample of Science--LinkPartner with eLife for direct submission--LinkImproved UX for LaTeX and Markdown rendering.Improved Author Management controlAdd multi-cite capability/improve design UX of citation tool.New pricing--LinkNew browse page--LinkIntroduce new version control system for research writing--LinkNew features page--LinkIntroduce preprinting capabilities and ability to issue DOI on Authorea--LinkAdd \labels, \refs, New commenting system

Preprints are publication-ready research papers that are made public before publication

DO YOU NEED LATEX? MAYBE NOT... If you are interested in just inserting simple mathematics or simple inline LaTeX, you do not need to use a full fledged LaTeX mode described in the rest of this document. You can write both math symbols, simple formulae, and even simple LaTeX using the equation button x²y in the toolbar. Read more here. BUT IF YOU WANT TO VENTURE INTO THE LATEX WORLD, KEEP READING... Authorea supports LaTeX, a powerful typesetting program that renders beautiful math notation. In order to insert LaTeX: click on the Insert button in the toolbar and then select LaTeX from the dropdown. A LaTeX label shows next to the LaTeX block in which you can write LaTeX notation. Here are some tips for writing LaTeX in Authorea: 1. Click anywhere outside of the LaTeX block to render it. 2. Hover on Preview to see a Preview of the rendered content. 3. Do not paste an entire LaTeX article! Instead import documents from your homepage. 4. Only type LaTeX content in a LaTeX block, i.e. everything you would write after . 5. Do not type preamble (e.g. documentclass), frontmatter, macros or figures. 6. To add macros (newcommands) and packages, click Settings → Edit Macros 7. Use the Insert Figure button to insert images (and data). 8. Use math mode for equations, e.g. $\mathcal L_{EM}=-\frac14F^{\mu\nu}F_{\mu\nu}$. 9. Try the citation tool (click cite) to find and add citations, or use \cite{}. 10. To insert more LaTeX blocks click Insert → LaTeX. 11. You can use sectioning commands like \section{},\subsection{},\subsubsection{} to add headings.[1] THERE ARE DIFFERENT WAYS TO PRESENT A MATHEMATICAL EXPRESSION IN LATEX — _INLINE_, AS AN _EQUATION_ OR _DISPLAYSTYLE_. Inline mathematical expressions Inline expressions occur in the middle of a sentence. To produce an inline expression, place the math expression between dollar signs ($). For example, typing $E=mc^2$ yields E = mc². Equations Equations are mathematical expressions that are given their own line and are centered on the page. These are usually used for important equations that deserve to be showcased on their own line or for large equations that cannot fit inline. To produce an inline expression, place the mathematical expression between the symbols \[! and \verb!\]. Typing \[x=}{2a}\] yields \[x=}{2a}.\] Displaystyle To get full-sized inline mathematical expressions use \displaystyle. Typing I want this $\displaystyle ^{\infty} {n}$, not this $^{\infty} {n}$. yields: I want this $\displaystyle ^{\infty}{n}$, not this $^{\infty}{n}.$ SYMBOLS (IN _MATH_ MODE) The basics -------------------------- -------------- --------------- _description_ _command_ _output_ addition + + subtraction - − plus or minus \pm ± multiplication (times) \times × multiplication (dot) \cdot ⋅ division symbol \div ÷ division (slash) / / infinity \infty ∞ dots 1,2,3,\ldots 1, 2, 3, … dots 1+2+3+\cdots 1 + 2 + 3 + ⋯ fraction {b} ${b}$ square root $$ nth root \sqrt[n]{x} $\sqrt[n]{x}$ exponentiation a^b ab subscript a_b ab absolute value |x| |x| natural log \ln(x) ln(x) logarithms b logab exponential function e^x=\exp(x) ex = exp(x) degree \deg(f) deg(f) circle plus \oplus ⊕ circle times \otimes ⊗ equal = = not equal \ne ≠ less than < < less than or equal to \le ≤ greater than or equal to \ge ≥ approximately equal to \approx ≈ -------------------------- -------------- --------------- [1] You can toggle heading numbering on/off from the article settings. This footnote is generated via \footnote{}

Thermohaline mixing has recently been proposed to occur in low-mass red giants, with large consequence for the chemical yields of low-mass stars. We investigate the role of thermohaline mixing during the evolution of stars between 1$\mso$ and 3$\mso$, in comparison with other mixing processes acting in these stars. We use a stellar evolution code which includes rotational mixing, internal magnetic fields and thermohaline mixing. We confirm that during the red giant stage, thermohaline mixing has the potential to decrease the abundance of ³He, which is produced earlier on the main sequence. In our models we find that this process is working on the RGB only in stars with initial mass $ \le 1.5\mso$. Moreover we report that thermohaline mixing is also present during core He-burning and beyond, and has the potential to change the surface abundances of AGB stars. While we find rotational and magnetic mixing to be negligible compared to the thermohaline mixing in the relevant layers, the interaction of thermohaline motions with the differential rotation may be essential to establish the timescale of thermohaline mixing in red giants. To explain the surface abundances observed at the bump in the luminosity function, the speed of the mixing process needs to be more than two orders of magnitude higher than in our models. However it is not clear if thermohaline mixing is the only physical process responsible for these surface-abundance anomalies. Therefore it is not possible at this stage to calibrate the efficiency of thermohaline mixing against the observations.

What is the preprint server ArXiv?The ar\(\chi\)iv (pronounced "archive", since \(\chi\) = "chi") is the most popular preprint repository in the world. (Read: What is a preprint?) It was started in 1991 by physicist Paul Ginsparg to become a way to quickly and freely give the scientific community access to the submission-ready research papers, as e-prints. While the arXiv initially covered only the fields of physics and astronomy, it grew over time to encompass other fields, such as computer science, quantitative biology, statistics, and quantitative finance. The rise of arXiv has been mostly limited to fields that use LaTeX, a typesetting system for math-heavy documents. This is because (1) the most efficient way to submit papers to arXiv is by uploading a LaTeX file which gets compiled to PDF, and (2) pre-printing has historically been a practice popular in the hard sciences --- at CERN, it was performed via inter-library exchange of printed copies before the web even existed \cite{pepe2005cern}. However, in recent years, pre-prints are catching on as a legal and free mechanism to openly and quickly share research also in the life sciences (see ASAPbio, and BiorXiv, for example).How do ArXiv and Authorea compare?At first glance, ArXiv and Authorea may not seem related to one another. ArXiv is a content repository, while Authorea is a content creation system. However, Authorea - with the launch of a number of publishing features - is quickly becoming an open repository, as well. Below, we highlight some points of comparison between Authorea and ArXiv.1. More than just a collection of PDFs: web native papers.There is growing consensus in scholarly communication circles that academic publishing needs to move "beyond the PDF" (see Force 11 conference). The PDF is a great portable format for printing, but it is not the best format to share, discuss, and read on the web. Every article on arXiv, being a PDF, is non-actionable. In this respect, the arXiv is a "PDF dump".2. For LaTeX users. And for everyone else too!The ArXiv relies heavily on LaTeX. For Authorea, LaTeX is one of many  formats you can write in. Others include Markdown, and HTML (rich text, like Word!). Authorea offers a format-neutral, web-native platform. Regardless of the format, you render content on the web - not on a separate pane that compiles a PDF (side note, you can still export a PDF). The advantage: Authorea documents are not constrained to the hard sciences and to the LaTeX community. Authorea is for all scholars: from astrophysics to zoology. Authorea's rich text editor is a true WYSIWYG editor (What you see is what you get). It also has the ability to include as much LaTeX and mathematical notation as you need. Every document written in Authorea becomes a beautiful webpage.

The fact we are alive and pondering a vast Universe from spaceship Earth raises a number of fascinating questions. Astrophysicist are now asking why “HERE” and why “NOW”. What is the chance of life emerging around a star like the Sun, about 12-13 billion years after our Universe was born?

Today's research is truly awesome. Researchers can now analyze and perform experiments that would have been thought impossible only a few decades ago. From the deep sequencing of nearly any animal genome with ease \cite{DePristo_2011} to the discovery of the Higgs Boson \cite{ATLAS_Collaboration_2012}, we are in a period of great innovation and understanding.  And yet, how we share our ideas (i.e. publishing) has not changed very much in nearly 350 years.  In short, scientists are doing 21st-century research, writing on 20th-century tools, and packaging it in 17th-century formats.The fact that research communication hasn't changed in hundreds of years may signal that it works, right? Well in some regards--yes, the work is persistent and we have copies of some of the world's most important ideas (yay librarians!). Yet, in many other regards research communication is failing us: data sharing is rare \cite{Alsheikh_Ali_2011}, the majority of work is hard to access (it's pay-walled) \cite{Bj_rk_2010}, publishing takes months to years to complete \cite{Himmelstein_2016}, and classical peer review does not detect major errors \cite{Smith_2010}. As a consequence, we're now seeing major problems with the reproducibility of findings in disciplines like cancer research and psychology \cite{Begley_2012,eLife_2017,Open_Science_Collaboration_2015}.To understand how we got to where we are today, it is useful to look at the history of research publishing, how and why it got started, and the changes that occured along the way. Here, we outline an very brief history of research publishing, with particular emphasis on preprints, in hopes of providing a stage to discuss what publishing might look like in the near future.A brief history of the research journalThe first journal article, published in 1655, by Philosophical Transactions marked a step towards the formalization of the communication of research in article format \cite{Oldenburg_1665}. As noted in the introductory editorial, research communication was seen as necessary for the advancement of research: "Whereas there is nothing more necessary for promoting the improvement of Philosophical Matters, than the communication of such" \cite{1665}.

G_{\mu\nu}+\Lambda T_{\mu\nu}={c^4}T_{\mu\nu}

_Check here for the full article and layman summaries in different languages._

This example manuscript is intended to serve as a tutorial and template for authors to use when writing their own AAS Journal articles with Authorea. The manuscript includes a history of   and documents the new features in the previous version, 6.0, as well as the new features in version 6.1. This manuscript includes figure and table examples to illustrate these new features. AUTHOREA FEATURES A RICH TEXT EDITOR SO THAT YOU CAN WRITE IN LATEX, MARKDOWN, OR RICH TEXT AND RENDER DIRECTLY ON THE WEB. AUTHOREA SUPPORTS AND RENDERS THE VAST MAJORITY OF LATEX NOTATION NEEDED FOR AAS JOURNAL ARTICLES. A FEW FEATURES PROVIDED BY AASTEX V6.1. THAT ARE NOT AVAILABLE IN AUTHOREA HAVE BEEN LISTED IN THIS DOCUMENT. Authors are welcome replace the text, tables, figures, and bibliography with their own and submit the resulting manuscript to the AAS Journals peer review system. The first lesson in the tutorial is to remind authors that the AAS Journals, the Astrophysical Journal (ApJ), the Astrophysical Journal Letters (ApJL), and Astronomical Journal (AJ), all have a 250 word limit for the abstract. If you exceed this length the Editorial office will ask you to shorten it.

This example manuscript is intended to serve as a tutorial and template for authors to use when writing their own AAS Journal articles. The manuscript includes a history of   and documents the new features in the previous version, 6.0, as well as the new features in version 6.1. This manuscript includes many figure and table examples to illustrate these new features. Information on features not explicitly mentioned in the article can be viewed in the manuscript comments or more extensive online documentation. Authors are welcome replace the text, tables, figures, and bibliography with their own and submit the resulting manuscript to the AAS Journals peer review system. The first lesson in the tutorial is to remind authors that the AAS Journals, the Astrophysical Journal (ApJ), the Astrophysical Journal Letters (ApJL), and Astronomical Journal (AJ), all have a 250 word limit for the abstract. If you exceed this length the Editorial office will ask you to shorten it.

The scientific community holds elections for various academies, positions, and prizes. Much like in politics, the elections have not always been open to everyone. Here we highlight 8 "firsts" in elections in light of the current United States presidential election. 

This post was written by Matteo Cantiello, a theoretical astrophysicist at the Kavli Institute for Theoretical Physics and Authorea’s Chief Scientist. It is intended to be published as a post on Astrobetter.com. I am aware that a while back a lot of astronomers have tried out writing their research articles on Authorea, a web-based collaborative writing platform. Some were disappointed by the lack of certain advanced LaTeX features (e.g., deluxetables, now supported). You were disappointed, you told us why, and we just implemented some big changes to make you happy. Authorea now has a “Power LaTeX user” mode which supports a much much larger subset of LaTeX. Essentially everything. And unlike some services such as ScribTeX and WriteLaTeX (previously reviewed on Astrobetter), all your LaTeX renders both to PDF _and_ to HTML (i.e., the web). So, why should you give Authorea a spin and start using it daily for your research? It’s a good question. Here some highlights that might guide that decision. 1. With Authorea, your paper is accessible from any computer, anywhere in the world. 2. You can write your paper from your browser, no installation of TeX required. 3. You can write in LaTeX or in markdown. Advanced LaTeX and tables are now supported. 4. Collaboration is made easy. No need for endless emails threads with multiple draft revisions. 5. Every Authorea paper is a Git repo, version controlled. Again, no installations required. 6. Want to work offline via Github? You can. Authorea becomes the rendered version so that your coauthors can still work with you without having to learn Git. 7. Adding citations has never been easier. One click and done. Believe me, you will never want to go back. 8. You can include data and code in your paper, like IPython Notebooks. This allows for transparency and reproducibility of results. 9. Export to any journal format with just one click. We support all the usual suspects, from ApJ to AJ, from MNRAS to A&A. Switch back and forth between these styles in one click. 10. Powerful commenting system. For internal or even external review. 11. Authorea has templates to get you started fast with your next Astronomy grant proposal or d3.js paper. 12. Did I say deluxetables? Well, here’s the same deluxetable posted on Astrobetter a while back, as it is rendered on Authorea: https://www.authorea.com/38778_deluxe. Ok, enough with the list of fancy features. Here’s my personal experience as an astrophysicist using Authorea. I switched to writing papers with Authorea about a year ago and I noticed a number of immediate improvements: first of all MY PAPERS GET WRITTEN FASTER. Then I noticed that I have NO NEED TO EXCHANGE EMAILS WITH COLLABORATORS concerning the paper. All the action happens (and it’s logged) on Authorea, including discussions about revisions and suggestions for improvements. This said, I didn’t really expect the most important upturn. By getting rid of the overhead I had previously considered a messy unavoidable part of the scientific writing process, something remarkable happened. I actually STARTED ENJOYING WRITING MORE! And I don’t mean just publishing; I had experienced that joy before. The difference is I now cherish the time I spend putting my science into words. It might sound crazy, but Authorea did something amazing: it made me DISCOVER THE PLEASURE OF WRITING SCIENCE TOGETHER with my collaborators. So if you ask me “Why should I write my next paper with Authorea?” my honest answer is “Because you will love it!”. My suggestion is that you take Authorea for a spin and make up your own mind. The Astronomical community has a lot of experience with early adoption and innovation, so your feedback can help to substantially improve this tool. Do you think Authorea is on the right track? Is there a particular feature missing that would improve substantially your workflow? Share your reviews and suggestions in the comments!

The core rotation rates of massive stars have a substantial impact on the nature of core collapse supernovae and their compact remnants. We demonstrate that internal gravity waves (IGW), excited via envelope convection during a red supergiant phase or during vigorous late time burning phases, can have a significant impact on the rotation rate of the pre-SN core. In typical (10 M⊙ ≲ M ≲ 20 M⊙) supernova progenitors, IGW may substantially spin down the core, leading to iron core rotation periods $(P_{\rm min,Fe} \gtrsim 50 \, {\rm s})$. Angular momentum (AM) conservation during the supernova would entail minimum NS rotation periods of $P_{\rm min,NS} \gtrsim 3 \, {\rm ms}$. In most cases, the combined effects of magnetic torques and IGW AM transport likely lead to substantially longer rotation periods. However, stochastic influxes of AM delivered by IGW during shell burning phases also entail a maximum core rotation period. We estimate maximum iron core rotation periods of $P_{\rm max,Fe} \lesssim 10^4 \, {\rm s}$ in typical core collapse supernova progenitors, and a corresponding spin period of $P_{\rm max, NS} \lesssim 400 \, {\rm ms}$ for newborn neutron stars. This is comparable to the typical birth spin periods of most radio pulsars. Stochastic spin-up via IGW during shell O/Si burning may thus determine the initial rotation rate of most ordinary pulsars. For a given progenitor, this theory predicts a Maxwellian distribution in pre-collapse core rotation frequency that is uncorrelated with the spin of the overlying envelope.

WORDS ARE IMPORTANT. THEY CONVEY OUR THOUGHTS, OUR IDEAS, OUR INTUITIONS. PASSION, LOVE, DISCOVERY, THEY ALL MATERIALIZE FROM WORDS EMERGING FROM THE INNER WORKINGS OF OUR MINDS. AND WHEN WE WRITE, WHEN WE FILL WITH WORDS THE EMPTY CANVAS IN FRONT OF US, SOMETIMES THOSE INTUITIONS, THOSE FEELINGS, THOSE BEAUTIFUL BUNDLES OF THOUGHTS, THEY SUDDENLY BECOME CLEARER. ALL OF THE SUDDEN WE REALLY UNDERSTAND. THE WRITERS. THE READERS. THE LOVERS. TO LOVE, PASSION, DISCOVERY. TO WORDS. Happy Writing, - Matteo and The Authorea Team

ORCID – an acronym short for Open Researcher and Contributor ID – is an international, interdisciplinary and community-driven effort to create and maintain a registry of persistent, unique identifiers for researchers and scholars. ORCID IDs are extremely important in the disambiguation of non-unique author names. They can also be embedded in key workflows, such as research profile maintenance, manuscript submissions and grant applications. Using several approaches to reach out to our users, we will report on ORCID ID uptake by the astronomical community.

Stellar ultrasounds. Certain stars pulsate and can effectively be considered huge musical instruments: depending on their size and internal structure, they can oscillate at different frequencies, somewhat similar to spherical drums of different size, shape and material. The waves that propagate through the star can bring to surface precious information about the internal regions they crossed. This is similar to what seismologists do with the planet: they study at the surface waves excited by earthquakes to retrieve information about the structure and properties of the Earth’s inner regions they crossed. The waves crossing a star can be of different types, some are similar to sound waves, others to surf waves. Different waves probe different regions of the stellar plasma, so depending on which type of waves astronomers 'listen to', they can retrieve properties relative to different stellar depth. This is the basic idea behind the 'stellar ultrasound'. It turns out that the oscillations induced by these different types of waves can be encoded directly in the light of the star. This is awesome, because the sound can not travel in the vacuum that is the medium between stars, but light can. Also it travels much faster. This opens up a new branch of astronomy called "Asteroseismology", something only recently we started applying to large collections of stars because it requires observations from space. We can now determine the internal properties of thousands of stars. Some of these stars are thousands of light years away! And we found many surprises. The latest discovery is the potential ubiquity of ultra-strong magnetic fields hiding in the stellar cores. The stellar core is the region where thermonuclear reactions are at play, making the star shine and basically creating all the elements of which humans are made off as a byproduct (except Hydrogen). These magnetic fields are million of times stronger than the Earth's magnetic field, and can change completely the way a star lives and dies! For example, they might be playing a role in producing the brightest explosions in the cosmos...  Stars are huge musical instruments, playing music with their starlight. This twinkling carries the secret story of their magnetic coresSource: - Science (http://science.sciencemag.org/content/350/6259/423.abstract), - Nature (http://www.nature.com/nature/journal/v529/n7586/full/nature16171.html)