RAS: National Astronomy Meeting 2017

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National Astronomy Meeting 2017
Royal Astronomical Society | University of Hull | 2017 July 02-06

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Surprise Methanol Detection Points to an Evolving Story of Enceladus's Plumes
RAS | NAM2017 | 2017 Jul 03

[img3="NASA image of Enceladus within the E-ring in orbit around Saturn, where it is
possible that the methanol detection could originate further out in the E-ring.
Credit: NASA / JPL-Caltech / Space Science Institute"]http://www.ras.org.uk/images/stories/pr ... eladus.jpg[/img3][hr][/hr]

A serendipitous detection of the organic molecule methanol around an intriguing moon of Saturn suggests that material spewed from Enceladus undertakes a complex chemical journey once vented into space. This is the first time that a molecule from Enceladus has been detected with a ground-based telescope. Dr Emily Drabek-Maunder, of Cardiff University, will present the results on Tuesday 4 July at the National Astronomy Meeting at the University of Hull.

Enceladus’s plumes are thought to originate in water escaping from a subsurface ocean through cracks in the moon’s icy surface. Eventually these plumes feed into Saturn’s second-outermost ring, the E-ring.

Drabek-Maunder says: “Recent discoveries that icy moons in our outer Solar System could host oceans of liquid water and ingredients for life have sparked exciting possibilities for their habitability. But in this case, our findings suggest that that methanol is being created by further chemical reactions once the plume is ejected into space, making it unlikely it is an indication for life on Enceladus.” ...

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Musical Sun Reduces Range of Magnetic Activity
RAS | NAM2017 | 2017 Jul 03

[img3="Image of the sun in 171 angstrom as seen by NASA's SDO on 3rd July 2017. This channel is especially good at showing coronal loops - the arcs extending off of the Sun where plasma moves along magnetic field lines. The brightest spots seen here are locations where the magnetic field near the surface is exceptionally strong.
Credit: NASA / SDO"]http://www.ras.org.uk/images/stories/pr ... 4_0171.jpg[/img3][hr][/hr]

A study of the Sun using sound waves suggests that the layer in which the significant magnetic activity is located has grown thinner in recent years. Prof Yvonne Elsworth will present results at the National Astronomy Meeting at the University of Hull on Tuesday 4 July.

Prof Yvonne Elsworth, of the School of Physics and Astronomy at the University of Birmingham, explains: “The Sun is very much like a musical instrument except that its typical notes are at a very low frequency – some 100,000 times lower than middle C. Studying these sound waves, using a technique called helioseismology, enables us to find out what’s going on throughout the Sun’s interior.”

The Sun acts as a natural cavity to trap sound, which is generated by turbulence in the outermost few-hundred-kilometres of the convection zone. The University of Birmingham is one of the pioneers in the field of helioseismology and researchers have been using the Birmingham Solar Oscillations Network (BiSON) to study the Sun through sound waves since 1985. This period covers three of the Sun’s 11-year activity cycles, which see fluctuations in the rate at which energetic particles are created by the interaction between the Sun’s magnetic field and its hot, highly charged outer layers.

The Sun is currently heading towards a period of minimum activity and an international team has used the full BiSON dataset to try to look for clues in previous cycles as to what might be causing some unusual solar activity observed lately. ...

The Sun in Transition? Persistence of Near-Surface Structural Changes Through Cycle 24 - Rachel Howe et al

• Monthly Notices of the RAS 470(2):1935 (2017 Sep) DOI: 10.1093/mnras/stx1318
  arXiv.org > astro-ph > arXiv:1705.09099 > 25 May 2017

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Shining a Light on Solar Energetic Particles and Jets
RAS | NAM2017 | 2017 Jul 03

[img3="Image of the jet (blue arrow) emerging from the observed footpoint (red contour). The structures also agreed with the model predictions for hotter upflowing material in terms of temperature, velocity and timing. Credit: M. Druett et al / SDO"]http://www.ras.org.uk/images/stories/pr ... AIAJet.png[/img3][hr][/hr]

A team of astronomers, led by PhD researcher Malcolm Druett of Northumbria University at Newcastle, have taken a big step forward in understanding a 30-year-old mystery in the process of formation of solar flares. Druett will present their work on Monday 3 July at the National Astronomy Meeting in Hull, and the research appears in a paper in Nature Communications on the same day.

Scientists study the Sun with a variety of techniques, including looking at the so-called H-alpha line in the solar spectrum, associated with hydrogen gas that makes up the bulk of the mass of our nearest star. The observed wavelength of this line changes as a result of the Doppler effect, where light emitted from gas is slightly bluer if the gas is moving towards us (blueshifted) and slightly redder if it is moving away from us (redshifted). ...

Beam Electrons as a Source of Hα Flare Ribbons - Malcolm Druett et al

• Nature Communications 8:15905 (27 Jun 2017) DOI: 10.1038/ncomms15905

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Under Pressure - Extreme Atmosphere Stripping May Limit Exoplanets' Habitability
RAS | NAM2017 | 2017 Jul 03

[c][attachment=0]HD_189733b[1].jpg[/attachment][/c][hr][/hr]

New models of massive stellar eruptions hint at an extra layer of complexity when considering whether an exoplanet may be habitable or not. Models developed for our own Sun have now been applied to cool stars favoured by exoplanet hunters, in research presented by Dr. Christina Kay, of the NASA Goddard Flight Center, on Monday 3rd July at the National Astronomy Meeting at the University of Hull.

Coronal mass ejections (CMEs) are huge explosions of plasma and magnetic field that routinely erupt from the Sun and other stars. They are a fundamental factor in so called “space weather,” and are already known to potentially disrupt satellites and other electronic equipment on Earth. However, scientists have shown that the effects of space weather may also have a significant impact on the potential habitability of planets around cool, low mass stars -- a popular target in the search for Earth-like exoplanets.

Traditionally an exoplanet is considered “habitable” if its orbit corresponds to a temperature where liquid water can exist. Low mass stars are cooler, and therefore should have habitable zones much closer in to the star than in our own solar system, but their CMEs should be much stronger due to their enhanced magnetic fields. ...

Probability of CME Impact on Exoplanets Orbiting M Dwarfs and Solar-Like Stars - C. Kay, M. Opher, M. Kornbleuth

• Astrophysical Journal 826(2):195 (2016 Aug 01) DOI: 10.3847/0004-637X/826/2/195
  arXiv.org > astro-ph > arXiv:1605.02683 > 09 May 2016

http://asterisk.apod.com/viewtopic.php?p=262433#p262433

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"Little Cub" Lets Astronomers See Galaxy Demise
RAS | NAM2017 | Durham | UCSC | 2017 Jul 03

[img3="A false colour image shows the grand design spiral galaxy NGC 3359, which is about 50 million light years from us. NGC 3359 appears to be devouring a much smaller gas rich dwarf galaxy, nicknamed the Little Cub, which contains 10,000 times fewer stars than its larger companion. The contours show where the gas is being stripped from the Little Cub, whose stars are located in the central blue circle.
Credit: SDSS Collaboration"]https://news.ucsc.edu/2017/07/images/li ... rs-410.jpg[/img3][hr][/hr]

A primitive galaxy that could provide clues about the early universe has been spotted by astronomers as it begins to be consumed by a gigantic neighbouring galaxy.

The Little Cub galaxy -- so called because it sits in the Ursa Major or Great Bear constellation -- is being stripped of the gas needed to continue forming stars by its larger companion.

The find means scientists now have a rare opportunity to observe a dwarf galaxy as its gas is removed by the effects of a nearby giant galaxy to learn more about how this process happens.

As the Little Cub has remained almost pristine since its formation, scientists also hope its elements will reveal more about the chemical signature of the universe just minutes after the Big Bang. ...

The Little Cub and its larger neighbour, a grand design spiral galaxy called NGC 3359, are about 200 to 300 thousand light-years apart, and approximately 50 million light-years from Earth.

Gas from the Little Cub is being stripped away by its interaction with NGC 3359, which has up to 10,000 times as many stars as the Little Cub and is similar to our Milky Way.

By observing this cosmic feast, scientists hope to understand more about how and when gas is lost from smaller galaxies. ...

The Little Cub: Discovery of an Extremely Metal-Poor Star-Forming Galaxy in the Local Universe - T. Hsyu et al

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Fastest Stars in the Milky Way Are 'Runaways' from Another Galaxy
RAS | NAM2017 | Cambridge | 2017 Jul 04

[img3="An artist’s impression of a runaway star leaving a region of intense star formation in the Large Magellanic Cloud. Credit: Amanda Smith"]http://www.ras.org.uk/images/stories/pr ... 46x400.jpg[/img3][hr][/hr]

A group of astronomers have shown that the fastest-moving stars in our galaxy – which are travelling so fast that they can escape the Milky Way – are in fact runaways from a much smaller galaxy in orbit around our own.

The researchers, from the University of Cambridge, used data from the Sloan Digital Sky Survey and computer simulations to demonstrate that these stellar sprinters originated in the Large Magellanic Cloud (LMC), a dwarf galaxy in orbit around the Milky Way.

These fast-moving stars, known as hypervelocity stars, were able to escape their original home when the explosion of one star in a binary system caused the other to fly off with such speed that it was able to escape the gravity of the LMC and get absorbed into the Milky Way. The results are published in the Monthly Notices of the Royal Astronomical Society, and will be presented today (5 July) at the National Astronomy Meeting in Hull. ...

Hypervelocity Runaways from the Large Magellanic Cloud - Douglas Boubert et al

• Monthly Notices of the RAS 469(2):2151 (Aug 2017) DOI: 10.1093/mnras/stx848
  arXiv.org > astro-ph > arXiv:1704.01373 > 05 Apr 2017

http://asterisk.apod.com/viewtopic.php?p=270477#p270477
http://asterisk.apod.com/viewtopic.php?p=260168#p260168

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Shocking Case of Indigestion in Supermassive Black Hole
RAS | NAM2017 | 2017 Jul 04

[c][attachment=0]M51b_rgb_press_2.jpg[/attachment][/c][hr][/hr]

A multi-wavelength study of a pair of colliding galaxies has revealed the cause of a supermassive black hole’s case of ‘indigestion’. Results will be presented by Dr Hayden Rampadarath at the National Astronomy Meeting at the University of Hull.

Once every couple of hundred million years, the small galaxy NGC 5195 falls into the outer arms of its larger companion, NGC 5194, also known as the Whirlpool galaxy. Both galaxies are locked in a gravitational dance that will result – billions of years in the future – in the formation of a single galaxy.

As NGC 5195 plunges into the Whirlpool, matter streams onto the supermassive black hole at NGC 5195’s centre and forms an accretion disc. The disc grows to a point where the supermassive black hole can no longer accrete or ‘digest’ efficiently and matter is blasted out into the surrounding interstellar medium. Last year, NASA’s Chandra X-Ray observatory spotted arcs of X-ray emission that appeared to result from this ‘force-feeding’.

Now, new high-resolution images of the core of NGC 5195, taken with the e-MERLIN radio array, and archive images of the surrounding area from the Very Large Array (VLA), Chandra and the Hubble Space Telescope, reveal in detail how these blasts occur and spread. The study was led by astronomers at the University of Manchester’s Jodrell Bank Centre for Astrophysics. ...

A High Resolution Wide-Field Radio Survey of M51 - H. Rampadarath et al

• Monthly Notices of the RAS 452(1):32 (Sep 2015) DOI: 10.1093/mnras/stv1275
  arXiv.org > astro-ph > arXiv:1506.01870 > 05 Jun 2015

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Re-Making Planets after Star-Death
RAS | NAM2017 | 2017 Jul 05

[img3="Data at wavelength of 0.45 mm, combined from SCUBA and SCUBA-2, in a false-colour image. The Geminga pulsar (inside the black circle) is moving towards the upper left, and the orange dashed arc and cylinder show the ‘bow-wave’ and a ‘wake’. The region shown is 1.3 light-years across; the bow-wave probably stretches further behind Geminga, but SCUBA imaged only the 0.4 light-years in the centre.
Credit: Jane Greaves / JCMT / EAO"]http://www.ras.org.uk/images/stories/pr ... Labels.jpg[/img3][hr][/hr]

Astronomers Dr. Jane Greaves, of the University of Cardiff, and Dr. Wayne Holland, of the UK Astronomy Technology Centre in Edinburgh, may have found an answer to the 25-year-old mystery of how planets form in the aftermath of a supernova explosion. The two researchers will present their work on Thursday 6 July at the National Astronomy Meeting at the University of Hull, and in a paper in Monthly Notices of the Royal Astronomical Society.

The first planets outside the solar system were discovered 25 years ago -- not around a normal star like our Sun, but instead orbiting a tiny, super-dense 'neutron star.' These remnants are left over after a supernova, the titanic explosion of a star many times more massive than our own.

Such 'planets in the dark' have turned out to be incredibly rare, and astronomers are puzzled over where they come from. The supernova explosion should destroy any pre-existing planets, and so the neutron star needs to capture more raw materials to form its new companions. These after-death planets can be detected because their gravitational pull alters the times of arrival of radio pulses from the neutron star, or 'pulsar,' that otherwise pass us by extremely regularly. ...

The Geminga Pulsar Wind Nebula in the Mid-Infrared and Submillimetre - J. S. Greaves & W. S. Holland

• Monthly Notices of the RAS Letters (online 15 Jun 2017) DOI: 10.1093/mnrasl/slx098 (preprint)

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First Look at Gravitational Dance That Drives Stellar Formation
RAS | NAM2017 | 2017 Jul 05

[c][attachment=0]Williams_Figure1.jpg[/attachment][/c][hr][/hr]

Swirling motions in clouds of cold, dense gas have given, for the first time, an active insight into how gravity creates the compact cores from which stars form in the interstellar medium. The results will be presented today, Thursday 6th July, by Gwen Williams at the National Astronomy Meeting at the University of Hull.

Williams, of Cardiff University, explains: “We’ve known for some time that dusty, filamentary cloud structures are ubiquitous in the Milky Way’s interstellar medium. We also know that the densest of these filaments fragment into compact pockets of cold gas that then collapse under their own gravity to form individual stars. However, there’s still been a question mark over how, exactly, this happens.”

SDC13 is a remarkable cloud network of four filaments converging on a central hub, with a total mass of gas equivalent to a thousand of our Suns. Observations by Williams and colleagues at Cardiff University and the University of Manchester, using the Jansky Very Large Array (JVLA) and the Green Bank Telescope (GBT), have now captured the effects of gravity on ammonia gas moving within the SDC13 system.

Material is pulled from surrounding filaments and accreted onto cores dotted along the cloud structure, converting gravitational potential energy into kinetic energy in the process. Intense surges in the gas motion are observed at two-thirds of the cores that have yet to form stars. ...

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Adventures in Acoustic Cosmology
RAS | NAM2017 | 2017 Jul 05

[img3="Optical Hubble Space Telescope image of the Antennae Galaxies overlaid with a radio-image taken by ALMA. In the ‘image’, each pixel is actually represents a spectrum of frequencies across the electromagnetic radio spectrum: the ‘image’ is actually a data-cube. Credit: ALMA / ESO / NAOJ / NRAO / ESA / NASA / STScI"]https://www.ras.org.uk/images/stories/p ... 24x578.jpg[/img3][hr][/hr]

A project that explores whether there is a musical equivalent to the curvature of spacetime will be presented on Thursday 6th July by Gavin Starks at the National Astronomy Meeting at the University of Hull.

Starks, who has a background in radio astronomy and electronic music, has been working on developing an ‘acoustic cosmology’ for more than 20 years in collaboration with Prof. Andy Newsam of Liverpool John Moores University. Their aim is to test whether mathematical relationships that describe cosmology and quantum mechanics can be applied to a sonic universe, or ‘soniverse.’

Starks explains: “If we look at the way that music has evolved from mediaeval plainsong to the algorithms that generate current chart-hits, we can see parallels developing in the way we describe music and descriptions of our perception of the universe. We can now create new types of sound from scratch -- electronic sounds that simply couldn’t have existed before. It leads us to think about a digital sound world that we can’t enter, because it physically doesn’t exist. The question is -- what next? ...

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Milky Way Could Have 100 Billion Brown Dwarfs
RAS | NAM2017 | York University | 2017 Jul 05

[img3="False-colour near-infrared image of the core of the young massive cluster RCW 38 taken with the adaptive-optics camera NACO at the ESO's Very Large Telescope. RCW 38 lies at a distance of about 5500 light years from the Sun. The field of view of the central image is approximately 1 arc minute, or 1.5 light years across. The insets, each spanning about 0.07 light years on a side, show a subset of the faintest and least massive cluster candidate brown dwarfs (indicated by arrows) of RCW 38 discovered in this new image. These candidate brown dwarfs might weigh only a few tens of Jupiter masses, or about 100 times less than the most massive stars seen towards the centre of the image. Credit: Koraljka Muzic et al / ESO / VLT"]https://nam2017.org/images/press/Thursd ... ands_2.jpg[/img3][hr][/hr]

Our galaxy could harbour some 100 billion brown dwarfs, often described as "failed stars," reveals new research by an international team of astronomers, including York University's Ray Jayawardhana in the Faculty of Science.

Brown dwarfs are objects intermediate in mass between stars and planets, with masses too low to sustain stable hydrogen fusion in their core, the hallmark of stars like the Sun.

From their survey, the seven-member research team estimates that our galaxy, the Milky Way, has at least 25 billion to as many as 100 billion brown dwarfs. Even this could be a significant underestimation, as there are many lower mass and fainter brown dwarfs, present everywhere in star clusters, they note.

"It seems that brown dwarfs form in abundance in a variety of star clusters," says Jayawardhana. "They are ubiquitous denizens of our Milky Way galaxy."

Jayawardhana and the team have come to the conclusion after surveying brown dwarfs in a massive star cluster, noting this is probably typical of the environment where most stars in the galaxy form.

The researchers found that there is approximately one brown dwarf for every two stars in the cluster, similar to the ratio they had found previously in nearer, less dense star clusters. ...

The Low-Mass Content of the Massive Young Star Cluster RCW 38 - Koraljka Muzic et al

• arXiv.org > astro-ph > arXiv:1707.00277 > 02 Jul 2017