Starship Asterisk*

Who says there’s no romance in the outer solar system? A new study has identified 2004 TT₃₅₇ as a body that may be made up of two separate objects in contact with each other.

• Astrophysical Journal 844(2):135 (01 Aug 2017) DOI: 10.3847/1538-4357/aa7ed3
  arXiv.org > astro-ph > arXiv:1707.09927 > 31 Jul 2017

In the search for dark matter, the most commonly accepted candidates are invisible, massive particles commonly referred to as WIMPs. But as time passes and we still haven’t detected WIMPs, alternative scenarios are becoming more and more appealing. Prime among these is the idea of axions. ...

• Astrophysical Journal Letters 845(1):L4 (2017 Aug 10) DOI: 10.3847/2041-8213/aa808d
  arXiv.org > astro-ph > arXiv:1708.01399 > 04 Aug 2017

16th Meeting of AAS High Energy Astrophysics Division (HEAD).

AAS Nova Editor’s note: This week [ the week beginning 21 August 2017] we’re in Sun Valley, Idaho at the 16th meeting of the AAS High Energy Astrophysics Division (HEAD). Follow along to catch some of the latest news from the field of high energy astro!

http://aasnova.org/2017/08/21/2017-head-welcome/
Greetings from the 16th meeting of the High Energy Astrophysics Division (HEAD) of the American Astronomical Society in Sun Valley, Idaho! This week, I will be writing updates on just a few of the events at the meeting and posting each morning. The usual posting schedule for AAS Nova will resume next week.

http://aasnova.org/2017/08/22/2017-head-day-1/

http://aasnova.org/2017/08/23/2017-head-day-2/

http://aasnova.org/2017/08/24/2017-head-day-3/

The discovery of an extremely metal-poor star-forming galaxy in our local universe, dubbed Little Cub, is providing astronomers with front-row seats to the quenching of a near-pristine galaxy. ...

• Astrophysical Journal Letters 845(2):L22 (2017 Aug 20) DOI: 10.3847/2041-8213/aa821f
  arXiv.org > astro-ph > arXiv:1708.01260 > 03 Aug 2017

Hanging out in a binary system with a hot millisecond pulsar can be hazardous to your health! A new study has examined how these perilous objects can heat and evaporate away their companions. ...

• Astrophysical Journal 845(1):42 (10 Aug 2017) DOI: 10.3847/1538-4357/aa7a02
  arXiv.org > astro-ph > arXiv:1706.05467 > 17 Jun 2017 (v1), 05 Jul 2017 (v2)

How did the first supermassive black holes grow alongside their host galaxies in the early universe? New observations from the Atacama Millimeter/Submillimeter Array (ALMA) have provided us with a detailed look at one quasar, which may help us to answer this question. ...

• Astrophysical Journal 845(2):138 (20 Aug 2017) DOI: 10.3847/1538-4357/aa826c
  arXiv.org > astro-ph > arXiv:1707.03078 > 10 Jul 2017 (v1), 12 Jul 2017 (v2)

Can’t get enough eclipse news? Check out this coverage of the solar eclipse of 1854! Special thanks to Tumblr blogger Nemfrog for digging this out of the archives.

These two sets of photographs both capture the annular solar eclipse that occurred on May 26, 1854, passing close to the U.S./Canada border. The photographs come from articles (linked below) published by two scientists who both watched the eclipse from the state of New York and made extensive measurements of its properties. ...

• Astronomical Journal 4(75):17 (Sep 1854) DOI: 10.1086/100439

• Astronomical Journal 4(77):33 (Nov 1854) DOI: 10.1086/100450

If you missed the New York Times publication of this video back in May, it’s definitely worth a watch! The video, created by Matt Russo (CITA, University of Toronto), Dan Tamayo, (University of Toronto Scarborough), and Andrew Santaguida (RVNNERS), provides a musical description — a sonification — of the TRAPPIST-1 exoplanetary system. It was produced in conjunction with a study led by Tamayo that was published in ApJ Letters, exploring the dynamical stability of the TRAPPIST-1 system. ...

• Astrophysical Journal Letters 840(2):L19 (2017 May 10) DOI: 10.3847/2041-8213/aa70ea
  arXiv.org > astro-ph > arXiv:1704.02957 > 10 Apr 2017 (v1), 08 May 2017 (v2)

Solar eruptions don’t always succeed! The Very High Angular Resolution Ultraviolet Telescope (VAULT2.0) sounding rocket captured an event in 2014 in which a solar filament was shredded by the Sun’s own magnetic forces before it had the chance to result in a coronal mass ejection. These observations, detailed in a recently published paper in ApJ led by Georgios Chintzoglou (Lockheed Martin Solar and Astrophysics Laboratory and UCAR, Boulder), mark the first time we’ve witnessed a filament being torn down by the Sun — allowing us to investigate in detail how and why this happened. Check out the video below (by NASA’s Goddard Space Flight Center/Genna Duberstein) for an overview of the failed eruption and what we learned.

• Astrophysical Journal 843(2):93 (10Jul 2017) DOI: 10.3847/1538-4357/aa77b2
  arXiv.org > astro-ph > arXiv:1706.00057 > 31 May 2017 (v1), 26 Jun 2017 (v2)

Is Terzan 5, a star cluster that lies ~19,000 light-years away, a true globular cluster born in the Milky Way? Or are we seeing the remains of a dwarf galaxy that was captured by our galaxy? New observations by the Green Bank Telescope in West Virginia have tracked the radio signals of a treasure trove of millisecond pulsars — 36 of them — in the heart of Terzan 5. These signals can be used to trace the density distribution of the cluster, revealing where the matter resides. The observations, detailed in a recent article led by Brian Prager (University of Virginia, Charlottesville) and illustrated in the video below (credited to B. Saxton (NRAO/AUI/NSF); GBO/AUI/NSF; NASA/ESA Hubble), suggest that there is no supermassive black hole in the cluster center. This supports the idea that Terzan 5 is a true globular cluster.

• Astrophysical Journal 845(2):148 (20 Aug 2017) DOI: 10.3847/1538-4357/aa7ed7
  arXiv.org > astro-ph > arXiv:1612.04395 > 13 Dec 2016 (v1), 12 Jul 2017 (v3)

What happens in the extreme environments of globular clusters when a star and a binary system meet? A team of scientists has new ideas about how these objects can deform, change their paths, spiral around each other, and merge. ...

• Astrophysical Journal 846(1):36 (01 Sep 2017) DOI: 10.3847/1538-4357/aa7e32
  arXiv.org > astro-ph > arXiv:1609.09114 > 28 Sep 2017

Speeding stars running away from our galaxy pose an intriguing puzzle: where did these stars come from, and how were they accelerated to their great speeds? The recent discovery of two new runaway stars have increased the mystery. ...

• Astrophysical Journal Letters 847(1):L9 (2017 Sep 20) DOI: 10.3847/2041-8213/aa894b
  arXiv.org > astro-ph > arXiv:1708.08602 > 29 Aug 2017

Today promises to be an exciting day in the world of gravitational-wave detections. To keep with the theme, we thought we’d use this opportunity to take a renewed look at an interesting question about the Laser Interferometer Gravitational-Wave Observatory (LIGO) and dark matter: if dark matter is made up of primordial black holes, will LIGO be able to detect them? ...

• Astrophysical Journal Letters 845(2):L13 (2017 Aug 20) DOI: 10.3847/2041-8213/aa831c
  arXiv.org > astro-ph > arXiv:1706.04947 > 15 Jun 2017 (v1), 31 Jul 2017 (v3)

Ultraluminous X-ray sources (ULXs) are astronomical sources of X-rays that, while dimmer than active galactic nuclei, are nonetheless brighter than any known stellar process. What are these beasts and why do they shine so brightly? ...

• Astrophysical Journal 846(1):17 (01 Sep 2017) DOI: 10.3847/1538-4357/aa821d
  arXiv.org > astro-ph > arXiv:1705.06155 > 17 May 2017 (v1), 01 Sep 2017 (v3)

Molecular clouds — which you’re likely familiar with from stunning popular astronomy imagery — lead complicated, tumultuous lives. A recent study has now found that these features must be rapidly built and destroyed. ...

• Astrophysical Journal Letters 847(1):L10 (2017 Sep 20) DOI: 10.3847/2041-8213/aa8a61
  arXiv.org > astro-ph > arXiv:1706.09561 > 29 Jun 2017 (v1), 02 Sep 2017 (v3)

Jupiter-like planets with blisteringly close-in orbits are generally friendless, with no nearby planets transiting along with them. Giant planets with orbits a little further out, on the other hand, often have at least one companion. A new study examines the cause of hot Jupiters’ loneliness. ...

• Astronomical Journal 154(3):93 (2017 Sep) DOI: 10.3847/1538-3881/aa8174
  arXiv.org > astro-ph > arXiv:1707.06370 > 20 Jul 2017

With the first detection of gravitational waves in 2015, scientists celebrated the opening of a new window to the universe. But multi-messenger astronomy — astronomy based on detections of not just photons, but other signals as well — was not a new idea at the time: we had already detected tiny, lightweight neutrinos emitted from astrophysical sources. Will we be able to combine observations of neutrinos and gravitational waves in the future to provide a deeper picture of astrophysical events? ...

• Astrophysical Journal Letters 848(1):L4 (2017 Oct 10) DOI: 10.3847/2041-8213/aa8d14
  arXiv.org > astro-ph > arXiv:1708.07075 > 23 Aug 2017 (v1), 18 Sep 2017 (v2)

Taking advantage of a program offered by the National Radio Astronomy Observatory (NRAO), an undergraduate class has observed local dwarf galaxies to learn about their properties. ...

• Astrophysical Journal Letters 848(1):L10 (2017 Oct 10) DOI: 10.3847/2041-8213/aa8ea0
  arXiv.org > astro-ph > arXiv:1709.10161 > 28 Sep 2017 (v1), 02 Oct 2017 (v2)

Astronomers, have you missed out on WorldWide Telescope (WWT) because you’re not on a Windows computer? Good news: WWT can now be accessed via a web interface, with no dependence on your operating system! Now’s your chance to try it out. ...

Where were you on Thursday, 17 August 2017? I was in Idaho, getting ready for Monday morning’s solar eclipse. What I didn’t know was that, at the time, around 70 teams around the world were mobilizing to point their ground- and space-based telescopes at a single patch of sky suspected to host the first gravitational-wave-detected merger of two neutron stars. ...

Growing a planet from a dust grain is hard work! A new study explores how vortices in protoplanetary disks can assist this process.

• Astrophysical Journal Letters 848(1):L11 (2017 Oct 10) DOI: 10.3847/2041-8213/aa8edc
  arXiv.org > astro-ph > arXiv:1710.05028 > 13 Oct 2017

How do the supermassive black holes that live at the centers of galaxies influence their environments? New observations of a distant active galaxy offer clues about this interaction. ...

• Astrophysical Journal 848(1):61 (2017 Oct 10) DOI: 10.3847/1538-4357/aa8c76
  arXiv.org > astro-ph > arXiv:1709.09171 > 26 Sep 2017

It seems like science is increasingly being done with advanced detectors on enormous ground- and space-based telescopes. One might wonder: is there anything left to learn from observations made with digital cameras mounted on ~10-cm telescopes?

The answer is yes — plenty! Illustrating this point, a new study using such equipment recently reports on the structure and dynamics of the Sun’s corona during two solar eclipses. ...

• Astrophysical Journal 848(2):84 (2017 Oct 20) DOI: 10.3847/1538-4357/aa8c76

Huge reservoirs of cold hydrogen gas — the raw fuel for star formation — lurk in galaxies throughout the universe. A new study examines whether these reservoirs have always been similar, or whether those in distant galaxies are very different from those in local galaxies today. ...

• Astrophysical Journal Letters 848(1):L7 (2017 Oct 10) DOI: 10.3847/2041-8213/aa8cc3
  arXiv.org > astro-ph > arXiv:1709.07933 > 22 Sep 2017 (v1), 02 Oct 2017 (v2)

Neptune’s moon system is not what we would expect for a gas giant in our solar system. Scientists have now explored the possibility that Neptune started its life with an ordinary system of moons that was later destroyed by the capture of its current giant moon, Triton. ...

• Astronomical Journal 154(5):208 (Nov 2017) DOI: 10.3847/1538-3881/aa9184
  arXiv.org > astro-ph > arXiv:1711.01581 > 05 Nov 2017