Starship Asterisk*

Susanna Kohler wrote:
There’s no hiding — changes in Earth’s atmosphere over the seasons are a dead giveaway to the fact that Earth hosts life. Now a new study explores whether we might use atmospheric seasonality like Earth’s to detect life on other planets. ...

• Astrophysical Journal Letters 858(2):L14 (10 May 2018) DOI: 10.3847/2041-8213/aac171
  arXiv.org > astro-ph > arXiv:1806.04592 > 12 Jun 2018

Susanna Kohler wrote:
On 1 April 1995, Hubble captured one of its most well-known images: a stunning photo of towering features known as the Pillars of Creation, located in the Eagle Nebula just 7,000 light-years away. A new study explores how these iconic columns are influenced by the magnetic fields within them. ...

• Astrophysical Journal Letters 860(1):L6 (2018 Jun 10) DOI: 10.3847/2041-8213/aac771
  arXiv.org > astro-ph > arXiv:1805.11554 > 29 May 2018

Kerry Hensley wrote:
Solar flares are often, but not always, associated with coronal mass ejections. Why do coronal mass ejections accompany some solar flares but not others? ...

• Astrophysical Journal 854(2):178 (2018 Feb 20) DOI: 10.3847/1538-4357/aaaa69
  arXiv.org > astro-ph > arXiv:1801.06641 > 20 Jan 2018 (v1), 24 Jan 2018 (v2)

Susanna Kohler wrote:
The recent discovery of GW170817 — the first gravitational-wave detection where we also observed electromagnetic signals — has enabled new studies of merging compact objects. What have we since learned about the radiation that emerges from these collisions? ...

• Astrophysical Journal 860(1):62 (2018 Jun 10) DOI: 10.3847/1538-4357/aac206
  arXiv.org > astro-ph > arXiv:1710.05442 > 16 Oct 2017 (v1), 13 Jun 2018 (v3)

Susanna Kohler wrote:
What happens to planets orbiting around stars that age past the main sequence and evolve into red giants? These enormous reddened stars — our Sun’s fate billions of years from now — may have significant impacts on the planet populations around them. A new study explores these impacts by looking at the orbits of gas giants closely circling evolved stars. ...

• Astrophysical Journal Letters 861(1):L5 (2018 Jul 01) DOI: 10.3847/2041-8213/aacc67
  arXiv.org > astro-ph > arXiv:1805.11620 > 29 May 2018 (v1), 08 Jul 2018 (v2)

Susanna Kohler wrote:
Sometimes more-precise measurements are all we need to make new discoveries in old structures! In a new study, data from the Gaia mission has revealed a surprise hidden among main-sequence stars. ...

• Astrophysical Journal Letters 861(1):L11 (2018 Jul 01) DOI: 10.3847/2041-8213/aacdf6
  arXiv.org > astro-ph > arXiv:1806.07792 > 20 Jun 2018

Kerry Hensley wrote:
The high-energy catalogs of the Fermi Large Area Telescope contain more than a thousand gamma-ray detections that have never been connected to a source. Some of these gamma rays could stem from very exotic objects: bow shocks of runaway stars. ...

• Astrophysical Journal 861(1):32 (2018 Jul 01) DOI: 10.3847/1538-4357/aac7c7
  arXiv.org > astro-ph > arXiv:1806.00614 > 02 Jun 2018

Susanna Kohler wrote:
An X-ray telescope recently installed on the International Space Station has been improving our view of distant high-energy sources, one object at a time. Now, this telescope has provided a detailed look at a black hole feeding off its companion star. ...

• Astrophysical Journal Letters 860(2):L28 (2018 Jun 20) DOI: 10.3847/2041-8213/aacc61
  arXiv.org > astro-ph > arXiv:1806.04115 > 11 Jun 2018

Susanna Kohler wrote:
At some point in a galaxy’s life, it transitions from a star-forming factory into an old, red, inactive relic. Can new observations of a recently transitioned galaxy help us understand what drives that change? ...

• Astrophysical Journal Letters 860(2):L18 (2018 Jun 20) DOI: 10.3847/2041-8213/aaca9a
  arXiv.org > astro-ph > arXiv:1804.10216 > 26 Apr 2018

Susanna Kohler wrote:
Finding planets around ordinary stars is great, but what if we could also hunt for planets around the black holes, neutron stars, and white dwarfs that live in binaries with companion stars? A new study shows it’s possible! ...

• Astrophysical Journal 859(1):40 (2018 May 20) DOI: 10.3847/1538-4357/aab903
  arXiv.org > astro-ph > arXiv:1703.05762 > 16 Mar 2017 (v1), 24 Apr 2018 (v2)

Susanna Kohler wrote:
Despite the Sun’s proximity, there’s still a lot we don’t know about our nearest star! A new study, however, has brought us a step closer to understanding one of its mysteries: how the solar atmosphere is heated. ...

• Astrophysical Journal 860(2):99 (20 Jun 2018) DOI: 10.3847/1538-4357/aac0f8

Kerry Hensley wrote:
What’s going on in the galactic bulge? The discovery of the double red clump — two groupings of stars seen in the color-magnitude diagram of the galactic bulge — has raised questions about the structure and formation history of the stars surrounding the center of our galaxy. ...

• Astrophysical Journal Letters 862(1):L8 (2018 Jul 20) DOI: 10.3847/2041-8213/aad192
  arXiv.org > astro-ph > arXiv:1807.00004 > 29 Jun 2018

Susanna Kohler wrote:
How can stellar-mass black holes attain the large sizes we’ve recently observed in merging binaries? A recent study explores an intriguing possibility: perhaps these smaller black holes grow and collide while trapped within the accretion disks that can surround enormous supermassive black holes. ...

• Astrophysical Journal Letters 859(2):L25 (2018 Jun 01) DOI: 10.3847/2041-8213/aac649
  arXiv.org > astro-ph > arXiv:1805.07026 > 18 May 2018

Susanna Kohler wrote:
Solar flares, coronal mass ejections, prominences, sunspots — the most exciting features of the Sun are all driven by complex magnetic activity within the Sun’s interior and at its surface. Indeed, observations of the Sun have long revealed regions of magnetic flux of various magnitudes and polarities across the Sun’s disk.

But it wasn’t until 1970 that scientists started measuring a different aspect of the Sun’s magnetization: its mean magnetic field. By treating the Sun like a distant star and measuring its net magnetic field by integrating across its whole disk, scientists have been able to effectively measure the imbalance in the magnetic flux of opposite polarities across its visible disk. A new study explores what might create this overall imbalance. ...

• Astrophysical Journal 862(1):35 (2018 Jul 20) DOI: 10.3847/1538-4357/aaccf1
  arXiv.org > astro-ph > arXiv:1806.05291 > 13 Jun 2018

Susanna Kohler wrote:
The mysterious object Segue 1 has intrigued astronomers since it was first discovered in 2007. A new study has now measured the first proper motions for this tiny neighboring galaxy, providing clues as to how it came to be in orbit around the Milky Way. ...

• Astrophysical Journal 860(2):164 (20 Jun 2018) DOI: 10.3847/1538-4357/aac516
  arXiv.org > astro-ph > arXiv:1711.09097 > 24 Nov 2017 (v1), 21 May 2018 (v3)

Kerry Hensley wrote:
Over billions of years, globular clusters and dwarf galaxies orbiting the Milky Way have been torn apart and stretched out by tidal forces. The disruption of these ancient stellar populations results in narrow trails of stars called stellar streams. These stellar streams can help us understand how the Milky Way halo was constructed and what our galaxy’s dark matter distribution is like — but how do we find them? ...

• Astrophysical Journal 862(2):114 (2018 Aug 01) DOI: 10.3847/1538-4357/aacdab
  arXiv.org > astro-ph > arXiv:1801.03097 > 09 Jan 2018

Susanna Kohler wrote:
How do we find extraterrestrial intelligence (ETI) — not just life beyond Earth, but advanced extraterrestrial civilizations? One approach is to seek signals from ETI that may be attempting to communicate with us — but the problem of where, when, and how to look for such communications is a complex one. A new study explores one way we could optimize this hunt: by searching for communication signals that are synchronized with the merger of two neutron stars. ...

• Astrophysical Journal Letters 862(2):L21 (2018 Aug 01) DOI: 10.3847/2041-8213/aad33d
  arXiv.org > astro-ph > arXiv:1807.06024 > 16 Jul 2018

Susanna Kohler wrote:
The Sun is a rather well-studied star, so it’s always exciting when we get the opportunity to observe it in a new way. One such opportunity is upcoming, via the Parker Solar Probe that just launched last week. But while we wait for that new view of the Sun, we have another one to examine: the Sun in microwaves. ...

• Astrophysical Journal 863(1):83 (10 Aug 2018) DOI: 10.3847/1538-4357/aad0ef
  arXiv.org > astro-ph > arXiv:1807.02498 > 06 Jul 2018

Susanna Kohler wrote:
The gas giant PDS 70b made headlines last month as the first newly forming planet to ever be directly imaged. Now a team of scientists has gone a step further: they’ve captured evidence that this planet is actively accreting material, and they’ve measured the rate at which it’s growing. ...

• Astrophysical Journal Letters 863(1):L8 (2018 Aug 10) DOI: 10.3847/2041-8213/aad695
  arXiv.org > astro-ph > arXiv:1807.10766 > 27 Jul 2018

Kerry Hensley wrote:
The gravity of massive galaxies can warp the light from distant background sources into dramatic shapes. Gravitational lensing by foreground stars, planets, and other low-mass objects may be less visually stunning, but these tiny lensing events hold big promise. ...

• Astrophysical Journal 863(1):23 (2018 Aug 10) DOI: 10.3847/1538-4357/aacdf4
  arXiv.org > astro-ph > arXiv:1801.00169 > 30 Dec 2017 (v1), 19 Jun 2018 (v2)

Susanna Kohler wrote:
One of the primary goals of exoplanet-hunting missions like Kepler is to discover Earth-like planets in their hosts’ habitable zones. But could there be other relevant worlds to look for? A new study has explored the possibility of habitable moons around giant planets. ...

• Astrophysical Journal 860(1):67 (2018 Jun 10) DOI: 10.3847/1538-4357/aac384
  arXiv.org > astro-ph > arXiv:1805.03370 > 09 May 2018

Kerry Hensley wrote:
The advent of gravitational-wave astrophysics has made possible the study of elusive cosmic phenomena — like the mysterious merging of stellar-mass black holes. ...

• Astrophysical Journal Letters 863(2):L41 (2018 Aug 20) DOI: 10.3847/2041-8213/aad800
  arXiv.org > astro-ph > arXiv:1805.10270 > 25 May 2018 (v1), 22 Aug 2018 (v2)

Susanna Kohler wrote:
Much of today’s astronomy happens via methodical searches, but sometimes serendipitous discoveries still surprise us. Such is the case with the transient CGS2004A, a possible supernova recently detected in a galaxy nearly 50 million light-years away. ...

• Research Notes of the AAS 2(3):165 (July 2018) DOI: 10.3847/2515-5172/aade89
  arXiv.org > astro-ph > arXiv:1809.00163 > 01 Sep 2018

Susanna Kohler wrote:
A supermassive black hole lurks at the center of our galaxy — and we’re still trying to understand its structure and behavior. Now scientists have made new detections of Sgr A* in far infrared, helping us to further piece together a picture of this monster. ...

• Astrophysical Journal 862(2):129 (2018 Aug 01) DOI: 10.3847/1538-4357/aacd4b
  arXiv.org > astro-ph > arXiv:1806.07395 > 19 Jun 2018

Susanna Kohler wrote:
One of the greatest misconceptions about astronomy as a profession is that we all sit alone in front of a telescope eyepiece every night, gazing at the stars. In reality, today’s observational astronomy is collaborative — and it takes the form of ones and zeros on a computer. ...

• Astronomical Journal 156(3):123 (Sep 2018) DOI: 10.3847/1538-3881/aabc4f
  arXiv.org > astro-ph > arXiv:1801.02634 > 08 Jan 2018 (v1), 16 Jan 2018 (v2)