AAS NOVA — Research Highlights 2019

bystander · Post by **bystander** » Sun Oct 13, 2019 3:12 pm

Possibly Impossible Planets
NOVA | American Astronomical Society | 2019 Oct 11

Tarini Konchady wrote:
Knowing which planets can form will help us understand how planets form. So as we discover more and more exoplanets, one must wonder: what if there are certain types of planets that just don’t exist? ...

A Gap in the Mass Distribution for Warm Neptune and Terrestrial Planets ~ David J. Armstrong et al

Astrophysical Journal Letters 880(1):L1 (2019 Jul 20) DOI: 10.3847/2041-8213/ab2ba2
arXiv.org > astro-ph > arXiv:1906.11865 > 27 Jun 2019

bystander · Post by **bystander** » Thu Oct 24, 2019 3:20 pm

Tracking Gas in Star-Forming Galaxies
NOVA | American Astronomical Society | 2019 Oct 14

Susanna Kohler wrote:
How has galaxy evolution changed over our universe’s history? To understand this, we need to track galaxies’ stars and gas over time. Stars are relatively easy: they’re bright and can be observed with deep optical and infrared observations. But gas? That’s a little trickier. ...

Atomic Hydrogen in Star-forming Galaxies at Intermediate Redshifts ~ Apurba Bera et al

Astrophysical Journal Letters 882(1):L7 (2019 Sep 01) DOI: 10.3847/2041-8213/ab3656
arXiv.org > astro-ph > arXiv:1909.05905 > 12 Sep 2019

bystander · Post by **bystander** » Thu Oct 24, 2019 3:25 pm

The Big Picture of Solar Flares
NOVA | American Astronomical Society | 2019 Oct 16

Susanna Kohler wrote:
Bright eruptions from the Sun’s surface can influence everything from the Sun’s own atmosphere to the Earth and beyond. The good news: we’ve got decades of detailed observations of solar flares available for study. The bad news: we may be interpreting these data incorrectly. ...

Solar Flare Distributions: Lognormal Instead of Power Law? ~ Cis Verbeeck et al

Astrophysical Journal 884(1):50 (2019 Oct 10) DOI: 10.3847/1538-4357/ab3425

bystander · Post by **bystander** » Thu Oct 24, 2019 3:34 pm

Snowball Events for Tidally Locked Planets?
NOVA | American Astronomical Society | 2019 Oct 23

Susanna Kohler wrote:
The Earth likely underwent several periods of planet-wide ice coverage in the past, in what’s known as snowball Earth events. A new study explores whether snowball events are also a risk for tidally locked, habitable exoplanets. ...

No Snowball on Habitable Tidally Locked Planets with a Dynamic Ocean ~ Jade H. Checlair et al

Astrophysical Journal Letters 884(2):L46 (2019 Oct 20) DOI: 10.3847/2041-8213/ab487d
arXiv.org > astro-ph > arXiv:1910.06285 > 14 Oct 2019

bystander · Post by **bystander** » Sat Oct 26, 2019 5:20 am

When Neutron Stars Merge
NOVA | American Astronomical Society | 2019 Oct 25

Tarini Konchady wrote:
To predict how often binary neutron star mergers occur, we need to know when binary neutron stars are born and how long it takes them to merge. An avenue for understanding this is to carefully study their host galaxies. ...

Measuring the Delay Time Distribution of Binary Neutron Stars. III.
Using the Individual Star Formation Histories of Gravitational-Wave
Event Host Galaxies in the Local Universe ~ Mohammadtaher Safarzadeh et al

Astrophysical Journal Letters 878(1):L14 (2019 Jun 10) DOI: 10.3847/2041-8213/ab24e3
arXiv.org > astro-ph > arXiv:1905.04310 > 10 May 2019 (v1), 28 May 2019 (v2)

bystander · Post by **bystander** » Fri Nov 01, 2019 3:21 pm

Life on the Red Edge
NOVA | American Astronomical Society | 2019 Oct 28

Tarini Konchady wrote:
How can we identify life on other planets? The Earth might be able to help with that — specifically with something called the red edge. ...

Expanding the Timeline for Earth’s Photosynthetic Red Edge Biosignature ~ Jack T. O'Malley-James, Lisa Kaltenegger

Astrophysical Journal Letters 879(2):L20 (2019 Jul 10) DOI: 10.3847/2041-8213/ab2769
arXiv.org > astro-ph > arXiv:1907.05245 > 10 Jul 2019

bystander · Post by **bystander** » Thu Nov 07, 2019 5:18 pm

Lessons from a Quartet of Newborn Planets
NOVA | American Astronomical Society | 2019 Nov 06

Susanna Kohler wrote:
Though we’ve discovered thousands of planets beyond our solar system, we still have a lot to learn about how these bodies form and evolve. Now, a newly discovered baby planetary system may provide some insight. ...

Four Newborn Planets Transiting the Young Solar Analog V1298 Tau ~ Trevor J. David et al

Astrophysical Journal Letters 885(1):L12 (2019 Nov 01) DOI: 10.3847/2041-8213/ab4c99
arXiv.org > astro-ph > arXiv:1910.04563 > 10 Oct 2019

bystander · Post by **bystander** » Mon Nov 11, 2019 8:00 pm

A Standard of Black Hole Mergers
NOVA | American Astronomical Society | 2019 Nov 08

Tarini Konchady wrote:
Being able to make precise measurements of distances and redshifts will help us understand how the universe is evolving. With the advent of gravitational wave observatories, we can make these measurements by using black holes in a very different way than before. ...

A Future Percent-Level Measurement of the Hubble Expansion
at Redshift 0.8 with Advanced LIGO ~ Will M. Farr et al

Astrophysical Journal Letters 883(2):L42 (2019 Oct 01) DOI: 10.3847/2041-8213/ab4284
arXiv.org > astro-ph > arXiv:1908.09084 > 24 Aug 2019 (v1), 06 Sep 2019 (v2)

bystander · Post by **bystander** » Mon Nov 11, 2019 8:09 pm

A New Measurement of Turbulence
NOVA | American Astronomical Society | 2019 Nov 11

Susanna Kohler wrote:
The same physical phenomenon that causes bumpy airplane rides also pervades our universe, jumbling stellar atmospheres, interstellar clouds, and even the magnetized sheath surrounding the Earth. Now, a new study brings us a little closer to understanding turbulence. ...

Direct Measurement of the Dissipation Rate Spectrum around Ion Kinetic Scales in Space Plasma Turbulence ~ Jiansen He et al

Astrophysical Journal 880(2):121 (2019 Aug 01) DOI: 10.3847/1538-4357/ab2a79

bystander · Post by **bystander** » Sat Nov 16, 2019 3:21 pm

Hunting for a Dark Matter Wake
NOVA | American Astronomical Society | 2019 Nov 13

Susanna Kohler wrote:
As the Large Magellanic Cloud plows through the Milky Way’s dark matter halo, it may leave telltale signs of its passage. A recent study explores whether we’ll be able to spot this evidence — and what it can tell us about our galaxy and the nature of dark matter. ...

Hunting for the Dark Matter Wake Induced by the Large Magellanic Cloud ~ Nicolas Garavito-Camargo et al

Astrophysical Journal 884(1):51 (2019 Oct 10) DOI: 10.3847/1538-4357/ab32eb
arXiv.org > astro-ph > arXiv:1902.05089 > 13 Feb 2019 (v1), 11 Sep 2019 (v2)

bystander · Post by **bystander** » Sat Nov 16, 2019 3:25 pm

Smashing Planets to Build Giants
NOVA | American Astronomical Society | 2019 Nov 15

Susanna Kohler wrote:
How do you get close-in, giant planets on eccentric orbits? A new study suggests that a violent phase of planet-smashing might be a key part of the process. ...

Signatures of a Planet–Planet Impacts Phase in Exoplanetary Systems Hosting Giant Planets ~ Renata Frelikh et al

Astrophysical Journal Letters 884(2):L47 (2019 Oct 20) DOI: 10.3847/2041-8213/ab4a7b
arXiv.org > astro-ph > arXiv:1906.03266 > 07 Jun 2019 (v1), 08 Oct 2019 (v2)

viewtopic.php?t=39955

bystander · Post by **bystander** » Sat Nov 23, 2019 4:13 pm

Where’s the (Magnetic) Flux?
NOVA | American Astronomical Society | 2019 Nov 20

Susanna Kohler wrote:
General models of the Sun’s atmosphere have a fundamental problem: the magnetic flux they predict here at Earth is much lower than what we actually observe. Has a new study found the missing flux? ...

Can an Unobserved Concentration of Magnetic Flux Above
the Poles of the Sun Resolve the Open Flux Problem? ~ Pete Riley et al

Astrophysical Journal 884(1):18 (2019 Oct 10) DOI: 10.3847/1538-4357/ab3a98

bystander · Post by **bystander** » Sat Nov 23, 2019 4:20 pm

Fantastically Fast Transients and How They Happen
NOVA | American Astronomical Society | 2019 Nov 22

Tarini Konchady wrote:
A supernova-like transient was observed to decline stupendously fast. What could have caused it? ...

SN2018kzr: A Rapidly Declining Transient from the Destruction of a White Dwarf ~ Owen R. McBrien et al

Astrophysical Journal Letters 885(1):L23 (2019 Nov 01) DOI: 10.3847/2041-8213/ab4dae
arXiv.org > astro-ph > arXiv:1909.04545 > 10 Sep 2019 (v1), 19 Nov 2019 (v2)

bystander · Post by **bystander** » Thu Nov 28, 2019 1:46 am

The Appearance of a Black Hole’s Shadow
NOVA | American Astronomical Society | 2019 Nov 25

Susanna Kohler wrote:
In April of this year, the Event Horizon Telescope captured the first detailed images of the shadow of a black hole. In a new study, a team of scientists has now explored what determines the size and shape of black hole shadows like this one. ...

The Shadow of a Spherically Accreting Black Hole ~ Ramesh Narayan, Michael D. Johnson, Charles F. Gammie

Astrophysical Journal Letters 885(2):L33 (2019 Nov 10) DOI: 10.3847/2041-8213/ab518c
arXiv.org > astro-ph > arXiv:1910.02957 > 07 Oct 2019 (v1), 25 Oct 2019 (v2)

viewtopic.php?t=39338

bystander · Post by **bystander** » Thu Nov 28, 2019 1:52 am

Climates of Distant Terrestrial Worlds
NOVA | American Astronomical Society | 2019 Nov 27

Susanna Kohler wrote:
What determines the climate of an Earth-like planet orbiting its host star? And how is that climate affected by the type of star the planet orbits? A new study explores how distant terrestrial worlds are shaped by their hosts. ...

Energy Budgets for Terrestrial Extrasolar Planets ~ Aomawa L. Shields, Cecilia M. Bitz, Igor Palubski

Astrophysical Journal Letters 884(1):L2 (2019 Oct 10) DOI: 10.3847/2041-8213/ab44ce
arXiv.org > astro-ph > arXiv:1909.07418 > 16 Sep 2019

bystander · Post by **bystander** » Tue Dec 10, 2019 4:44 pm

When A Black Hole (Partially) Destroys a Star
NOVA | American Astronomical Society | 2019 Dec 03

Susanna Kohler wrote:
Close encounters between stars and supermassive black holes generally don’t end well for the stars. Under the influence of a black hole’s strong gravitational forces, an unsuspecting passing star can be completely shredded, resulting in a spectacular tidal disruption flare. But what happens when the star is only partially destroyed? ...

Partial Stellar Disruption by a Supermassive Black Hole:
Is the Lightcurve Really Proportional to t^−9/4? ~ Eric R. Coughlin, C. J. Nixon

Astrophysical Journal Letters 883(1):L17 (2019 Sep 20) DOI: 10.3847/2041-8213/ab412d
arXiv.org > astro-ph > arXiv:1907.03034 > 05 Jul 2019 (v1), 04 Sep 2019 (v2)

bystander · Post by **bystander** » Tue Dec 10, 2019 4:50 pm

Mass-ive Implications for Exoplanetary Atmospheres
NOVA | American Astronomical Society | 2019 Dec 09

Tarini Konchady wrote:
One of the goals of the Transiting Exoplanet Survey Satellite (TESS) is to identify exoplanets whose atmospheres can be characterized by other telescopes. Part of this process entails measuring planetary masses to some degree of precision. So just how well do we need to know an exoplanet’s mass to understand its atmosphere? ...

The Precision of Mass Measurements Required for Robust Atmospheric
Characterization of Transiting Exoplanets ~ Natasha E. Batalha et al

Astrophysical Journal Letters 885(1):L25 (2019 Nov 01) DOI: 10.3847/2041-8213/ab4909
arXiv.org > astro-ph > arXiv:1910.00076 > 2019 Sep 30

Ann · Post by **Ann** » Fri Dec 13, 2019 6:56 am

bystander wrote: ↑Thu Nov 28, 2019 1:52 am Climates of Distant Terrestrial Worlds
NOVA | American Astronomical Society | 2019 Nov 27
Susanna Kohler wrote:
What determines the climate of an Earth-like planet orbiting its host star? And how is that climate affected by the type of star the planet orbits? A new study explores how distant terrestrial worlds are shaped by their hosts. ...

Energy Budgets for Terrestrial Extrasolar Planets ~ Aomawa L. Shields, Cecilia M. Bitz, Igor Palubski
Astrophysical Journal Letters 884(1):L2 (2019 Oct 10) DOI: 10.3847/2041-8213/ab44ce

arXiv.org > astro-ph > arXiv:1909.07418 > 16 Sep 2019

Sometimes I feel endlessly stupid when I face what to me seems to be counter-intuitive claims from astronomers.

Susanna Kohler of aasnova.org wrote:

For an M-dwarf host, a tidally locked planet has lower minimum and maximum dayside temperatures when compared with a planet with a 24-hour rotation period; the average dayside temperature is around 37 K colder on the tidally locked planet.

So the permanently sun-facing side of a tidally locked planet would be colder than the dayside of a planet with a 24-hour rotation period? And what about the permanent nightside of a tidally locked planet, would that be milder than than the nightside of a planet with a 24-hour rotation period? How can this be possible?

Ann

Chris Peterson · Post by **Chris Peterson** » Fri Dec 13, 2019 2:31 pm

Ann wrote: ↑Fri Dec 13, 2019 6:56 am
bystander wrote: ↑Thu Nov 28, 2019 1:52 am Climates of Distant Terrestrial Worlds
NOVA | American Astronomical Society | 2019 Nov 27
Susanna Kohler wrote:
What determines the climate of an Earth-like planet orbiting its host star? And how is that climate affected by the type of star the planet orbits? A new study explores how distant terrestrial worlds are shaped by their hosts. ...

Energy Budgets for Terrestrial Extrasolar Planets ~ Aomawa L. Shields, Cecilia M. Bitz, Igor Palubski
Astrophysical Journal Letters 884(1):L2 (2019 Oct 10) DOI: 10.3847/2041-8213/ab44ce

arXiv.org > astro-ph > arXiv:1909.07418 > 16 Sep 2019

Sometimes I feel endlessly stupid when I face what to me seems to be counter-intuitive claims from astronomers.

Susanna Kohler of aasnova.org wrote:

For an M-dwarf host, a tidally locked planet has lower minimum and maximum dayside temperatures when compared with a planet with a 24-hour rotation period; the average dayside temperature is around 37 K colder on the tidally locked planet.
So the permanently sun-facing side of a tidally locked planet would be colder than the dayside of a planet with a 24-hour rotation period? And what about the permanent nightside of a tidally locked planet, would that be milder than than the nightside of a planet with a 24-hour rotation period? How can this be possible?

Ann

Consider that one consequence of global warming is colder mid-latitude winters (at least in the northern hemisphere). Climate reflects the output of a huge, complex heat engine. You put energy in, and it moves around. Put more energy in, it moves differently. It's not as simple as the temperature is defined by the amount of sunlight some particular square meter receives. How many times do you remember having a cold day followed by a warm night? It's a common thing.

I didn't read the linked paper, but it's easy enough for me to imagine that a tidally locked planet might have very high global winds that serve to equalize the overall atmospheric temperature more than a rotating planet might.

bystander · Post by **bystander** » Tue Dec 17, 2019 8:36 pm

An Extreme Pulsar Seen in Gamma Rays
NOVA | American Astronomical Society | 2019 Dec 11

Susanna Kohler wrote:
One of the fastest spinning radio pulsars known has now been detected to pulse in gamma rays, too. What can we learn about this extreme pulsar from new observations? ...

Detection and Timing of Gamma-Ray Pulsations from the 707 Hz Pulsar J0952−0607 ~ L. Nieder et al

Astrophysical Journal 883(1):42 (2019 Sep 20) DOI: 10.3847/1538-4357/ab357e
arXiv.org > astro-ph > arXiv:1905.11352 > 27 May 2019 (v1), 19 Sep 2019 (v2)

viewtopic.php?t=39816

bystander · Post by **bystander** » Tue Dec 17, 2019 9:12 pm

Neutrinos and Gravitational Waves from Cosmic Catastrophes
NOVA | American Astronomical Society | 2019 Dec 16

Susanna Kohler wrote:
No significant detections of high-energy neutrinos and gravitational waves coming from the same astrophysical source were found during the Laser Interferometer Gravitational-Wave Observatory’s (LIGO’s) first observing run. This was established from detailed analysis and comparison of IceCube and Antares neutrino candidates and LIGO gravitational-wave candidates over the ~130-day observing period. ...

Search for Multimessenger Sources of Gravitational Waves and High-energy Neutrinos with Advanced LIGO during
Its First Observing Run, ANTARES, and IceCube ~ ANTARES, IceCube, LIGO, Virgo Collaborations: A. Albert et al

Astrophysical Journal 870(2):134 (2019 Jan 10) DOI: 10.3847/1538-4357/aaf21d
arXiv.org > astro-ph > arXiv:1810.10693 > 25 Oct 2018 (v1), 15 Nov 2018 (v2)

bystander · Post by **bystander** » Tue Dec 17, 2019 9:17 pm

A Giant Planet Around an Evolved Binary
NOVA | American Astronomical Society | 2019 Dec 17

Susanna Kohler wrote:
In a study led by Leonardo Almeida (Federal University of Rio Grande do Norte and University of São Paulo, Brazil), scientists announce evidence for a 13-Jupiter-mass planet around an evolved binary system, KIC 10544976, that consists of a white dwarf and a red dwarf star orbiting each other once every 0.35 days. ...

Orbital Period Variation of KIC 10544976: Applegate Mechanism
versus Light Travel Time Effect ~ Leonardo A. Almeida et al

Astronomical Journal 157(4):150 (Apr 2019) DOI: 10.3847/1538-3881/ab0963
arXiv.org > astro-ph > arXiv:1903.09637 > 20 Mar 2019

viewtopic.php?t=39340

bystander · Post by **bystander** » Fri Dec 20, 2019 8:44 pm

Explanation for an Interstellar Visitor
NOVA | American Astronomical Society | 2019 Dec 18

Susanna Kohler wrote:
Remember the first known interstellar asteroid, 1I/’Oumuamua? A study by scientist Marshall Eubanks (Space Initiatives, Inc.) explores the possibility that the asteroid is a very lightweight, high-drag object that long ago orbited the galaxy, became caught up within dense interstellar gas, and was then released in our direction as part of the Pleiades dynamical stream. ...

High-Drag Interstellar Objects and Galactic Dynamical Streams ~ T. M. Eubanks

Astrophysical Journal Letters 874(2):L11 (2019 Apr 01) DOI: 10.3847/2041-8213/ab0f29
arXiv.org > astro-ph > arXiv:1903.09496 > 20 Mar 2019

bystander · Post by **bystander** » Fri Dec 20, 2019 8:50 pm

Rethinking Carbon Monoxide in the Search for Life
NOVA | American Astronomical Society | 2019 Dec 19

Susanna Kohler wrote:
A team of scientists led by Edward Schwieterman (UC Riverside) used computer simulations of planetary ecospheres/atmospheres to show that a number of planet types of interest in the search for life — like planets similar to early Earth, or planets around M-dwarf stars — can maintain an accumulation of carbon monoxide in their atmospheres. ...

Rethinking CO Antibiosignatures in the Search for Life Beyond the Solar System ~ Edward W. Schwieterman et al

Astrophysical Journal 874(1):9 (2019 Mar 20) DOI: 10.3847/1538-4357/ab05e1
arXiv.org > astro-ph > arXiv:1903.07661 > 18 Mar 2019

bystander · Post by **bystander** » Fri Dec 20, 2019 8:55 pm

An Average Quasar at an Above-Average Distance
NOVA | American Astronomical Society | 2019 Dec 20

Susanna Kohler wrote:
A team of scientists led by Yoshiki Matsuoka (Ehime University, Japan) announced the discovery of the first low-luminosity quasar — a dim supermassive black hole actively feeding at the center of a galaxy — found at a redshift of z > 7. This redshift represents a time when the universe was still in its infancy, at less than a billion years old. ...

Discovery of the First Low-Luminosity Quasar at z > 7 ~ Yoshiki Matsuoka et al

Astrophysical Journal Letters 872(1):L2 (2019 Feb 10) DOI: 10.3847/2041-8213/ab0216
arXiv.org > astro-ph > arXiv:1901.10487 > 29 Jan 2019

viewtopic.php?t=39264

Starship Asterisk*

AAS NOVA — Research Highlights 2019

Possibly Impossible Planets

Tracking Gas in Star-Forming Galaxies

The Big Picture of Solar Flares

Snowball Events for Tidally Locked Planets?

When Neutron Stars Merge

Life on the Red Edge

Lessons from a Quartet of Newborn Planets

A Standard of Black Hole Mergers

A New Measurement of Turbulence

Hunting for a Dark Matter Wake

Smashing Planets to Build Giants

Where’s the (Magnetic) Flux?

Fantastically Fast Transients and How They Happen

The Appearance of a Black Hole’s Shadow

Climates of Distant Terrestrial Worlds

When A Black Hole (Partially) Destroys a Star

Mass-ive Implications for Exoplanetary Atmospheres

Re: Climates of Distant Terrestrial Worlds

Re: Climates of Distant Terrestrial Worlds

An Extreme Pulsar Seen in Gamma Rays

Neutrinos and Gravitational Waves from Cosmic Catastrophes

A Giant Planet Around an Evolved Binary

Explanation for an Interstellar Visitor

Rethinking Carbon Monoxide in the Search for Life

An Average Quasar at an Above-Average Distance