Author Topic: Astronomy & Planetary Science Thread  (Read 442063 times)

Offline Star One

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Re: Astronomy Thread
« Reply #340 on: 02/22/2018 08:47 am »
An amateur astronomer accidentally caught an exploding star on camera—and it gets better

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Victor Buso was looking forward to testing his new camera on September 20, 2016. The locksmith and amateur astronomer waited for nightfall and headed out to his rooftop observatory in the city of Rosario, Argentina, where his 15.7 inch (40 cm) Newtonian telescope was waiting. He had no idea he would help capture the start of one of the most unpredictable events in the universe; a supernova.

https://www.popsci.com/amateur-astronomer-photographs-birth-supernova

Offline IRobot

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Re: Astronomy Thread
« Reply #341 on: 02/22/2018 10:33 am »
An amateur astronomer accidentally caught an exploding star on camera—and it gets better

Having worked for several years in the "amateur" astronomy market making CCD cameras, I find it harder and harder to call these people "amateurs". Especially one like this, owning a 16inch scope.
They spend tens of thousands of dollars, sometimes hundreds of thousands of dollars and they make some remarkable things, considering that they are not working full time, most of them don't have the technical or theoretical background and they work most of the times from sub urban locations.

I even know some who do yearly calibrations of professional telescopes!

Among several achievements, they have done:
- discoveries of supernovas
- discoveries of exoplanets
- discoveries of nebulae or nebulae sub-structures
- rocket launch and satellite tracking
- long lost IMAGE sattelite
- independent confirmations of known phenomenons

The last point is important. One argument against conspiracy theories (flat earth, moon landing deniers, UFOs,...) is that amateur astronomers, being independent, keep disproving these wacky theories.

Offline Star One

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Re: Astronomy Thread
« Reply #342 on: 02/22/2018 07:36 pm »
Studying the Ultraviolet Spectrum of the First Spectroscopically Confirmed Supernova at Redshift Two

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Abstract
We present observations of DES16C2nm, the first spectroscopically confirmed hydrogen-free superluminous supernova (SLSN-I) at redshift $z\approx 2$. DES16C2nm was discovered by the Dark Energy Survey (DES) Supernova Program, with follow-up photometric data from the Hubble Space Telescope, Gemini, and the European Southern Observatory Very Large Telescope supplementing the DES data. Spectroscopic observations confirm DES16C2nm to be at z = 1.998, and spectroscopically similar to Gaia16apd (a SLSN-I at z = 0.102), with a peak absolute magnitude of $U=-22.26\pm 0.06$. The high redshift of DES16C2nm provides a unique opportunity to study the ultraviolet (UV) properties of SLSNe-I. Combining DES16C2nm with 10 similar events from the literature, we show that there exists a homogeneous class of SLSNe-I in the UV (${\lambda }_{\mathrm{rest}}\approx 2500$ Å), with peak luminosities in the (rest-frame) U band, and increasing absorption to shorter wavelengths. There is no evidence that the mean photometric and spectroscopic properties of SLSNe-I differ between low ($z\lt 1$) and high redshift ($z\gt 1$), but there is clear evidence of diversity in the spectrum at ${\lambda }_{\mathrm{rest}}\lt 2000\,\mathring{\rm A} $, possibly caused by the variations in temperature between events. No significant correlations are observed between spectral line velocities and photometric luminosity. Using these data, we estimate that SLSNe-I can be discovered to z = 3.8 by DES. While SLSNe-I are typically identified from their blue observed colors at low redshift ($z\lt 1$), we highlight that at $z\gt 2$ these events appear optically red, peaking in the observer-frame z-band. Such characteristics are critical to identify these objects with future facilities such as the Large Synoptic Survey Telescope, Euclid, and the Wide-field Infrared Survey Telescope, which should detect such SLSNe-I to z = 3.5, 3.7, and 6.6, respectively.

http://iopscience.iop.org/article/10.3847/1538-4357/aaa126/meta

Offline Star One

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Re: Astronomy Thread
« Reply #343 on: 02/22/2018 08:23 pm »
Some black holes erase your past

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In the real world, your past uniquely determines your future. If a physicist knows how the universe starts out, she can calculate its future for all time and all space.

But a UC Berkeley mathematician has found some types of black holes in which this law breaks down. If someone were to venture into one of these relatively benign black holes, they could survive, but their past would be obliterated and they could have an infinite number of possible futures.

http://news.berkeley.edu/2018/02/20/some-black-holes-erase-your-past/

Offline eeergo

Re: Astronomy Thread
« Reply #344 on: 02/24/2018 12:14 pm »
https://www.nature.com/articles/nature25151


An "amateur" Argentinian astronomer from Rosario has observed, for the first time, the start of a supernova (IIb) explosion, confirming theoretical models.


http://www.agenciasinc.es/Multimedia/Fotografias/Un-astronomo-aficionado-capta-una-supernova-en-directo (in Spanish)
-DaviD-

Offline Star One

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Re: Astronomy Thread
« Reply #345 on: 02/25/2018 08:21 am »
https://www.nature.com/articles/nature25151


An "amateur" Argentinian astronomer from Rosario has observed, for the first time, the start of a supernova (IIb) explosion, confirming theoretical models.


http://www.agenciasinc.es/Multimedia/Fotografias/Un-astronomo-aficionado-capta-una-supernova-en-directo (in Spanish)

See post #341 in this thread.

Offline missinglink

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Re: Astronomy Thread
« Reply #346 on: 02/26/2018 08:33 am »
Formation of the Earth's inner core is so baffling, scientists say it shouldn't exist

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According to the popular view of the Earth's formation, about one billion years ago, our planet's molten liquid inner core spontaneously began to crystallise, growing rapidly to the extent that it reaches today – around 760 miles in diameter.

However, a new study published in the journal Earth and Planetary Science Letters contradicts this theory, suggesting it is impossible.

http://www.ibtimes.co.uk/formation-earths-inner-core-so-baffling-scientists-say-it-shouldnt-exist-1661119
Only one way to settle this once and for all ... a giant power drill made of pure diamond to carry a determined crew into the beating heart of the planet ... and back out again on the other side.

Offline Star One

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Astronomy Thread
« Reply #347 on: 02/27/2018 08:13 pm »
These results seemingly confirm that the expansion of the universe has accelerated since its early days.

Precise New Measurements From Hubble Confirm the Accelerating Expansion of the Universe. Still no Idea Why it’s Happening

https://www.universetoday.com/138663/precise-new-measurements-hubble-confirm-accelerating-expansion-universe-still-no-idea-happening/amp/

Beaming with the Light of Millions of Suns

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In the 1980s, researchers began discovering extremely bright sources of X-rays in the outer portions of galaxies, away from the supermassive black holes that dominate their centers. At first, the researchers thought these cosmic objects—called ultraluminous X-ray sources, or ULXs—were hefty black holes with more than 10 times the mass of the sun. But observations beginning in 2014 from NASA's NuSTAR (Nuclear Spectroscopic Telescope Array) and other space telescopes are showing that some ULXs, which glow with X-ray light equal in energy to millions of suns, are actually neutron stars—the burnt-out cores of massive stars that exploded. Three such ULXs have been identified as neutron stars so far.

http://m.caltech.edu/news/beaming-light-millions-suns-81447

When do aging brown dwarfs sweep the clouds away?

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Astronomers measure temperature at which brown dwarfs go from cloudy to cloudless

https://www.eurekalert.org/pub_releases/2018-02/cifs-wda022618.php
« Last Edit: 02/27/2018 08:29 pm by Star One »

Offline Star One

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Astronomy Thread
« Reply #348 on: 02/28/2018 07:51 pm »
It’s not often that an astronomy story is the headline news story on a UK national newspaper website. Even a broadsheet like The Guardian.

Cosmic dawn: astronomers detect signals from first stars in the universe

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’Revolutionary’ observations suggest the first stars appeared 180m years after the big bang – and may hold information on dark matter

https://www.theguardian.com/science/2018/feb/28/cosmic-dawn-astronomers-detect-signals-from-first-stars-in-the-universe



And here’s the relevant paper.

An absorption profile centred at 78 megahertz in the sky-averaged spectrum

After stars formed in the early Universe, their ultraviolet light is expected, eventually, to have penetrated the primordial hydrogen gas and altered the excitation state of its 21-centimetre hyperfine line. This alteration would cause the gas to absorb photons from the cosmic microwave background, producing a spectral distortion that should be observable today at radio frequencies of less than 200 megahertz1. Here we report the detection of a flattened absorption profile in the sky-averaged radio spectrum, which is centred at a frequency of 78 megahertz and has a best-fitting full-width at half-maximum of 19 megahertz and an amplitude of 0.5 kelvin. The profile is largely consistent with expectations for the 21-centimetre signal induced by early stars; however, the best-fitting amplitude of the profile is more than a factor of two greater than the largest predictions2. This discrepancy suggests that either the primordial gas was much colder than expected or the background radiation temperature was hotter than expected. Astrophysical phenomena (such as radiation from stars and stellar remnants) are unlikely to account for this discrepancy; of the proposed extensions to the standard model of cosmology and particle physics, only cooling of the gas as a result of interactions between dark matter and baryons seems to explain the observed amplitude3. The low-frequency edge of the observed profile indicates that stars existed and had produced a background of Lyman-α photons by 180 million years after the Big Bang. The high-frequency edge indicates that the gas was heated to above the radiation temperature less than 100 million years later.

https://www.nature.com/articles/nature25792

And here’s the second related paper.

Possible interaction between baryons and dark-matter particles revealed by the first stars

The cosmic radio-frequency spectrum is expected to show a strong absorption signal corresponding to the 21-centimetre-wavelength transition of atomic hydrogen around redshift 20, which arises from Lyman-α radiation from some of the earliest stars1,2,3,4. By observing this 21-centimetre signal—either its sky-averaged spectrum5 or maps of its fluctuations, obtained using radio interferometers6,7—we can obtain information about cosmic dawn, the era when the first astrophysical sources of light were formed. The recent detection of the global 21-centimetre spectrum5 reveals a stronger absorption than the maximum predicted by existing models, at a confidence level of 3.8 standard deviations. Here we report that this absorption can be explained by the combination of radiation from the first stars and excess cooling of the cosmic gas induced by its interaction with dark matter8,9,10. Our analysis indicates that the spatial fluctuations of the 21-centimetre signal at cosmic dawn could be an order of magnitude larger than previously expected and that the dark-matter particle is no heavier than several proton masses, well below the commonly predicted mass of weakly interacting massive particles. Our analysis also confirms that dark matter is highly non-relativistic and at least moderately cold, and primordial velocities predicted by models of warm dark matter are potentially detectable. These results indicate that 21-centimetre cosmology can be used as a dark-matter probe.

https://www.nature.com/articles/nature25791
« Last Edit: 02/28/2018 07:59 pm by Star One »

Offline Star One

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Re: Astronomy Thread
« Reply #349 on: 02/28/2018 08:07 pm »
The moon formed inside a vaporized Earth synestia

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A new explanation for the Moon's origin has it forming inside the Earth when our planet was a seething, spinning cloud of vaporized rock, called a synestia. The new model led by researchers at the University of California, Davis and Harvard University resolves several problems in lunar formation and is published Feb. 28 in the Journal of Geophysical Research - Planets.

https://www.eurekalert.org/pub_releases/2018-02/uoc--tmf022718.php

Offline Star One

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Astronomy Thread
« Reply #350 on: 02/28/2018 08:51 pm »
« Last Edit: 02/28/2018 08:57 pm by Star One »

Online catdlr

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Re: Astronomy Thread
« Reply #351 on: 03/01/2018 08:53 am »
Want to See Space? Why Not Use One of NASA's Telescopes From the Comfort of Your Own Home

article: https://www.yahoo.com/news/want-see-space-why-not-155751923.html

Site: http://mo-www.harvard.edu/cgi-bin/OWN/Own.pl

Quote
Each of the telescopes can be operated remotely and do not require a human operator. They are capable of viewing the moon, the Orion Nebula or nearby planets and are even powerful enough to snap a picture of other galaxies.
Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Offline Star One

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Astronomy Thread
« Reply #352 on: 03/02/2018 08:37 pm »
HUBBLE OBSERVES EXOPLANET ATMOSPHERE IN MORE DETAIL THAN EVER BEFORE [HEIC1804]

01 March 2018
An international team of scientists has used the NASA/ESA Hubble Space Telescope to study the atmosphere of the hot exoplanet WASP-39b. By combining this new data with older data they created the most complete study yet of an exoplanet atmosphere. The atmospheric composition of WASP-39b hints that the formation processes of exoplanets can be very different from those of our own Solar System giants.

Investigating exoplanet atmospheres can provide new insight into how and where planets form around a star. "We need to look outward to help us understand our own Solar System," explains lead investigator Hannah Wakeford from the University of Exeter in the UK and the Space Telescope Science Institute in the USA.
Therefore the British-American team combined the capabilities of the NASA/ESA Hubble Space Telescope with those of other ground- and space-based telescopes for a detailed study of the exoplanet WASP-39b. They have produced the most complete spectrum of an exoplanet's atmosphere possible with present-day technology [1].
WASP-39b is orbiting a Sun-like star, about 700 light-years from Earth. The exoplanet is classified as a "Hot-Saturn", reflecting both its mass being similar to the planet Saturn in our own Solar System and its proximity to its parent star. This study found that the two planets, despite having a similar mass, are profoundly different in many ways. Not only is WASP-39b not known to have a ring system, it also has a puffy atmosphere that is free of high-altitude clouds. This characteristic allowed Hubble to peer deep into its atmosphere.
By dissecting starlight filtering through the planet's atmosphere [2] the team found clear evidence for atmospheric water vapour. In fact, WASP-39b has three times as much water as Saturn does. Although the researchers had predicted they would see water vapour, they were surprised by the amount that they found. This surprise, combined with the water abundance allowed to infer the presence of large amount of heavier elements in the atmosphere. This in turn suggests that the planet was bombarded by a lot of icy material which gathered in its atmosphere. This kind of bombardment would only be possible if WASP-39b formed much further away from its host star than it is right now.
"WASP-39b shows exoplanets are full of surprises and can have very different compositions than those of our Solar System," says co-author David Sing from the University of Exeter, UK.
The analysis of the atmospheric composition and the current position of the planet indicate that WASP-39b most likely underwent an interesting inward migration, making an epic journey across its planetary system. "Exoplanets are showing us that planet formation is more complicated and more confusing than we thought it was. And that's fantastic!", adds Wakeford.
Having made its incredible inward journey WASP-39b is now eight times closer to its parent star, WASP-39, than Mercury is to the Sun and it takes only four days to complete an orbit. The planet is also tidally locked, meaning it always shows the same side to its star. Wakeford and her team measured the temperature of WASP-39b to be a scorching 750 degrees Celsius. Although only one side of the planet faces its parent star, powerful winds transport heat from the bright side around the planet, keeping the dark side almost as hot.
"Hopefully this diversity we see in exoplanets will help us figure out all the different ways a planet can form and evolve," explains David Sing.
Looking ahead, the team wants to use the NASA/ESA/CSA James Webb Space Telescope – scheduled to launch in 2019 – to capture an even more complete spectrum of the atmosphere of WASP-39b. James Webb will be able to collect data about the planet's atmospheric carbon, which absorbs light of longer wavelengths than Hubble can see [3]. Wakeford concludes: "By calculating the amount of carbon and oxygen in the atmosphere, we can learn even more about where and how this planet formed."
NOTES
[1] Data used to produce the full spectrum was also collected by NASA's Spitzer Space Telescope and ESO's Very Large Telescope. In addition older data from Hubble were used.
[2] When starlight passes through the atmosphere of an exoplanet, it interacts with the atoms and molecules in it. This leaves a weak fingerprint of the atmosphere in the spectrum of the star. Certain peaks and troughs in the resulting spectrum correspond to specific atoms and molecules, allowing scientists to see exactly what gases make up the atmosphere.
[3] Given the large amount of heavy elements in WASP-39b's atmosphere, Wakeford and her team predict that carbon dioxide will be the dominant form of carbon. This could be measured at a wavelength of 4.5 micrometres with James Webb's NIRSpec instrument. Such follow-up investigations would allow further constraints to be placed on the ratio of carbon to oxygen, and on the metallicity of WASP-39b's atmosphere.
MORE INFORMATION
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

http://sci.esa.int/hubble/60022-hubble-observes-exoplanet-atmosphere-in-more-detail-than-ever-before-heic1804/
« Last Edit: 03/02/2018 08:41 pm by Star One »

Offline Star One

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Re: Astronomy Thread
« Reply #353 on: 03/02/2018 08:44 pm »
A Stellar System with Three Super Earths
Friday, March 2, 2018
Science Update - A look at CfA discoveries from recent journals
Over 3500 extra-solar planets have been confirmed to date. Most of them were discovered using the transit method, and astronomers can combine the transit light curves with velocity wobble observations to determine the planet's mass and radius, and thereby constrain its interior structure. The atmosphere can also be studied in a transit by using the fact that the chemical composition of the atmosphere means its opacity varies with wavelength. By measuring the depth of the transit at different wavelengths, it is possible to infer the composition and temperature of the planet's atmosphere.

CfA astronomers Joseph Rodriguez, Andrew Vanderburg, Jason Eastman, David Latham, and Samuel Quinn and their team of scientists discovered three small transiting planets orbiting the star GJ9827 which lies at the relatively close distance of 100 light-years. The three exoplanets have radii of about 1.6, 1.3, and 2.1 Earth-radii respectively. All of them are categorized as super-Earths, that is, with masses that are larger than Earth’s but less than Neptune's. (Radial velocity measurements of the exoplanets, not included in this paper, have just been separately published and confirm this conclusion.)

GJ9827 is one of the few known stars to have multiple transiting terrestrial-sized exoplanets that are suited for atmospheric characterization. In fact, its three exoplanets are particularly interesting because two of them have radii between 1.5 and 2.0 Earth-radii. Across this range in radii, the composition of planets is expected to change from rocky to gaseous; moreover, there are relatively few such candidates for study. These planets orbit very close to the star, with periods of 1.2, 3.6 and 6.2 days respectively, and at these close distances they have fairly hot temperatures, estimated at 1172, 811 and 680 degrees kelvin. Future observations will probe their atmospheres and provide a much more detailed picture of this unusual family of super-Earths.

Reference(s):
"A System of Three Super Earths Transiting the Late K-Dwarf GJ 9827 at 30 pc," Joseph E. Rodriguez, Andrew Vanderburg, Jason D. Eastman, Andrew W. Mann, Ian J. M. Crossfield, David R. Ciardi, David W. Latham, and Samuel N. Quinn, AJ 155, 72, 2018.

https://www.cfa.harvard.edu/news/su201809

Offline CuddlyRocket

Re: Astronomy Thread
« Reply #354 on: 03/03/2018 10:02 pm »
Yeah, I mentioned this paper on 8 February (Reply #333) with a link to the paper on arXiv (not a criticism, it's nearly a month ago and its difficult to remember everything!). Here's the link again: Magellan/PFS Radial Velocities of GJ 9827, a late K dwarf at 30 pc with Three Transiting Super-Earths

It seems that this 'radii gap' (sometimes referred to as the Fulton gap) is becoming more firmly established!

Offline Star One

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Re: Astronomy Thread
« Reply #355 on: 03/05/2018 07:36 pm »
DONOR STAR BREATHES LIFE INTO ZOMBIE COMPANION

ESA's INTEGRAL space observatory has witnessed a rare event: the moment that winds emitted by a swollen red giant star revived its slow-spinning companion, the core of a dead star, bringing it back to life in a flash of X-rays.

The X-ray flare was first detected by INTEGRAL on 13 August 2017 from an unknown source in the direction of the crowded centre of our Milky Way. The sudden detection triggered a slew of follow-up observations in the following weeks to pin down the culprit.
The observations revealed a strongly magnetised and slowly rotating neutron star that had likely just begun to feed on material from a neighbouring red giant star.
Stars the mass of our Sun, and up to eight times more massive, evolve into red giants towards the end of their lives. Their outer layers puff up and expand millions of kilometres, their dusty, gassy shells blown away from the central star in relatively slow winds up to few hundreds of km/s.
Even larger stars, up to 25–30 times more massive than the Sun, race through their fuel and explode in a supernova, sometimes leaving behind a spinning stellar corpse with a strong magnetic field, known as a neutron star. This tiny core packs the mass of nearly one and half Suns into a sphere only 10 km across, making them some of the densest celestial objects known.

It is not uncommon to find stars paired together, but the new system of a neutron star and red giant is a particularly rare breed known as a 'symbiotic X-ray binary', with no more than 10 known.
"INTEGRAL caught a unique moment in the birth of a rare binary system," says Enrico Bozzo from University of Geneva and lead author of the paper that describes the discovery. "The red giant released a sufficiently dense slow wind to feed its neutron star companion, giving rise to high-energy emission from the dead stellar core for the first time."
The pairing is certainly peculiar. ESA's XMM-Newton and NASA's NuSTAR space telescopes showed that the neutron star spins almost every two hours – very slow compared with other neutron stars, which can spin up to many times per second. Then, the first measurement of the magnetic field of such a neutron star revealed it to be surprisingly strong.
A strong magnetic field typically points to a young neutron star – the magnetic field is thought to fade over time – while a red giant is much older, making it a bizarre couple to have grown up together.
"These objects are puzzling," says Enrico. "It might be that either the neutron star magnetic field does not decay substantially with time after all, or the neutron star actually formed later in the history of the binary system. That would mean it collapsed from a white dwarf into a neutron star as a result of feeding off the red giant over a long time, rather than becoming a neutron star as a result of a more traditional supernova explosion of a short-lived massive star."
With a young neutron star and an old red giant, at some point the winds travelling from the puffed-up giant will begin to rain on to the smaller star, slowing its spin and emitting X-rays.
"We haven't seen this object before in the past 15 years of our observations with INTEGRAL, so we believe we saw the X-rays turning on for the first time," says Erik Kuulkers, ESA's INTEGRAL project scientist. "We'll continue to watch how it behaves in case it is just a long 'burp' of winds, but so far we haven't seen any significant changes."
NOTES FOR EDITORS
"IGR J17329-2731: The birth of a symbiotic X-ray binary," by E. Bozzo et al. is accepted for publication in Astronomy & Astrophysics.
The rapid response of the follow-up observations was enabled by the SmartNet community. This included important contributions from ESA's XMM-Newton and NASA’s NuSTARand Swift space telescopes, and the ground-based Southern Astrophysical Research Telescope, Faulkes Telescopes North and South and the Las Cumbres Observatory.

http://sci.esa.int/integral/60029-donor-star-breathes-life-into-zombie-companion/

Offline CuddlyRocket

Re: Astronomy Thread
« Reply #356 on: 03/06/2018 01:35 am »
Konstantin Batygin has a new paper out. Here's the Caltech release:

Massive Astrophysical Objects Governed by Subatomic Equation
The Schrödinger Equation makes an unlikely appearance at the astronomical scale


The paper itself can be found here (pdf):

Schrodinger evolution of self-gravitating discs

Quote
(Abstract)
An understanding of the long-term evolution of self-gravitating discs ranks among the classic outstanding problems of astrophysics. In this work, we show that the secular inclination dynamics of a geometrically thin quasi-Keplerian disc, with a surface density profile that scales as the inverse square-root of the orbital radius, are described by the time-dependent Schrodinger equation. Within the context of this formalism, nodal bending waves correspond to the eigenmodes of a quasi-particle’s wavefunction, confined in an infinite square well with boundaries given by the radial extent of the disc. We further show that external secular perturbations upon self-gravitating discs exhibit a mathematical similarity to quantum scattering theory. Employing this framework, we derive an analytic criterion for the gravitational rigidity of a nearly-Keplerian disc under external perturbations. Applications of the theory to circumstellar discs and Galactic nuclei are discussed.

As you might expect from one of Konstantin's papers, it's a bit mathematical!

Offline Star One

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Re: Astronomy Thread
« Reply #357 on: 03/07/2018 08:37 am »
Massive Astrophysical Objects Governed by Subatomic Equation

Quote
The Schrödinger Equation makes an unlikely appearance at the astronomical scale

Quantum mechanics is the branch of physics governing the sometimes-strange behavior of the tiny particles that make up our universe. Equations describing the quantum world are generally confined to the subatomic realm—the mathematics relevant at very small scales is not relevant at larger scales, and vice versa. However, a surprising new discovery from a Caltech researcher suggests that the Schrödinger Equation—the fundamental equation of quantum mechanics—is remarkably useful in describing the long-term evolution of certain astronomical structures.

http://m.caltech.edu/news/massive-astrophysical-objects-governed-subatomic-equation-81517

Offline Star One

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Re: Astronomy Thread
« Reply #358 on: 03/07/2018 07:24 pm »
eso1809 — Photo Release

ALMA Reveals Inner Web of Stellar Nursery

New data from the Atacama Large Millimeter/submillimeter Array (ALMA) and other telescopes have been used to create this stunning image showing a web of filaments in the Orion Nebula. These features appear red-hot and fiery in this dramatic picture, but in reality are so cold that astronomers must use telescopes like ALMA to observe them.

This spectacular and unusual image shows part of the famous Orion Nebula, a star formation region lying about 1350 light-years from Earth. It combines a mosaic of millimetre-wavelength images from the Atacama Large Millimeter/submillimeter Array (ALMA) and the IRAM 30-metre telescope, shown in red, with a more familiar infrared view from the HAWK-I instrument on ESO’s Very Large Telescope, shown in blue. The group of bright blue-white stars at the upper-left is the Trapezium Cluster — made up of hot young stars that are only a few million years old.

The wispy, fibre-like structures seen in this large image are long filaments of cold gas, only visible to telescopes working in the millimetre wavelength range. They are invisible at both optical and infrared wavelengths, making ALMA one of the only instruments available for astronomers to study them. This gas gives rise to newborn stars — it gradually collapses under the force of its own gravity until it is sufficiently compressed to form a protostar — the precursor to a star.

The scientists who gathered the data from which this image was created were studying these filaments to learn more about their structure and make-up. They used ALMA to look for signatures of diazenylium gas, which makes up part of these structures. Through doing this study, the team managed to identify a network of 55 filaments.

The Orion Nebula is the nearest region of massive star formation to Earth, and is therefore studied in great detail by astronomers seeking to better understand how stars form and evolve in their first few million years. ESO’s telescopes have observed this interesting region multiple times, and you can learn more about previous discoveries here, here, and here.

This image combines a total of 296 separate individual datasets from the ALMA and IRAM telescopes, making it one of the largest high-resolution mosaics of a star formation region produced so far at millimetre wavelengths [1].

Notes
[1] Earlier mosaics of Orion at millimetre wavelengths had used single-dish telescopes, such as APEX. The new observations from ALMA and IRAM use interferometry to combine the signals from multiple, widely-separated antennas to create images showing much finer detail.

http://www.eso.org/public/news/eso1809/

Offline Star One

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Re: Astronomy Thread
« Reply #359 on: 03/08/2018 11:07 am »
Enceladus and the Conditions for Life


 

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