Photographing The Milky Way Over Greece

Stellar Outburst Brings Water Snow Line Into View

ESO - European Southern Observatory logo. 13 July 2016

Artist’s impression of the water snowline around the young star V883 Orionis

The Atacama Large Millimeter/submillimeter Array (ALMA) has made the first ever resolved observation of a water snow line within a protoplanetary disc. This line marks where the temperature in the disc surrounding a young star drops sufficiently low for snow to form. A dramatic increase in the brightness of the young star V883 Orionis flash heated the inner portion of the disc, pushing the water snow line out to a far greater distance than is normal for a protostar, and making it possible to observe it for the first time. The results are published in the journal Nature on 14 July 2016.

ALMA image of the protoplanetary disc around V883 Orionis

Young stars are often surrounded by dense, rotating discs of gas and dust, known as protoplanetary discs, from which planets are born. The heat from a typical young solar-type star means that the water within a protoplanetary disc is gaseous up to distances of around 3 au from the star [1] — less than 3 times the average distance between the Earth and the Sun — or around 450 million kilometres [2]. Further out, due to the extremely low pressure, the water molecules transition directly from a gaseous state to form a patina of ice on dust grains and other particles. The region in the protoplanetary disc where water transitions between the gas and solid phases is known as the water snow line [3].

The star V883 Orionis in the constellation of Orion

But the star V883 Orionis is unusual. A dramatic increase in its brightness has pushed the water snow line out to a distance of around 40 au (about 6 billion kilometres or roughly the size of the orbit of the dwarf planet Pluto in our Solar System). This huge increase, combined with the resolution of ALMA at long baselines [4], has allowed a team led by Lucas Cieza (Millennium ALMA Disk Nucleus and Universidad Diego Portales, Santiago, Chile) to make the first ever resolved observations of a water snow line in a protoplanetary disc.

Shifting water snowline in V883 Orionis

The sudden brightening that V883 Orionis experienced is an example of what occurs when large amounts of material from the disc surrounding a young star fall onto its surface. V883 Orionis is only 30% more massive than the Sun, but thanks to the outburst it is experiencing, it is currently a staggering 400 times more luminous — and much hotter [5].

ALMA image of the protoplanetary disc around V883 Orionis (annotated)

Lead author Lucas Cieza explains: “The ALMA observations came as a surprise to us. Our observations were designed to look for disc fragmentation leading to planet formation. We saw none of that; instead, we found what looks like a ring at 40 au. This illustrates well the transformational power of ALMA, which delivers exciting results even if they are not the ones we were looking for.”

ALMA image of the protoplanetary disc around V883 Orionis

The bizarre idea of snow orbiting in space is fundamental to planet formation. The presence of water ice regulates the efficiency of the coagulation of dust grains — the first step in planet formation. Within the snow line, where water is vapourised, smaller, rocky planets like our own are believed to form. Outside the water snow line, the presence of water ice allows the rapid formation of cosmic snowballs, which eventually go on to form massive gaseous planets such as Jupiter.

Zooming on the protoplanetary disc around V883 Orionis

The discovery that these outbursts may blast the water snow line to about 10 times its typical radius is very significant for the development of good planetary formation models. Such outbursts are believed to be a stage in the evolution of most planetary systems, so this may be the first observation of a common occurrence. In that case, this observation from ALMA could contribute significantly to a better understanding of how planets throughout the Universe formed and evolved.

The protoplanetary disc around V883 Orionis (artist’s impression)

Notes: [1] 1 au, or one astronomical unit, is the mean distance between the Earth and the Sun, around 149.6 million kilometres.This unit is typically used to describe distances measured within the Solar System and planetary systems around other stars. [2] This line was between the orbits of Mars and Jupiter during the formation of the Solar System, hence the rocky planets Mercury, Venus, Earth and Mars formed within the line, and the gaseous planets Jupiter, Saturn, Uranus and Neptune formed outside. [3] The snow lines for other molecules, such as carbon monoxide and methane, have been observed previously with ALMA, at distances of greater than 30 au from the protostar within other protoplanetary discs. Water freezes at a relatively high temperature and this means that the water snow line is usually much too close to the protostar to observe directly. [4] Resolution is the ability to discern that objects are separate. To the human eye, several bright torches at a distance would seem like a single glowing spot, and only at closer quarters would each torch be distinguishable. The same principle applies to telescopes, and these new observations have exploited the exquisite resolution of ALMA in its long baseline modes. The resolution of ALMA at the distance of V883 Orionis is about 12 au — enough to resolve the water snow line at 40 au in this outbursting system, but not for a typical young star. [5] Stars like V883 Orionis are classed as FU Orionis stars, after the original star that was found to have this behaviour. The outbursts may last for hundreds of years. More information: This research was presented in a paper entitled “Imaging the water snow-line during a protostellar outburst”, by L. Cieza et al., to appear in Nature on 14 July 2016. The team is composed of Lucas A. Cieza (Millennium ALMA Disk Nucleus; Universidad Diego Portales, Santiago, Chile), Simon Casassus (Universidad de Chile, Santiago, Chile), John Tobin (Leiden Observatory, Leiden University, The Netherlands), Steven Bos (Leiden Observatory, Leiden University, The Netherlands), Jonathan P. Williams (University of Hawaii at Manoa, Honolulu, Hawai`i, USA), Sebastian Perez (Universidad de Chile, Santiago, Chile), Zhaohuan Zhu (Princeton University, Princeton, New Jersey, USA), Claudio Cáceres (Universidad Valparaiso, Valparaiso, Chile), Hector Canovas (Universidad Valparaiso, Valparaiso, Chile), Michael M. Dunham (Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA), Antonio Hales (Joint ALMA Observatory, Santiago, Chile), Jose L. Prieto (Universidad Diego Portales, Santiago, Chile), David A. Principe (Universidad Diego Portales, Santiago, Chile), Matthias R. Schreiber (Universidad Valparaiso, Valparaiso, Chile), Dary Ruiz-Rodriguez (Australian National University, Mount Stromlo Observatory, Canberra, Australia) and Alice Zurlo (Universidad Diego Portales & Universidad de Chile, Santiago, Chile). The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA. ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”. Links: Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1626/eso1626a.pdf Photos of ALMA: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Atacama%20Large%20Millimeter/submillimeter%20Array For more information about ALMA, visit: https://www.eso.org/sci/facilities/alma.html Images, Text, Credits: ESO/Richard Hook/A. Angelich (NRAO/AUI/NSF)/ALMA (ESO/NAOJ/NRAO)/ALMA//L. Cieza/IAU and Sky & Telescope/Videos: ALMA (ESO/NAOJ/NRAO)/L. Cieza./ESO/Digitized Sky Survey 2/N. Risinger (skysurvey.org)/M. Kornmesser. Music: Johan B. Monell. Best regards, Orbiter.ch Full article

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Oculus Superum, Red Nebula

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Some galaxies have extremely bright cores, suggesting that they contain a supermassive black hole that is pulling in matter at a prodigious rate. Astronomers call these “active galaxies,” and Hercules A is one of them. In visible light, Hercules A looks like a typical elliptical galaxy. In X-ray light, however, Chandra detects a giant cloud of multimillion-degree gas (purple). This gas has been heated by energy generated by the infall of matter into a black hole at the center of Hercules A that is over 1,000 times as massive as the one in the middle of the Milky Way. Radio data (blue) show jets of particles streaming away from the black hole. The jets span a length of almost one million light years.  

Credit: X-ray: NASA/CXC/SAO, Optical: NASA/STScI, Radio: NSF/NRAO/VLA

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Skull of a woman with monocephalus diprosopus. This is a form of conjoined twinning characterized by a single head and two faces. From the Museum of Anatomy in Montpellier, France.

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Tardigrades: ‘Water bears’ stuck on the moon after crash 

The moon might now be home to thousands of planet Earth’s most indestructible animals.

Tardigrades - often called water bears - are creatures under a millimetre long that can survive being heated to 150C and frozen to almost absolute zero.

They were travelling on an Israeli spacecraft that crash-landed on the moon in April.

And the co-founder of the organisation that put them there thinks they’re almost definitely still alive.

The water bears had been dehydrated to place them in suspended animation and then encased in artificial amber.

“We believe the chances of survival for the tardigrades… are extremely high.”

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The Perseid meteor shower over Mt. Hood

Source: https://imgur.com/ssijwh2

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A Super-Black Coating by Surrey NanoSystems.

This product absorbs 99.7% of light at 600nm wavelength. Unlike the previous product, VantaBlack, this product is much more tolerant and can withstand handling - indicating more realistic worldwide applications. 

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i get a LOT of questions about time management and getting better grades so i decided to put a boat load of advice and links in one place :]

time management methods

start a bullet journal ( +mine / +insp )

the 5 day study plan - it works!

schedule blocks of study time

use excel to schedule study

how to schedule study

the sticky note method

an app that organizes time for u

15 ways to beat procrastination

balancing multiple AP classes

decision making and time management

use the pomodoro technique

the task box prioritizing method

how to cram a lot of information in

get organized!!!!!

make and use a syllabible

great organization advice

organize ur study space

more tips on study spaces

basic organization tips

cute infographic

printable planner sheets

simple 2 pocket folder method

study methods!!!

watch youtube crashcourses

best study tips ever tbh

tips on memorizing effectively

add color for visual interest

make cause and effect diagrams

making good flashcards

create summary foldables

margin note taking

the 2 notebook method

for when ur not motivated

reading long textbook passages

studying for a test ooh

basic note taking

+note taking tips

note taking in microsoft word

bs study guide

how to plan out an essay

more essay planning

annotating literature for english

how to make concept maps

really interesting way of studying

shit load of study methods

web resources!!!!

search engine that plants trees!

to do list web program

bedtime calculator [avoid grogginess]

the dictionaries u need omg

how to pull an all nighter

advice on how to properly use google

final grade calculator

>100 places to download literature

cute af school supply list

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best writing checker ever its my fave

free academic journals for research

AP cramming packets

every website to make a bibliography

online used book store

mind map making software from tufts

khanacademy aka bless this site

stop procrastinating websites

free powerpoint

awesome synonym finder

apps u need to download!!!

google chrome app i love it

taking digital notes

like 14 useful school apps

attn: all writers get this

super cute time manager

>9 different studying apps

post it note app

study + give water to needy!!

relaxation n meditation help

sat help!!!!!

all kinds of essential vocab [2k+]

big collection of links

v solid page with lots of references

rly good advice imo

how to do well on the sat

general big exam advices

stress reliefs!!!!

rly good study snacks

badass instrumental playlist!

finish ur essay songs!

+all my fave study playlists!

treat urself on a low budget

read some rad articles

teach urself computer science

take the 10 day study challenge

rip some crap online

good things to do in study breaks

+100 more things in study breaks

if u tired and uninspired

avoid student burnout

watch a ton of broadway musicals

nice things for urself

anxiety relieving background sound

+masterposts!!!

back to school advice

productive summers

note taking methods

starting a study blog

time managements

succeed @ school

ap world history

study instagram

web resources

ap psychology

bullet journals

school advice

happy things

ace ur exams

study sounds

stress reliefs

annotations

essay writin

study 101

printables

sat help

+more

i hope some of this was helpful ~ i also have a youtube channel and instagram account with a whole bunch of study resources!!!!  ~ xoxo sareena

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ELISA

Enzyme-linked immunosorbent assay is a plate-based assay technique used to detect substances such as proteins, peptides and hormones. 

An antigen is immobilized on a solid surface 

It is complexed with an antibody that is linked to an enzyme.

The conjugated enzyme activity is assessed via incubation with a substrate.

Which produces a product that can be measured. 

Direct ELISA

Antigen is coated directly to wells of microtitre plate 

an enzyme-labelled primary antibody that detects the antigen is added.

Advantages  

Fast and minimal steps needed.

Minimum precursor requirement makes it less error prone.

Disadvantages

The immobilization of the antigen is not specific - background interference.

Less flexibility of primary antibody.

No signal amplification –> less sensitivity.

Indirect ELISA

An enzyme labelled secondary antibody interacts with a primary antibody to increase sensitivity. 

Advantages

Offers high sensitivity and flexibility as a secondary antibody can label different primary antibodies

It is cheap (fewer labelled antibodies needed)

Disadvantages

Increased background noise from the secondary antibody.

Extra labour.

Sandwich ELISA

Capture antibody bound to surface.

Antigen-containing sample is applied and captured.

A specific antibody is added, and binds to antigen (sandwiching the antigen between 2 antibodies). 

Enzyme-linked secondary antibodies are used as detection antibodies.

Advantages  

Offers high sensitivity and a highly specific reaction due to 2 antibodies (both have to bind to the antigen).

Disadvantages

For recognition of a specific epitope, only monoclonal antibodies can be applied as matched pairs.

Procuring monoclonal antibodies is difficult and expensive.

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I…am calm

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