A full circle rainbow over Australia

Have you ever seen an entire rainbow? From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360 degree circle of a rainbow is more commonly visible. Pictured here, a full circle rainbow was captured over Cottesloe Beach near Perth, Australia last year by a helicopter flying between a setting sun and a downpour. An observer-dependent phenomenon primarily caused by the internal reflection of sunlight by raindrops, the 84-degree diameter rainbow followed the helicopter, intact, for about 5 kilometers. As a bonus, a second rainbow that was more faint and color-reversed was visible outside the first.

Image credit & copyright: Colin Leonhardt (Birdseye View Photography)

A full circle rainbow over Australia

Have you ever seen an entire rainbow? From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360 degree circle of a rainbow is more commonly visible. Pictured here, a full circle rainbow was captured over Cottesloe Beach near Perth, Australia last year by a helicopter flying between a setting sun and a downpour. An observer-dependent phenomenon primarily caused by the internal reflection of sunlight by raindrops, the 84-degree diameter rainbow followed the helicopter, intact, for about 5 kilometers. As a bonus, a second rainbow that was more faint and color-reversed was visible outside the first.

Image credit & copyright: Colin Leonhardt (Birdseye View Photography)

(Source: apod.nasa.gov)

Milky Way over Fünfländerblick

'FünfländerblickMilchstrasse,’ the Milky Way over a dark country sky in Switzerland.

Image credit and copyright: Christian Kamber

Milky Way over Fünfländerblick

'FünfländerblickMilchstrasse,’ the Milky Way over a dark country sky in Switzerland.

Image credit and copyright: Christian Kamber

(Source: universetoday.com)


Fall colors arriving







A few days after autumn showed up on the calendar in the Northern Hemisphere, it showed up on the landscape of North America. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this view of fall colors around the Great Lakes on Sept. 26, 2014.
The changing of leaf color in temperate forests involves several causes and reactions, but the dominant factors are sunlight and heat. Since temperatures tend to drop sooner and sunlight fades faster at higher latitudes, the progression of fall color changes tends to move from north to south across North America from mid-September through mid-November.
In late summer and autumn, tree and plant leaves produce less chlorophyll, the green pigment that harvests sunlight for plants to convert water and carbon dioxide into sugars. The subsidence of chlorophyll allows other chemical compounds in the leaves—particularly carotenoids and flavonoids—to emerge from the green shadow of summer. These compounds do not decay as fast as chlorophyll, so they shine through in yellows, oranges, and reds as the green fades. Another set of chemicals, anthocyanins, are associated with the storage of sugars and give the leaves of some species deep purple and red hues.

Image credit: Jeff Schmaltz at NASA GSFC. Caption by Mike Carlowicz

Fall colors arriving

A few days after autumn showed up on the calendar in the Northern Hemisphere, it showed up on the landscape of North America. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this view of fall colors around the Great Lakes on Sept. 26, 2014.

The changing of leaf color in temperate forests involves several causes and reactions, but the dominant factors are sunlight and heat. Since temperatures tend to drop sooner and sunlight fades faster at higher latitudes, the progression of fall color changes tends to move from north to south across North America from mid-September through mid-November.

In late summer and autumn, tree and plant leaves produce less chlorophyll, the green pigment that harvests sunlight for plants to convert water and carbon dioxide into sugars. The subsidence of chlorophyll allows other chemical compounds in the leaves—particularly carotenoids and flavonoids—to emerge from the green shadow of summer. These compounds do not decay as fast as chlorophyll, so they shine through in yellows, oranges, and reds as the green fades. Another set of chemicals, anthocyanins, are associated with the storage of sugars and give the leaves of some species deep purple and red hues.

Image credit: Jeff Schmaltz at NASA GSFC. Caption by Mike Carlowicz

(Source: nasa.gov)

Snapshot of a shedding star

In this new Hubble image, the strikingly luminous star AG Carinae — otherwise known as HD 94910 — takes centre stage. Found within the constellation of Carina in the southern sky, AG Carinae lies 20 000 light-years away, nestled in the Milky Way.
AG Carinae is classified as a Luminous Blue Variable. These rare objects are massive evolved stars that will one day become Wolf-Rayet Stars — a class of stars that are tens of thousands to several million times as luminous as the Sun. They have evolved from main sequence stars that were twenty times the mass of the Sun.
Stars like AG Carinae lose their mass at a phenomenal rate. This loss of mass is due to powerful stellar winds with speeds of up to 7 million km/hour. These powerful winds are also responsible for the shroud of material visible in this image. The winds exert enormous pressure on the clouds of interstellar material expelled by the star and force them into this shape.
Despite HD 94910’s intense luminosity, it is not visible with the naked eye as much of its output is in the ultraviolet.


Image credit: ESA/Hubble & NASA

Snapshot of a shedding star

In this new Hubble image, the strikingly luminous star AG Carinae — otherwise known as HD 94910 — takes centre stage. Found within the constellation of Carina in the southern sky, AG Carinae lies 20 000 light-years away, nestled in the Milky Way.

AG Carinae is classified as a Luminous Blue Variable. These rare objects are massive evolved stars that will one day become Wolf-Rayet Stars — a class of stars that are tens of thousands to several million times as luminous as the Sun. They have evolved from main sequence stars that were twenty times the mass of the Sun.

Stars like AG Carinae lose their mass at a phenomenal rate. This loss of mass is due to powerful stellar winds with speeds of up to 7 million km/hour. These powerful winds are also responsible for the shroud of material visible in this image. The winds exert enormous pressure on the clouds of interstellar material expelled by the star and force them into this shape.

Despite HD 94910’s intense luminosity, it is not visible with the naked eye as much of its output is in the ultraviolet.

Image credit: ESA/Hubble & NASA

(Source: spacetelescope.org)

An emu in the sky over Paranal


Sitting atop Cerro Paranal high above the Atacama Desert in Chile, two of the Very Large Telescope’s Unit Telescopes quietly bask in the starlight, observing the Milky Way as it arches over ESO’s Paranal Observatory.



Several interesting objects can be seen in this picture. Some of the most prominent are the two Magellanic Clouds — one Small (SMC), one Large (LMC) — which appear brightly in between the two telescopes. By contrast, the dark Coalsack Nebula can be seen as an obscuring smudge across the Milky Way, resembling a giant cosmic thumbprint above the telescope on the left.
The Magellanic Clouds are both located within the Local Group of galaxies that includes our galaxy, the Milky Way. The LMC lies at a distance of 163 000 light-years from our galaxy, and the SMC at 200 000 light-years. The Coalsack Nebula, on the other hand, is a mere stone’s throw away in comparison. At roughly 600 light-years from the Solar System, it is the most visible dark nebula in our skies.
The Coalsack has been recorded by many ancient cultures, and is identified as the head of the Emu in the Sky by several indigenous Australian groups. Aboriginal Australians are most likely the oldest practitioners of astronomy in the world, and they identify their constellations by use of dark nebulae — as opposed to stars, as is the Western tradition.
In the Southern hemisphere, these dark clouds are more prominent than in the Northern sky. Other cultures also had dark constellations — for example, the Inca in South America. A particularly important constellation to the Inca astronomers was one known as Urcuchillay (The Llama), representing the significance of the animals in their culture as a source of food, wool, and transport.

Image credit: ESO/Y. Beletsky

An emu in the sky over Paranal

Sitting atop Cerro Paranal high above the Atacama Desert in Chile, two of the Very Large Telescope’s Unit Telescopes quietly bask in the starlight, observing the Milky Way as it arches over ESO’s Paranal Observatory.

Several interesting objects can be seen in this picture. Some of the most prominent are the two Magellanic Clouds — one Small (SMC), one Large (LMC) — which appear brightly in between the two telescopes. By contrast, the dark Coalsack Nebula can be seen as an obscuring smudge across the Milky Way, resembling a giant cosmic thumbprint above the telescope on the left.

The Magellanic Clouds are both located within the Local Group of galaxies that includes our galaxy, the Milky Way. The LMC lies at a distance of 163 000 light-years from our galaxy, and the SMC at 200 000 light-years. The Coalsack Nebula, on the other hand, is a mere stone’s throw away in comparison. At roughly 600 light-years from the Solar System, it is the most visible dark nebula in our skies.

The Coalsack has been recorded by many ancient cultures, and is identified as the head of the Emu in the Sky by several indigenous Australian groups. Aboriginal Australians are most likely the oldest practitioners of astronomy in the world, and they identify their constellations by use of dark nebulae — as opposed to stars, as is the Western tradition.

In the Southern hemisphere, these dark clouds are more prominent than in the Northern sky. Other cultures also had dark constellations — for example, the Inca in South America. A particularly important constellation to the Inca astronomers was one known as Urcuchillay (The Llama), representing the significance of the animals in their culture as a source of food, wool, and transport.

Image credit: ESO/Y. Beletsky

(Source: eso.org)

Unusual rocks near Pahrump Hills on Mars

How did these Martian rocks form? As the robotic Curiosity rover has approached Pahrump Hills on Mars, it has seen an interesting and textured landscape dotted by some unusual rocks. The featured image shows a curiously round rock spanning about two centimeters across. Seemingly a larger version of numerous spherules dubbed blueberries found by the Opportunity rover on Mars in 2004, what caused this roundness remains unknown. Possibilities include frequent tumbling in flowing water, sprayed molten rock in a volcanic eruption, or a concretion mechanism. The inset image, taken a few days later, shows another small but unusually shaped rock structure. As Curiosity rolls around and up Mount Sharp, different layers of the landscape will be imaged and studied to better understand the ancient history of the region and to investigate whether Mars could once have harbored life.

Image credit: NASA, JPL-Caltech, MSSS

Unusual rocks near Pahrump Hills on Mars

How did these Martian rocks form? As the robotic Curiosity rover has approached Pahrump Hills on Mars, it has seen an interesting and textured landscape dotted by some unusual rocks. The featured image shows a curiously round rock spanning about two centimeters across. Seemingly a larger version of numerous spherules dubbed blueberries found by the Opportunity rover on Mars in 2004, what caused this roundness remains unknown. Possibilities include frequent tumbling in flowing water, sprayed molten rock in a volcanic eruption, or a concretion mechanism. The inset image, taken a few days later, shows another small but unusually shaped rock structure. As Curiosity rolls around and up Mount Sharp, different layers of the landscape will be imaged and studied to better understand the ancient history of the region and to investigate whether Mars could once have harbored life.

Image credit: NASA, JPL-Caltech, MSSS

(Source: apod.nasa.gov)

thedemon-hauntedworld:

Running Chicken Nebula  IC 2944, IC 2948 in Centaurus
Credit: Ivan Eder

thedemon-hauntedworld:

Running Chicken Nebula
IC 2944, IC 2948 in Centaurus

Credit: Ivan Eder

MAVEN at Mars

Launched on November 18, 2013, the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft completed its interplanetary voyage September 21, captured into a wide, elliptical orbit around Mars. MAVEN’s imaging ultraviolet spectrograph has already begun its planned exploration of the Red Planet’s upper atmosphere, acquiring this image data from an altitude of 36,500 kilometers. In false color, the three ultraviolet wavelength bands show light reflected from atomic hydrogen (in blue), atomic oxygen (in green) and the planet’s surface (in red). Low mass atomic hydrogen is seen to extend thousands of kilometers into space, with the cloud of more massive oxygen atoms held closer by Mars’ gravity. Both are by products of the breakdown of water and carbon dioxide in Mars’ atmosphere and the MAVEN data can be used to determine the rate of water loss over time. In fact, MAVEN is the first mission dedicated to exploring Mars’ tenuous upper atmosphere, ionosphere and interactions with the Sun and solar wind. But the most recent addition to the fleet of spacecraft from planet Earth now in martian orbit is MOM.

Image credit: MAVEN, Laboratory for Atmospheric and Space Physics, Univ. Colorado, NASA

MAVEN at Mars

Launched on November 18, 2013, the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft completed its interplanetary voyage September 21, captured into a wide, elliptical orbit around Mars. MAVEN’s imaging ultraviolet spectrograph has already begun its planned exploration of the Red Planet’s upper atmosphere, acquiring this image data from an altitude of 36,500 kilometers. In false color, the three ultraviolet wavelength bands show light reflected from atomic hydrogen (in blue), atomic oxygen (in green) and the planet’s surface (in red). Low mass atomic hydrogen is seen to extend thousands of kilometers into space, with the cloud of more massive oxygen atoms held closer by Mars’ gravity. Both are by products of the breakdown of water and carbon dioxide in Mars’ atmosphere and the MAVEN data can be used to determine the rate of water loss over time. In fact, MAVEN is the first mission dedicated to exploring Mars’ tenuous upper atmosphere, ionosphere and interactions with the Sun and solar wind. But the most recent addition to the fleet of spacecraft from planet Earth now in martian orbit is MOM.

Image credit: MAVEN, Laboratory for Atmospheric and Space Physics, Univ. Colorado, NASA

(Source: apod.nasa.gov)


Expedition 41 crew launches to the International Space Station







The Soyuz TMA-14M rocket is launched with Expedition 41 Soyuz Commander Alexander Samokutyaev of the Russian Federal Space Agency (Roscosmos) Flight Engineer Elena Serova of Roscosmos, and Flight Engineer Barry Wilmore of NASA, Friday, Sept. 26, 2014 at the Baikonur Cosmodrome in Kazakhstan. Samokutyaev, Serova, and Wilmore will spend the next five and a half months aboard the International Space Station. Serova will become the fourth Russian woman to fly in space and the first Russian woman to live and work on the station.

Image credit: NASA/Joel Kowsky

Expedition 41 crew launches to the International Space Station

The Soyuz TMA-14M rocket is launched with Expedition 41 Soyuz Commander Alexander Samokutyaev of the Russian Federal Space Agency (Roscosmos) Flight Engineer Elena Serova of Roscosmos, and Flight Engineer Barry Wilmore of NASA, Friday, Sept. 26, 2014 at the Baikonur Cosmodrome in Kazakhstan. Samokutyaev, Serova, and Wilmore will spend the next five and a half months aboard the International Space Station. Serova will become the fourth Russian woman to fly in space and the first Russian woman to live and work on the station.

Image credit: NASA/Joel Kowsky

(Source: nasa.gov)

A galaxy of deception



Astronomers usually have to peer very far into the distance to see back in time, and view the Universe as it was when it was young. This new NASA/ESA Hubble Space Telescope image of galaxy DDO 68, otherwise known as UGC 5340, was thought to offer an exception. This ragged collection of stars and gas clouds looks at first glance like a recently-formed galaxy in our own cosmic neighbourhood. But, is it really as young as it looks?
Astronomers have studied galactic evolution for decades, gradually improving our knowledge of how galaxies have changed over cosmic history. The NASA/ESA Hubble Space Telescope has played a big part in this, allowing astronomers to see further into the distance, and hence further back in time, than any telescope before it — capturing light that has taken billions of years to reach us.
Looking further into the very distant past to observe younger and younger galaxies is very valuable, but it is not without its problems for astronomers. All newly-born galaxies lie very far away from us and appear very small and faint in the images. On the contrary, all the galaxies near to us appear to be old ones.
DDO 68, captured here by the NASA/ESA Hubble Space Telescope, was one of the best candidates so far discovered for a newly-formed galaxy in our cosmic neighbourhood. The galaxy lies around 39 million light-years away from us; although this distance may seem huge, it is in fact roughly 50 times closer than the usual distances to such galaxies, which are on the order of several billions of light years.
By studying galaxies of various ages, astronomers have found that those early in their lives are fundamentally different from those that are older. DDO 68 looks to be relatively youthful based on its structure, appearance, and composition. However, without more detailed modelling astronomers cannot be sure and they think it may be older than it lets on.
Elderly galaxies tend to be larger thanks to collisions and mergers with other galaxies that have bulked them out, and are populated with a variety of different types of stars — including old, young, large, and small ones. Their chemical makeup is different too. Newly-formed galaxies have a similar composition to the primordial matter created in the Big Bang (hydrogen, helium and a little lithium), while older galaxies are enriched with heavier elements forged in stellar furnaces over multiple generations of stars.
DDO 68 is the best representation yet of a primordial galaxy in the local Universe as it appears at first glance to be very low in heavier elements — whose presence would be a sign of the existence of previous generations of stars.


Image credit: NASA & ESA; Acknowledgement: A. Aloisi (Space Telescope Science Institute)

A galaxy of deception

Astronomers usually have to peer very far into the distance to see back in time, and view the Universe as it was when it was young. This new NASA/ESA Hubble Space Telescope image of galaxy DDO 68, otherwise known as UGC 5340, was thought to offer an exception. This ragged collection of stars and gas clouds looks at first glance like a recently-formed galaxy in our own cosmic neighbourhood. But, is it really as young as it looks?

Astronomers have studied galactic evolution for decades, gradually improving our knowledge of how galaxies have changed over cosmic history. The NASA/ESA Hubble Space Telescope has played a big part in this, allowing astronomers to see further into the distance, and hence further back in time, than any telescope before it — capturing light that has taken billions of years to reach us.

Looking further into the very distant past to observe younger and younger galaxies is very valuable, but it is not without its problems for astronomers. All newly-born galaxies lie very far away from us and appear very small and faint in the images. On the contrary, all the galaxies near to us appear to be old ones.

DDO 68, captured here by the NASA/ESA Hubble Space Telescope, was one of the best candidates so far discovered for a newly-formed galaxy in our cosmic neighbourhood. The galaxy lies around 39 million light-years away from us; although this distance may seem huge, it is in fact roughly 50 times closer than the usual distances to such galaxies, which are on the order of several billions of light years.

By studying galaxies of various ages, astronomers have found that those early in their lives are fundamentally different from those that are older. DDO 68 looks to be relatively youthful based on its structure, appearance, and composition. However, without more detailed modelling astronomers cannot be sure and they think it may be older than it lets on.

Elderly galaxies tend to be larger thanks to collisions and mergers with other galaxies that have bulked them out, and are populated with a variety of different types of stars — including old, young, large, and small ones. Their chemical makeup is different too. Newly-formed galaxies have a similar composition to the primordial matter created in the Big Bang (hydrogen, helium and a little lithium), while older galaxies are enriched with heavier elements forged in stellar furnaces over multiple generations of stars.

DDO 68 is the best representation yet of a primordial galaxy in the local Universe as it appears at first glance to be very low in heavier elements — whose presence would be a sign of the existence of previous generations of stars.

Image credit: NASA & ESA; Acknowledgement: A. Aloisi (Space Telescope Science Institute)

(Source: spacetelescope.org)


Looking for comets in a sea of stars







On a July night this summer, a 5,200-pound balloon gondola hangs from a crane and moves toward the open doors of a building at the Johns Hopkins University Applied Physics Lab in Laurel, Md. The telescopes and instruments carried by the gondola, which are part of NASA’s Balloon Observation Platform for Planetary Science (BOPPS), are calibrated by taking a long look at the stars and other objects in the sky.
This photo was created from 100 separate 30-second-exposure photos, composited together to make the star trail that “spins” around Polaris, the North Star.
BOPPS is a high-altitude, stratospheric balloon mission, which will spend up to 24 hours aloft to study a number of objects in our solar system, including an Oort cloud comet. Two comets that may be visible during the flight include Pan STARRS and Siding Spring, which will pass very close to Mars on Oct. 19. The mission may also survey a potential array of other targets including asteroids Ceres and Vesta, Earth’s moon, and Neptune and Uranus. BOPPS is scheduled to launch on Sept. 25 from the NASA Columbia Scientific Balloon Research Facility in Fort Sumner, New Mexico.

Image credit: NASA/JHUAPL

Looking for comets in a sea of stars

On a July night this summer, a 5,200-pound balloon gondola hangs from a crane and moves toward the open doors of a building at the Johns Hopkins University Applied Physics Lab in Laurel, Md. The telescopes and instruments carried by the gondola, which are part of NASA’s Balloon Observation Platform for Planetary Science (BOPPS), are calibrated by taking a long look at the stars and other objects in the sky.

This photo was created from 100 separate 30-second-exposure photos, composited together to make the star trail that “spins” around Polaris, the North Star.

BOPPS is a high-altitude, stratospheric balloon mission, which will spend up to 24 hours aloft to study a number of objects in our solar system, including an Oort cloud comet. Two comets that may be visible during the flight include Pan STARRS and Siding Spring, which will pass very close to Mars on Oct. 19. The mission may also survey a potential array of other targets including asteroids Ceres and Vesta, Earth’s moon, and Neptune and Uranus. BOPPS is scheduled to launch on Sept. 25 from the NASA Columbia Scientific Balloon Research Facility in Fort Sumner, New Mexico.

Image credit: NASA/JHUAPL

(Source: nasa.gov)


Starry sky from the space station







One of the Expedition 41 crew members aboard the Earth-orbiting International Space Station on Sept. 13, 2014 captured this image of a starry sky. The white panel at left belonging to the ATV-5 spacecraft, which is docked with the orbital outpost, obstructs the view of Scorpius. The red star Antares is directly to the left of the bottom of the second ATV panel from the top. The two stars that are close together and on the lower left of the photo comprise Shaula, the tip of the scorpion’s tail. The open cluster close to Shaula is M7. A solar panel belonging to Russia’s service module or Zvezda runs along the right side of the bottom of the frame. 

Image credit: NASA

Starry sky from the space station

One of the Expedition 41 crew members aboard the Earth-orbiting International Space Station on Sept. 13, 2014 captured this image of a starry sky. The white panel at left belonging to the ATV-5 spacecraft, which is docked with the orbital outpost, obstructs the view of Scorpius. The red star Antares is directly to the left of the bottom of the second ATV panel from the top. The two stars that are close together and on the lower left of the photo comprise Shaula, the tip of the scorpion’s tail. The open cluster close to Shaula is M7. A solar panel belonging to Russia’s service module or Zvezda runs along the right side of the bottom of the frame. 

Image credit: NASA

(Source: nasa.gov)

NGC 206 and the star clouds of Andromeda

The large stellar association cataloged as NGC 206 is nestled within the dusty arms of the neighboring Andromeda galaxy. Also known as M31, the spiral galaxy is a mere 2.5 million light-years away. NGC 206 is near top center in this gorgeous close-up of the southwestern extent of Andromeda’s disk, a remarkable composite of data from space and ground-based observatories. The bright, blue stars of NGC 206 indicate its youth. In fact, its youngest massive stars are less than 10 million years old. Much larger than the open or galactic clusters of young stars in the disk of our Milky Way galaxy, NGC 206 spans about 4,000 light-years. That’s comparable in size to the giant stellar nurseries NGC 604 in nearby spiral M33 and the Tarantula Nebula, in the Large Magellanic Cloud. Star forming sites within Andromeda are revealed by the telltale reddish emission from clouds of ionized hydrogen gas.

Image credit and copyright: Subaru Telescope (NAOJ), Hubble Space Telescope, Local Group Galaxy Survey (Phil Massey, PI), Mayall 4-meter , Robert Gendler

NGC 206 and the star clouds of Andromeda

The large stellar association cataloged as NGC 206 is nestled within the dusty arms of the neighboring Andromeda galaxy. Also known as M31, the spiral galaxy is a mere 2.5 million light-years away. NGC 206 is near top center in this gorgeous close-up of the southwestern extent of Andromeda’s disk, a remarkable composite of data from space and ground-based observatories. The bright, blue stars of NGC 206 indicate its youth. In fact, its youngest massive stars are less than 10 million years old. Much larger than the open or galactic clusters of young stars in the disk of our Milky Way galaxy, NGC 206 spans about 4,000 light-years. That’s comparable in size to the giant stellar nurseries NGC 604 in nearby spiral M33 and the Tarantula Nebula, in the Large Magellanic Cloud. Star forming sites within Andromeda are revealed by the telltale reddish emission from clouds of ionized hydrogen gas.

Image credit and copyright: Subaru Telescope (NAOJ), 
Hubble Space Telescope, Local Group Galaxy Survey (Phil Massey, PI), Mayall 4-meter , Robert Gendler

(Source: apod.nasa.gov)

Clear skies on exo-Neptune



Astronomers using data from the NASA/ESA Hubble Space Telescope, the Spitzer Space Telescope, and the Kepler Space Telescope have discovered clear skies and steamy water vapour on a planet outside our Solar System. The planet, known as HAT-P-11b, is about the size of Neptune, making it the smallest exoplanet ever on which water vapour has been detected. The results will appear in the online version of the journal Nature on 24 September 2014.
The discovery is a milestone on the road to eventually finding molecules in the atmospheres of smaller, rocky planets more akin to Earth. Clouds in the atmospheres of planets can block the view of what lies beneath them. The molecular makeup of these lower regions can reveal important information about the composition and history of a planet. Finding clear skies on a Neptune-size planet is a good sign that some smaller planets might also have similarly good visibility.
"When astronomers go observing at night with telescopes, they say ‘clear skies’ to mean good luck," said Jonathan Fraine of the University of Maryland, USA, lead author of the study. "In this case, we found clear skies on a distant planet. That’s lucky for us because it means clouds didn’t block our view of water molecules."
HAT-P-11b is a so-called exo-Neptune — a Neptune-sized planet that orbits another star. It is located 120 light-years away in the constellation of Cygnus (The Swan). Unlike Neptune, this planet orbits closer to its star, making one lap roughly every five days. It is a warm world thought to have a rocky core, a mantle of fluid and ice, and a thick gaseous atmosphere. Not much else was known about the composition of the planet, or other exo-Neptunes like it, until now.
Part of the challenge in analysing the atmospheres of planets like this is their size. Larger Jupiter-like planets are easier to observe and researchers have already been able to detect water vapour in the atmospheres of some of these giant planets. Smaller planets are more difficult to probe — and all the smaller ones observed to date have appeared to be cloudy.
The team used Hubble’s Wide Field Camera 3 and a technique called transmission spectroscopy, in which a planet is observed as it crosses in front of its parent star. Starlight filters through the rim of the planet’s atmosphere and into the telescope. If molecules like water vapour are present, they absorb some of the starlight, leaving distinct signatures in the light that reaches our telescopes.
"We set out to look at the atmosphere of HAT-P-11b without knowing if its weather would be cloudy or not," said Nikku Madhusudhan, from the University of Cambridge, UK, part of the study team. "By using transmission spectroscopy, we could use Hubble to detect water vapour in the planet. This told us that the planet didn’t have thick clouds blocking the view and is a very hopeful sign that we can find and analyse more cloudless, smaller, planets in the future. It is groundbreaking!"
Before the team could celebrate they had to be sure that the water vapour was from the planet and not from cool starspots — “freckles” on the face of stars — on the parent star. Luckily, Kepler had been observing the patch of sky in which HAT-P-11b happens to lie for years. Those visible-light data were combined with targeted infraredSpitzer observations. By comparing the datasets the astronomers could confirm that the starspots were too hot to contain any water vapour, and so the vapour detected must belong to the planet.
The results from all three telescopes demonstrate that HAT-P-11b is blanketed in water vapour, hydrogen gas, and other yet-to-be-identified molecules. So in fact it is not only the smallest planet to have water vapour found in its atmosphere but is also the smallest planet for which molecules of any kind have been directly detected using spectroscopy.

Image credit: NASA/JPL-Caltech

Clear skies on exo-Neptune

Astronomers using data from the NASA/ESA Hubble Space Telescope, the Spitzer Space Telescope, and the Kepler Space Telescope have discovered clear skies and steamy water vapour on a planet outside our Solar System. The planet, known as HAT-P-11b, is about the size of Neptune, making it the smallest exoplanet ever on which water vapour has been detected. The results will appear in the online version of the journal Nature on 24 September 2014.

The discovery is a milestone on the road to eventually finding molecules in the atmospheres of smaller, rocky planets more akin to Earth. Clouds in the atmospheres of planets can block the view of what lies beneath them. The molecular makeup of these lower regions can reveal important information about the composition and history of a planet. Finding clear skies on a Neptune-size planet is a good sign that some smaller planets might also have similarly good visibility.

"When astronomers go observing at night with telescopes, they say ‘clear skies’ to mean good luck," said Jonathan Fraine of the University of Maryland, USA, lead author of the study. "In this case, we found clear skies on a distant planet. That’s lucky for us because it means clouds didn’t block our view of water molecules."

HAT-P-11b is a so-called exo-Neptune — a Neptune-sized planet that orbits another star. It is located 120 light-years away in the constellation of Cygnus (The Swan). Unlike Neptune, this planet orbits closer to its star, making one lap roughly every five days. It is a warm world thought to have a rocky core, a mantle of fluid and ice, and a thick gaseous atmosphere. Not much else was known about the composition of the planet, or other exo-Neptunes like it, until now.

Part of the challenge in analysing the atmospheres of planets like this is their size. Larger Jupiter-like planets are easier to observe and researchers have already been able to detect water vapour in the atmospheres of some of these giant planets. Smaller planets are more difficult to probe — and all the smaller ones observed to date have appeared to be cloudy.

The team used Hubble’s Wide Field Camera 3 and a technique called transmission spectroscopy, in which a planet is observed as it crosses in front of its parent star. Starlight filters through the rim of the planet’s atmosphere and into the telescope. If molecules like water vapour are present, they absorb some of the starlight, leaving distinct signatures in the light that reaches our telescopes.

"We set out to look at the atmosphere of HAT-P-11b without knowing if its weather would be cloudy or not," said Nikku Madhusudhan, from the University of Cambridge, UK, part of the study team. "By using transmission spectroscopy, we could use Hubble to detect water vapour in the planet. This told us that the planet didn’t have thick clouds blocking the view and is a very hopeful sign that we can find and analyse more cloudless, smaller, planets in the future. It is groundbreaking!"

Before the team could celebrate they had to be sure that the water vapour was from the planet and not from cool starspots — “freckles” on the face of stars — on the parent star. Luckily, Kepler had been observing the patch of sky in which HAT-P-11b happens to lie for years. Those visible-light data were combined with targeted infraredSpitzer observations. By comparing the datasets the astronomers could confirm that the starspots were too hot to contain any water vapour, and so the vapour detected must belong to the planet.

The results from all three telescopes demonstrate that HAT-P-11b is blanketed in water vapour, hydrogen gas, and other yet-to-be-identified molecules. So in fact it is not only the smallest planet to have water vapour found in its atmosphere but is also the smallest planet for which molecules of any kind have been directly detected using spectroscopy.

Image credit: NASA/JPL-Caltech

(Source: spacetelescope.org)

The Lagoon nebula in stars dust and gas

The large majestic Lagoon Nebula is home for many young stars and hot gas. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebula is so big and bright that it can be seen without a telescope toward the constellation of Sagittarius. Many bright stars are visible from NGC 6530, an open cluster that formed in the nebula only several million years ago. The greater nebula, also known as M8 and NGC 6523, is named “Lagoon” for the band of dust seen to the left of the open cluster’s center. A bright knot of gas and dust in the nebula’s center is known as the Hourglass Nebula. The featured picture is a newly processed panorama of M8, capturing five times the diameter of the Moon. Star formation continues in the Lagoon Nebula as witnessed by the many globules that exist there.

Image credit & copyright: Remus Chua (Celestial Portraits)

The Lagoon nebula in stars dust and gas

The large majestic Lagoon Nebula is home for many young stars and hot gas. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebula is so big and bright that it can be seen without a telescope toward the constellation of Sagittarius. Many bright stars are visible from NGC 6530, an open cluster that formed in the nebula only several million years ago. The greater nebula, also known as M8 and NGC 6523, is named “Lagoon” for the band of dust seen to the left of the open cluster’s center. A bright knot of gas and dust in the nebula’s center is known as the Hourglass Nebula. The featured picture is a newly processed panorama of M8, capturing five times the diameter of the Moon. Star formation continues in the Lagoon Nebula as witnessed by the many globules that exist there.

Image credit & copyright: Remus Chua (Celestial Portraits)

(Source: apod.nasa.gov)

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