Category Archives: Space Telescope

The Heart of the Crab


This image is a composite of separate exposures acquired by the ACS/WFC instrument using several filters. Coloration results from assigning different hues (colors) to the grayscale image associated with an individual filter.The assigned colors represent not only changes in different filters, but also the same filters taken on different exposure dates to highlight features that change over time.

Credit: ESA / NASA Acknowledgment: J. Hester (ASU) and M. Weisskopf (NASA/GSFC)

From Hubblesite:
At the center of the Crab Nebula, located in the constellation Taurus, lies a celestial “beating heart” that is an example of extreme physics in space. The tiny object blasts out blistering pulses of radiation 30 times a second with unbelievable clock-like precision. Astronomers soon figured out that it was the crushed core of an exploded star, called a neutron star, which wildly spins like a blender on puree. The burned-out stellar core can do this without flying apart because it is 10 billion times stronger than steel. This incredible density means that the mass of 1.4 suns has been crushed into a solid ball of neutrons no bigger than the width of a large city. This Hubble image captures the region around the neutron star. It is unleashing copious amounts of energy that are pushing on the expanding cloud of debris from the supernova explosion — like an animal rattling its cage. This includes wave-like tsunamis of charged particles embedded in deadly magnetic fields.

On July 4, 1054, Chinese astronomers recorded the supernova that formed the Crab Nebula. The ultimate celestial firework, this “guest star” was visible during the daytime for 23 days, shining six times brighter than the planet Venus. The supernova was also recorded by Japanese, Arabic, and Native American stargazers. While searching for a comet that was predicted to return in 1758, French astronomer Charles Messier discovered a hazy nebula in the direction of the long-vanished supernova. He would later add it to his celestial catalog as “Messier 1.” Because M1 didn’t move across the sky like a comet, Messier simply ignored it other than just marking it as a “fake comet.” Nearly a century later the British astronomer William Parsons sketched the nebula. Its resemblance to a crustacean led to M1’s other name, the Crab Nebula. In 1928 Edwin Hubble first proposed associating the Crab Nebula to the Chinese “guest star” of 1054.

Neptune Has a New Spot


Neptune has a new spot and thanks to Hubble we can see it. Click the image for the larger version.

From Hubble (via NASA):
New images obtained on May 16, 2016, by NASA’s Hubble Space Telescope confirm the presence of a dark vortex in the atmosphere of Neptune. Though similar features were seen during the Voyager 2 flyby of Neptune in 1989 and by the Hubble Space Telescope in 1994, this vortex is the first one observed on Neptune in the 21st century.

The discovery was announced on May 17, 2016, in a Central Bureau for Astronomical Telegrams (CBAT) electronic telegram by University of California at Berkeley research astronomer Mike Wong, who led the team that analyzed the Hubble data.

Neptune’s dark vortices are high-pressure systems and are usually accompanied by bright “companion clouds,” which are also now visible on the distant planet. The bright clouds form when the flow of ambient air is perturbed and diverted upward over the dark vortex, causing gases to likely freeze into methane ice crystals.

“Dark vortices coast through the atmosphere like huge, lens-shaped gaseous mountains,” Wong said. “And the companion clouds are similar to so-called orographic clouds that appear as pancake-shaped features lingering over mountains on Earth.”

Beginning in July 2015, bright clouds were again seen on Neptune by several observers, from amateurs to astronomers at the W. M. Keck Observatory in Hawaii. Astronomers suspected that these clouds might be bright companion clouds following an unseen dark vortex. Neptune’s dark vortices are typically only seen at blue wavelengths, and only Hubble has the high resolution required for seeing them on distant Neptune.

In September 2015, the Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble Space Telescope project that annually captures global maps of the outer planets, revealed a dark spot close to the location of the bright clouds, which had been tracked from the ground. By viewing the vortex a second time, the new Hubble images confirm that OPAL really detected a long-lived feature. The new data enabled the team to create a higher-quality map of the vortex and its surroundings.

Neptune’s dark vortices have exhibited surprising diversity over the years, in terms of size, shape, and stability (they meander in latitude, and sometimes speed up or slow down). They also come and go on much shorter timescales compared to similar anticyclones seen on Jupiter; large storms on Jupiter evolve over decades.

Planetary astronomers hope to better understand how dark vortices originate, what controls their drifts and oscillations, how they interact with the environment, and how they eventually dissipate, according to UC Berkeley doctoral student Joshua Tollefson, who was recently awarded a prestigious NASA Earth and Space Science Fellowship to study Neptune’s atmosphere. Measuring the evolution of the new dark vortex will extend knowledge of both the dark vortices themselves, as well as the structure and dynamics of the surrounding atmosphere.
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Looking Towards The Archer


From Hubble:
This colorful and star-studded view of the Milky Way galaxy was captured when the NASA/ESA Hubble Space Telescope pointed its cameras towards the constellation of Sagittarius (The Archer). Blue stars can be seen scattered across the frame, set against a distant backdrop of red-hued cosmic companions. This blue litter most likely formed at the same time from the same collapsing molecular cloud.

The color of a star can reveal many of its secrets. Shades of red indicate a star much cooler than the sun, so either at the end of its life, or much less massive. These lower-mass stars are called red dwarfs and are thought to be the most common type of star in the Milky Way. Similarly, brilliant blue hues indicate hot, young, or massive stars, many times the mass of the sun.

A star’s mass decides its fate; more massive stars burn brightly over a short lifespan, and die young after only tens of millions of years. Stars like the sun typically have more sedentary lifestyles and live longer, burning for approximately ten billion years. Smaller stars, on the other hand, live life in the slow lane and are predicted to exist for trillions of years, well beyond the current age of the universe.

Image credit: ESA/NASA
Text credit: European Space Agency

Hubble’s Hermet


From Hubble:

The drizzle of stars scattered across this image forms a galaxy known as UGC 4879. UGC 4879 is an irregular dwarf galaxy — as the name suggests, galaxies of this type are a little smaller and messier than their cosmic cousins, lacking the majestic swirl of a spiral or the coherence of an elliptical.

This galaxy is also very isolated. There are about 2.3 million light years between UGC 4879 and its closest neighbor, Leo A, which is about the same distance as that between the Andromeda Galaxy and the Milky Way.

This galaxy’s isolation means that it has not interacted with any surrounding galaxies, making it an ideal laboratory for studying star formation uncomplicated by interactions with other galaxies. Studies of UGC 4879 have revealed a significant amount of star formation in the first 4 billion years after the Big Bang, followed by a strange 9-billion-year lull in star formation that ended 1 billion years ago by a more recent re-ignition. The reason for this behavior, however, remains mysterious, and the solitary galaxy continues to provide ample study material for astronomers looking to understand the complex mysteries of star birth throughout the universe.

Image credit: NASA/ESA
Text credit: European Space Agency

New Hubble Image of Mars


A spectacular image of Mars from the Hubble taken on 12 May 2016 when Mars was reaching opposition.  Click the image for an annotated version.

The original caption:
This hemisphere of Mars contains landing sites for several NASA Mars surface robotic missions, including Viking 1 (1976), Mars Pathfinder (1997), and the still-operating Opportunity Mars rover. The landing sites of the Spirit and Curiosity Mars rovers are on the other side of the planet.

This observation was made just a few days before Mars opposition on May 22, when the sun and Mars will be on exact opposite sides of Earth, and when Mars will be at a distance of 47.4 million miles from Earth. On May 30, Mars will be the closest it has been to Earth in 11 years, at a distance of 46.8 million miles. Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth.

The biennial close approaches between Mars and Earth are not all the same. Mars’ orbit around the sun is markedly elliptical; the close approaches to Earth can range from 35 million to 63 million miles.

They occur because about every two years Earth’s orbit catches up to Mars’ orbit, aligning the sun, Earth, and Mars in a straight line, so that Mars and the sun are on “opposing” sides of Earth. This phenomenon is a result of the difference in orbital periods between Earth’s orbit and Mars’ orbit. While Earth takes the familiar 365 days to travel once around the sun, Mars takes 687 Earth days to make its trip around our star. As a result, Earth makes almost two full orbits in the time it takes Mars to make just one, resulting in the occurrence of Martian oppositions about every 26 months.

Credits: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute)

Hubble and Comet 252P


From Hubblesite:
This time-lapse movie, assembled from Hubble Space Telescope images, shows a narrow, well-defined jet of dust sweeping around with the rotation of Comet 252P/LINEAR like a spinning lawn sprinkler. The jet is illuminated by sunlight.

Researchers made the movie from Hubble images taken April 4, 2016, when the comet was 8.7 million miles from Earth. The time interval between each frame is approximately 30 to 50 minutes. The icy body made its closest approach to Earth on March 21, 2016, when it was 3.3 million miles away. It is now more than 25 million miles away from Earth.

The jet is composed of material from the comet’s icy nucleus that has been warmed by sunlight and ejected into space. The nucleus is too small for Hubble to resolve.

The jet’s changing direction is evidence that the comet’s nucleus is rotating, which makes the jet appear to spin like the water jet from a rotating lawn sprinkler. The movie underscores the dynamics and volatility of a comet’s fragile nucleus.

The movie is based on visible-light images taken with Hubble’s Wide Field Camera 3.

Credit: NASA, ESA, and J.-Y. Li (Planetary Science Institute)

UGC 477


There are a few different catalogs listing space objects.   UGC stands for Uppsala General Catalogue of Galaxies and is a catalog of galaxies to a limiting diameter of 1.0 arcminute and/or to a limiting apparent magnitude of 14.5 on the blue prints of the Palomar Observatory Sky Survey (POSS). Coverage is limited to the sky north of declination -02.5 degrees.

From Hubble (via NASA)

This striking NASA/ESA Hubble Space Telescope image captures the galaxy UGC 477, located just over 110 million light-years away in the constellation of Pisces (The Fish).

UGC 477 is a low surface brightness (LSB) galaxy. First proposed in 1976 by Mike Disney, the existence of LSB galaxies was confirmed only in 1986 with the discovery of Malin 1. LSB galaxies like UGC 477 are more diffusely distributed than galaxies such as Andromeda and the Milky Way. With surface brightnesses up to 250 times fainter than the night sky, these galaxies can be incredibly difficult to detect.

Most of the matter present in LSB galaxies is in the form of hydrogen gas, rather than stars. Unlike the bulges of normal spiral galaxies, the centers of LSB galaxies do not contain large numbers of stars. Astronomers suspect that this is because LSB galaxies are mainly found in regions devoid of other galaxies, and have therefore experienced fewer galactic interactions and mergers capable of triggering high rates of star formation.

LSB galaxies such as UGC 477 instead appear to be dominated by dark matter, making them excellent objects to study to further our understanding of this elusive substance. However, due to an underrepresentation in galactic surveys — caused by their characteristic low brightness — their importance has only been realized relatively recently.

Text credit: European Space Agency
Image credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

Hubble Finds A Moon

Peering to the outskirts of our solar system, NASA’s Hubble Space Telescope has spotted a small, dark moon orbiting Makemake, the second brightest icy dwarf planet — after Pluto — in the Kuiper Belt.

The moon — provisionally designated S/2015 (136472) 1 and nicknamed MK 2 — is more than 1,300 times fainter than Makemake. MK 2 was seen approximately 13,000 miles from the dwarf planet, and its diameter is estimated to be 100 miles across. Makemake is 870 miles wide. The dwarf planet, discovered in 2005, is named for a creation deity of the Rapa Nui people of Easter Island. NASA

Discovered by: Michael E. Brown, Chad Trujillo, and David Rabinowitz on 31 March 2005, MakeMake was at opposition in March and the magnitude was around 16.1.  Probably about as bright as it gets. To get an idea of magnitudes have a look at this page from the International Comet Quarterly.

Hubble’s Bubble


The Bubble Nebula is a great imaging target, very difficult (IMHO) to get just just right. I’ve yet to do it. This is an incredible image from Hubble is a composite of separate exposures acquired by the WFC3/UVIS instrument.

For the 26th anniversary of Hubble’s launch on April 24, 1990, the telescope has photographed an enormous, balloon-like bubble being blown into space by a super-hot, massive star. Astronomers trained the iconic telescope on this colorful feature, called the Bubble Nebula, or NGC 7635. The bubble is 7 light-years across — about one-and-a-half times the distance from our sun to its nearest stellar neighbor, Alpha Centauri. The Bubble Nebula lies 7,100 light-years from Earth in the constellation Cassiopeia. – Hubblesite

Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

NGC 2371 The One and Only


Hubble shows NGC 2371 and 2372 is actually just one object, one very large nebula.

From ESA:
Stars of different masses end their lives in different ways. While truly massive stars go out in a blaze of glory, intermediate-mass stars — those between roughly one and eight times the mass of the Sun — are somewhat quieter, forming cosmic objects known as planetary nebulas.

Named because of their vague resemblance to planets when seen through early, low-resolution telescopes, planetary nebulas are created when a dying star flings off its outer layers of gas into space. This cloud forms an expanding shell around the central star, while the star itself slowly cools to become a white dwarf. This is what has happened in this NASA/ESA Hubble Space Telescope image, taken in 2007, which shows a planetary nebula known as NGC 2371.

NGC 2371 resides 4300 light-years away from us, in the constellation of Gemini. It is one of the largest planetary nebulas known, measuring roughly three light-years across. Its progenitor star can be seen here as a pinprick of orange–-red light, surrounded by a green, blue and aqua-tinged puff of gas. This shell appears to have a regular, elliptical shape that is sliced in half by a dark lane running through the nebula, which also encompasses the central star.

This dark feature misled astronomers when NGC 2371 was initially catalogued because the two lobes visually resembled two objects, not one. As a result of this confusion, the nebula has two names in William Herschel’s New General Catalogue: NGC 2371 and 2372 (often combined as NGC 2371/2 or NGC 2371-2).

Two prominent pink patches are also visible on either side of the central star. These features are thought to be knots of gas, most likely jets, thrown off by the star at some point in the past. Their pink colour indicates that they are cooler and denser than their surroundings.

The nebula’s central star was once similar to the Sun, but is now only a shadow of its former self. It is slowly cooling after energetically shedding most of its gas, but has a long way to go yet. It currently boasts a scorching surface temperature of over 130 000ºC – some 25 times hotter than the surface of the Sun – and glows with the luminosity of at least 700 Suns.

The hot ultraviolet radiation streaming outwards into the nebula energises the gas it touches, causing NGC 2371 to glow in the beautiful aquamarine colours seen in this image.

This picture was taken in November 2007 by Hubble’s Wide Field Planetary Camera 2. It is a false-colour image created with a combination of filters to detect light coming from sulphur and nitrogen (shown in red), hydrogen (green) and oxygen (blue). The observations were gathered as part of the Hubble Heritage project.

This image was originally published on the Hubble Space Telescope website on 4 March 2008.

Credit:  NASA/ESA/Hubble Heritage Team (STScI/AURA)