Category Archives: ESA

Gaia’s Milky Way

gaia
Having examined and precisely measured the positions and brightness of over a BILLION stars, Gaia could well be the greatest mission nobody talks about.

Image: ESA

From ESA:

ESA’s Gaia is surveying stars in our Galaxy and local galactic neighbourhood in order to build the most precise 3D map of the Milky Way and answer questions about its structure, origin and evolution.

Launched in 2013, Gaia has already generated its first catalogue of more than a billion stars  – the largest all-sky survey of celestial objects to date.

To achieve its scientific aims, it points with ultra-high precision, and to enable the control team to monitor spacecraft performance, Gaia regularly reports to the ground information about its current attitude and the stars that have been observed.

These engineering data have been accumulated over 18 months and combined to create a ‘map’ of the observed star densities, from which a beautiful and ghostly virtual image of our magnificent Milky Way galaxy can be discerned, showing the attendant globular clusters and Magellanic clouds.

Where there are more stars, as in the Galactic centre, the map is brighter; where there are fewer, the map is darker. The map includes brightness data corresponding to several million stars.

More information on Gaia mission operations

Rosetta Archive

rosettafinal5a

The last of the NAVCAM images are now archived. The images in the latest  archive release are from the Rosetta’s last month of activity during the fantastic mission around Comet 67P/Churyumov-Gerasimenko.

This and other images can be found with the ESA Archive Image Browser

ESA’s description of the image above, one of the last five from Rosetta’s NAVCAM taken on 30 September 2016:

Single frame enhanced NavCam image taken on 29 September 2016 at 23:25 GMT, when Rosetta was 19.4 km from the centre of the nucleus of Comet 67P/Churyumov-Gerasimenko. The scale at the surface is about 1.7 m/pixel and the image measures about 1.7 km across.

Image (and description): ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

MRO Sees Schiaparelli

landingsitesc

Here’s an update from an earlier post.  Nice work from the HiRise camera on the Mar Reconnaissance Orbiter. You can see a larger version of the image above by clicking it. There is a larger version yet you can get from NASA which I recommend.

From NASA:

This Oct. 25, 2016, image shows the area where the European Space Agency’s Schiaparelli test lander reached the surface of Mars, with magnified insets of three sites where components of the spacecraft hit the ground. It is the first view of the site from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter taken after the Oct. 19, 2016, landing event.

The Schiaparelli test lander was one component of ESA’s ExoMars 2016 project, which placed the Trace Gas Orbiter into orbit around Mars on the same arrival date.

This HiRISE observation adds information to what was learned from observation of the same area on Oct. 20 by the Mars Reconnaissance Orbiter’s Context Camera (CTX). Of these two cameras, CTX covers more area and HiRISE shows more detail. A portion of the HiRISE field of view also provides color information. The impact scene was not within that portion for the Oct. 25 observation, but an observation with different pointing to add color and stereo information is planned.

This Oct. 25 observation shows three locations where hardware reached the ground, all within about 0.9 mile (1.5 kilometer) of each other, as expected. The annotated version includes insets with six-fold enlargement of each of those three areas. Brightness is adjusted separately for each inset to best show the details of that part of the scene. North is about 7 degrees counterclockwise from straight up. The scale bars are in meters.

At lower left is the parachute, adjacent to the back shell, which was its attachment point on the spacecraft. The parachute is much brighter than the Martian surface in this region. The smaller circular feature just south of the bright parachute is about the same size and shape as the back shell, (diameter of 7.9 feet or 2.4 meters).

At upper right are several bright features surrounded by dark radial impact patterns, located about where the heat shield was expected to impact. The bright spots may be part of the heat shield, such as insulation material, or gleaming reflections of the afternoon sunlight.

According to the ExoMars project, which received data from the spacecraft during its descent through the atmosphere, the heat shield separated as planned, the parachute deployed as planned but was released (with back shell) prematurely, and the lander hit the ground at a velocity of more than 180 miles per hour (more than 300 kilometers per hour).

At mid-upper left are markings left by the lander’s impact. The dark, approximately circular feature is about 7.9 feet (2.4 meters) in diameter, about the size of a shallow crater expected from impact into dry soil of an object with the lander’s mass — about 660 pounds (300 kilograms) — and calculated velocity. The resulting crater is estimated to be about a foot and a half (half a meter) deep. This first HiRISE observation does not show topography indicating the presence of a crater. Stereo information from combining this observation with a future one may provide a way to check. Surrounding the dark spot are dark radial patterns expected from an impact event. The dark curving line to the northeast of the dark spot is unusual for a typical impact event and not yet explained. Surrounding the dark spot are several relatively bright pixels or clusters of pixels. They could be image noise or real features, perhaps fragments of the lander. A later image is expected to confirm whether these spots are image noise or actual surface features.

Figure 1 is an unannotated version of the full scene, which covers an area about 0.9 mile (1.5 kilometers) wide. It is a portion of HiRISE observation ESP_048041_1780.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA’s Science Mission Directorate, Washington.

Image Credit:NASA/JPL-Caltech/Univ. of Arizona

 

Schiaparelli Found?

These “before and after” images from the Mars Reconnaissance Orbiter probably show Schiaparelli test lander. Initial reports show the thrusters did activate but failed at some point. We will know quite a lot more fairly soon. The decent data has been downlinked and is being studied. I am hearing reports the lander fell from 2 to 4 km; I thought the shield was supposed to separate at 7 km and the parachute was to be jettisoned and thrusters fired at just over 1 km, well below that reported altitude (link).

So we will wait and see.  Here’s the image description from NASA (with source image links):

This comparison of before-and-after images shows two spots that likely appeared in connection with the Oct. 19, 2016, Mars arrival of the European Space Agency’s Schiaparelli test lander.

The images were taken by the Context Camera (CTX) on NASA’s Mars Reconnaissance Orbiter on May 29, 2016, and Oct. 20, 2016.

The area indicated with a black outline is enlarged at right. The bright spot near the lower edge of the enlargement is interpreted as likely to be the lander’s parachute, which was deployed and then released during the descent through the Martian atmosphere. The larger dark spot near the upper edge of the enlargement was likely formed by the Schiaparelli lander. The spot is elliptical, about 50 by 130 feet (15 by 40 meters) in size, and is probably too large to have been made by the impact of the heat shield. The location information confirmed by this image will aid imaging the site with the High Resolution Imaging Science Experiment (HiRISE) camera, providing more details to use in interpretation. The main image covers an area about 2.5 miles (4 kilometers) wide, at about 2 degrees south latitude, 354 degrees east longitude, in the Meridiani Planum region of Mars. The scale bars are in meters. North is up. The before and after images are available separately as Figure A (from CTX observation J03_046129_1800) andFigure B (from CTX observation J08_047975_1779).

CTX was built by and is operated by Malin Space Science Systems, San Diego. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA’s Science Mission Directorate, Washington.

Image Credit: NASA/JPL-Caltech/MSSS

Hershel Looks at Orion

hershelcarbon

Click the image for the annotated version.

Credit: ESA/NASA/JPL-Caltech

The original caption:

The dusty side of the Sword of Orion is illuminated in this striking infrared image from the European Space Agency’s Hershel Space Observatory.

This immense nebula is the closest large region of star formation, situated about 1,500 light years away in the constellation of Orion. The parts that are easily observed in visible light, known alternatively as the Orion Nebula or Messier 42, correspond to the light blue regions. This is the glow from the warmest dust, illuminated by clusters of hot stars that have only recently been born in this chaotic region.

The red spine of material running from corner to corner reveals colder, denser filaments of dust and gas that are scattered throughout the Orion nebula. In visible light this would be a dark, opaque feature, hiding the reservoir of material from which stars have recently formed and will continue to form in the future.

Herschel data from the PACS instrument observations, at wavelengths of 100 and 160 microns, is displayed in blue and green, respectively, while SPIRE 250-micron data is shown in red.

Within the inset image, the emission from ionized carbon atoms (C+), overlaid in yellow, was isolated and mapped out from spectrographic data obtained by the HIFI instrument. A version without the inset is also available.

Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant as expected, scientists continue to analyze its data. NASA’s Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel’s three science instruments. The NASA Herschel Science Center, part of IPAC, supports the U.S. astronomical community. Caltech manages JPL for NASA.

Gaia’s First Map

gaiaskymap

The Gaia spacecraft gives us this view of our Milky Way. This map will improve in terms of artifact as Gaia makes more observations. Gaia will survey more than a BILLION stars by the time the mission ends. Gaia can determine stellar position so accurately it is estimated the spacecraft may find as many as 50,000 new planets by measuring the stellar wobble caused by an orbiting planet.

Copyright ESA/Gaia/DPAC

From ESA:
An all-sky view of stars in our Galaxy – the Milky Way – and neighbouring galaxies, based on the first year of observations from ESA’s Gaia satellite, from July 2014 to September 2015.

This map shows the density of stars observed by Gaia in each portion of the sky. Brighter regions indicate denser concentrations of stars, while darker regions correspond to patches of the sky where fewer stars are observed.

The Milky Way is a spiral galaxy, with most of its stars residing in a disc about 100 000 light-years across and about 1000 light-years thick. This structure is visible in the sky as the Galactic Plane – the brightest portion of this image –which runs horizontally and is especially bright at the centre.

Darker regions across the Galactic Plane correspond to dense clouds of interstellar gas and dust that absorb starlight along the line of sight.

Many globular and open clusters – groupings of stars held together by their mutual gravity – are also sprinkled across the image.

Globular clusters, large assemblies of hundreds of thousands to millions of old stars, are mainly found in the halo of the Milky Way, a roughly spherical structure with a radius of about 100 000 light-years, and so are visible across the image.

Open clusters are smaller assemblies of hundreds to thousands of stars and are found mainly in the Galactic Plane.

The two bright objects in the lower right of the image are the Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way. Other nearby galaxies are also visible, most notably Andromeda (also known as M31), the largest galactic neighbour to the Milky Way, in the lower left of the image. Below Andromeda is its satellite, the Triangulum galaxy (M33).

A number of artefacts are also visible on the image. These curved features and darker stripes are not of astronomical origin but rather reflect Gaia’s scanning procedure. As this map is based on observations performed during the mission’s first year, the survey is not yet uniform across the sky.

These artefacts will gradually disappear as more data are gathered during the five-year mission.

High resolution versions of the Gaia map, with transparent background, are available to download from:http://sci.esa.int/gaia/58209

Acknowledgement: A. Moitinho & M. Barros (CENTRA – University of Lisbon), on behalf of DPAC

Sentinel-1A Damaged

sentinel1a2

The power producing solar panels on the Sentinel-1A satellite have been damaged by an impact of some sort. The impacting object was tiny, in the few-millimetres class tiny. The image above from ESA shows the damage.

Even an impact with such a tiny object makes a difference:

A sudden small power reduction was observed in a solar array of Sentinel-1A, orbiting at 700 km altitude, at 17:07 GMT on 23 August. Slight changes in the orientation and the orbit of the satellite were also measured at the same time. — ESA

Sentinel 1A operations have not been impacted. There are in excess of 19,000 bits of known space debris, luckily this one was small.

The in-depth story from ESA.

A Mysterious Star

ESAyoungorold

This is very odd indeed. Almost wonder if there is an unseen companion.

From ESA:
At the centre of this image, captured by ESA’s Herschel space observatory, is a truly peculiar cosmic object: a star named IRAS 19312+1950.

Located over 12 000 light-years from us, this star has puzzled astronomers for many years because it shows conflicting signs of being both extremely old and extremely young.

Astronomers have spotted signs of emission usually associated with old, late-type stars: silicon oxide and hydroxyl masers – the microwave equivalent of a visible-light laser.

But they have also discovered characteristics mostly seen around early-type stars: a chemical-rich enveloping cloud usually seen around youthful stars and in regions of star formation.

Infrared observations from both Herschel and NASA’s Spitzer Space Telescope now suggest that it may instead be a star in the making, rather than a fully-fledged or ancient star. In other words, it is a protostar.

The star is about 10 times as massive as the Sun and emits about 20 000 times as much energy. It appears to be rich in oxygen, and has jets of gas streaming from both poles at speeds of at least 90 km/s.

In addition, it is surrounded and obscured by a collapsing cloud of gas, dust and ice – including large quantities of water and carbon dioxide ice – that contains an overall mass equivalent to 500 to 700 Suns.

Although it displays features atypical of its peers, astronomers believe it to be a stellar embryo fast approaching the end of its ‘accretion’ stage, the period in which it feeds upon surrounding material to fuel its growth. Although the region had not been pinpointed as a stellar nursery before, there are signs of recently formed and youthful stars nearby, supporting this idea.

This image is a composite of infrared data gathered by Herschel’s Photoconductor Array Camera and Spectrometer (PACS) at 70 (green) and 160 (blue) microns. The associated research is published in the Astrophysical Journal.

Image and caption: ESA/Herschel/PACS/Hi-GAL Project, KU Leuven

Polaris Flare

polarisflare

From ESA and the Planck Collaboration:

This image from ESA’s Planck satellite appears to show something quite ethereal and fantastical: a sprite-like figure emerging from scorching flames and walking towards the left of the frame, its silhouette a blaze of warm-hued colours.

This fiery illusion is actually a celestial feature named the Polaris Flare. This name is somewhat misleading; despite its moniker, the Polaris Flare is not a flare but a 10 light-year-wide bundle of dusty filaments in the constellation of Ursa Minor (The Little Bear), some 500 light-years away.

The Polaris Flare is located near the North Celestial Pole, a perceived point in the sky aligned with Earth’s spin axis. Extended into the skies of the northern and southern hemispheres, this imaginary line points to the two celestial poles. To find the North Celestial Pole, an observer need only locate the nearby Polaris (otherwise known as the North Star or Pole Star), the brightest star in the constellation of Ursa Minor.

Some of the secrets of the Polaris Flare were uncovered when it was observed by ESA’s Herschel some years ago. Using a combination of such Herschel observations and a computer simulation, scientists think that the Polaris Flare filaments could have been formed as a result of slow shockwaves pushing their way through a dense interstellar cloud, an accumulation of cold cosmic dust and gas sitting between the stars of our Galaxy.

These shockwaves, reminiscent of the sonic booms formed by fast sound waves here on Earth, would have been themselves triggered by nearby exploding stars that disrupted their surroundings as they died, triggering cloud-wide waves of turbulence

These shockwaves, reminiscent of the sonic booms formed by fast sound waves here on Earth, were themselves triggered by nearby exploding stars that disrupted their surroundings as they died, triggering cloud-wide waves of turbulence. These waves swept up the gas and dust in their path, sculpting the material into the snaking filaments we see.

This image is not a true-colour view, nor is it an artistic impression of the Flare, rather it comprises observations from Planck, which operated between 2009 and 2013. Planck scanned and mapped the entire sky, including the plane of the Milky Way, looking for signs of ancient light (known as the cosmic microwave background) and cosmic dust emission. This dust emission allowed Planck to create this unique map of the sky – a magnetic map.

The relief lines laced across this image show the average direction of our Galaxy’s magnetic field in the region containing the Polaris Flare. This was created using the observed emission from cosmic dust, which was polarised (constrained to one direction). Dust grains in and around the Milky Way are affected by and interlaced with the Galaxy’s magnetic field, causing them to align preferentially in space. This carries through to the dust’s emission, which also displays a preferential orientation that Planck could detect.

The emission from dust is computed from a combination of Planck observations at 353, 545 and 857 GHz, whereas the direction of the magnetic field is based on Planck polarisation data at 353 GHz. This frame has an area of 30 x 30º on the sky, and the colours represent the intensity of dust emission.

The Orbits of Rosetta

ESA gives us this visualization of Rosetta’s journey. The video gives us a pretty good sense of the journey and how exacting the planning was and what it will be in the future, although the final bits of the journey were not completely finalized until after this visualization was made.

The trajectory shown in this animation is created from real data, but the comet rotation is not. An arrow indicates the direction to the Sun as the camera viewpoint changes during the animation. — ESA

I am always am amazed how ESA can make the very difficult look easy.

Video