View allAll Photos Tagged HUBBLE
Située dans la constellation du Triangle (Triangulum) à 23 millions d'a.l. de la Voie lactée, la galaxie spirale barrée IC 1727 est actuellement en interaction avec son voisin proche NGC 672 (ici hors du cadre). Les interactions de la paire ont déclenché des phénomènes particuliers et intrigants au sein des deux objets, plus particulièrement dans IC 1727. La structure de la galaxie est visiblement tordue et asymétrique, son noyau lumineux ayant été traîné hors du centre. Les galaxies en interaction comme celles-ci ont souvent des signes de formation intense d’étoiles, épisodiques mais connus sous le nom de rafales d’étoiles, et renferment en conséquence des amas nouvellement formés. Ces rafales sont causées par la rotation gravitationnelle, la redistribution et le compactage du gaz et de la poussière. En fait, les explosions simultanées de formation d’étoiles se sont produites dans ces deux galaxies il y a 20-30 et 450-750 millions d’années (cf. site Hubble).
Pour situer l'astre dans sa constellation :
www.flickr.com/photos/7208148@N02/48830268511/in/datepost...
Dans la constellation de la Machine pneumatique (Antlia), à 55 millions d'a.l. de la Terre, la galaxie spirale intermédiaire NGC 2997 est particulièrement remarquable pour son noyau entouré d'une chaîne de nuages géants chauds d'hydrogène ionisé (cf. wikipédia, site Hubble).
Pour situer l'astre dans sa constellation :
www.flickr.com/photos/7208148@N02/48940906251/in/datepost...
The top portion of the Hubble Space Telescope is photographed some 350 miles above the Pacific Ocean southwest of Mexico, as the Space Shuttle Columbia was about to use its 50-foot-long robotic arm to lower the telescope into its cargo bay. The image is one of a series recorded with a digital still camera.
Credit: NASA
Note: I filled in some missing data in the middle in a way that may appear different from how I did it in the previous image.
Hubble Proposal ID: 11015
Chandra Data: Observation 776 - L2 Version 4
NASA/ESA/Hubble Team/Kevin M. Gill
Hubble Data PI: John Hughes
Chandra Observer (PI): Prof. John Hughes
Chandra Data Scientist: Jen Lauer
Blue (Chandra X-Ray): acisf00776N004_cntr_img2
Red (Subject): hst_11015_02_wfpc2_f656n_wf_drz
Red: hst_12326_01_wfc3_uvis_f814w_drz
Green: hst_12326_01_wfc3_uvis_f555w_drz
Blue: hst_12326_01_wfc3_uvis_f475w_drz
This new Hubble Space Telescope view of Jupiter, taken on June 27, 2019, reveals the giant planet's trademark Great Red Spot, and a more intense color palette in the clouds swirling in Jupiter's turbulent atmosphere than seen in previous years. The colors, and their changes, provide important clues to ongoing processes in Jupiter's atmosphere.
The bands are created by differences in the thickness and height of the ammonia ice clouds. The colorful bands, which flow in opposite directions at various latitudes, result from different atmospheric pressures. Lighter bands rise higher and have thicker clouds than the darker bands.
Among the most striking features in the image are the rich colors of the clouds moving toward the Great Red Spot, a storm rolling counterclockwise between two bands of clouds. These two cloud bands, above and below the Great Red Spot, are moving in opposite directions. The red band above and to the right (northeast) of the Great Red Spot contains clouds moving westward and around the north of the giant tempest. The white clouds to the left (southwest) of the storm are moving eastward to the south of the spot.
All of Jupiter's colorful cloud bands in this image are confined to the north and south by jet streams that remain constant, even when the bands change color. The bands are all separated by winds that can reach speeds of up to 400 miles (644 kilometers) per hour.
On the opposite side of the planet, the band of deep red color northeast of the Great Red Spot and the bright white band to the southeast of it become much fainter. The swirling filaments seen around the outer edge of the red super storm are high-altitude clouds that are being pulled in and around it.
The Great Red Spot is a towering structure shaped like a wedding cake, whose upper haze layer extends more than 3 miles (5 kilometers) higher than clouds in other areas. The gigantic structure, with a diameter slightly larger than Earth's, is a high-pressure wind system called an anticyclone that has been slowly downsizing since the 1800s. The reason for this change in size is still unknown.
A worm-shaped feature located below the Great Red Spot is a cyclone, a vortex around a low-pressure area with winds spinning in the opposite direction from the Red Spot. Researchers have observed cyclones with a wide variety of different appearances across the planet. The two white oval-shaped features are anticyclones, like small versions of the Great Red Spot.
Another interesting detail is the color of the wide band at the equator. The bright orange color may be a sign that deeper clouds are starting to clear out, emphasizing red particles in the overlying haze.
The new image was taken in visible light as part of the Outer Planets Atmospheres Legacy program, or OPAL. The program provides yearly Hubble global views of the outer planets to look for changes in their storms, winds and clouds.
Hubble's Wide Field Camera 3 observed Jupiter when the planet was 400 million miles from Earth, when Jupiter was near "opposition" or almost directly opposite the Sun in the sky.
Credits: NASA, ESA, A. Simon (Goddard Space Flight Center) and M.H. Wong (University of California, Berkeley)
For more information: www.nasa.gov/feature/goddard/2019/hubble-new-portrait-of-...
The Pencil Nebula
The Pencil Nebula: Remnants of an Exploded Star (NGC 2736)
Image Credit: NASA / Hubble Heritage
In celebration of the 25th anniversary of NASA's first space servicing mission to the Hubble Space Telescope, we are sharing this gallery of images from all five of the Hubble servicing missions.
Astronauts serviced Hubble for the first time in December 1993. Including that trip, there have been five astronaut servicing missions to Hubble between 1993 and 2009.
How did astronauts repair and service the Hubble Space Telescope more than 300 miles above the surface of the Earth? Watch Hubble astronauts as they discuss servicing from the innovative Robotics Operations Center: bit.ly/2EiiNTP
S125-E-007240 (14 May 2009) --- Astronaut Andrew Feustel, STS-125 mission specialist, appears to be selecting his next tool to use while participating in the first of his crew's five scheduled sessions of extravehicular activity to perform final hands-on servicing of the Hubble Space Telescope. Feustel and veteran astronaut John Grunsfeld (out of frame) are scheduled to participate in a total of three of those spacewalks.
Credit: NASA
NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.
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AUGUST 31, 2011: A team of scientists has collected enough high-resolution Hubble Space Telescope images over a 14-year period to stitch together time-lapse movies of powerful jets ejected from three young stars.
The jets, a byproduct of gas accretion around newly forming stars, shoot off at supersonic speeds in opposite directions through space. These phenomena are providing clues about the final stages of a star’s birth, offering a peek at how our Sun came into existence 4.5 billion years ago. Hubble’s unprecedented sharpness allows astronomers to see changes in the jets over just a few years’ time. Most astronomical processes change over timescales that are much longer than a human lifetime.
Caption: A long jet of material has burst out of a dark cloud of gas and dust that hides the newly formed star. The blue, fan-shaped region on the left is the edge of a cavity illuminated by the fledgling star. A massive clump of jet material collides with upstream gas, creating the white bow-shaped shock wave on the right.
To read more go to: www.nasa.gov/mission_pages/hubble/science/supersonic-jets...
Credit: NASA, ESA, P. Hartigan (Rice University), and G. Bacon (STScI)
NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.
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Not true color.
NASA/Hubble Team/GSFC/Keith Noll/Kevin M. Gill
Proposal ID: 11361
Red: hst_11361_01_wfpc2_f631n_pc_sci
Green: hst_11361_01_wfpc2_f588n_pc_sci
Blue: hst_11361_01_wfpc2_f410m_pc_sci
ARP 147 (also known as IC 298) is an interacting pair of ring galaxies. It lies 430 million to 440 million light years away in the constellation Cetus and does not appear to be part of any significant galaxy group. The system was originally discovered in 1893 by Stephane Javelle and is listed in the Atlas of Peculiar Galaxies.-Wiki
Link to Hubble website: hubblesite.org/newscenter/archive/releases/2008/37/image/a/
Data:
hlsp_heritage_hst_wfpc2_arp147_f450w_v1_sci_drz(Blue)
hlsp_heritage_hst_wfpc2_arp147_f555w_v1_sci_drz(green)
hlsp_heritage_hst_wfpc2_arp147_f814w_v1_sci_drz(Red)
Processed with FITS Liberator using a minimum linear stretch. CCDStack was used for DDP and Photoshop CS5 for color combine and post processing. I used Carboni’s tools to remove the banding that occurs in Hubble images. A high pass filter was applied to the LAB luminance channel to enhance detail.
NASA’s Hubble Space Telescope spacecraft was built by Lockheed Missiles Space Corporation (now Lockheed Martin) in its Sunnyvale, California facility. Since the 1990 launch, Lockheed Martin personnel located at NASA's Goddard Space Flight Center, have helped NASA manage the day-to-day spacecraft operations of the telescope, and provided preparation and training for the telescope’s many servicing missions.
A team of astronomers has taken the sharpest-ever picture of the unexpected interstellar comet 3I/ATLAS, using the crisp vision of the NASA/ESA Hubble Space Telescope.
ESA's Planetary Defence Office responded promptly to the discovery of the comet, and has been tracking it since the beginning of July.
Now, Hubble's observations from space are allowing astronomers to more accurately estimate the size of the comet’s solid icy nucleus. The upper limit on the diameter of the nucleus is 5.6 km, but it could be as small as 320 m across, researchers report.
Though the Hubble images put tighter constraints on the nucleus size compared to previous ground-based estimates, the solid heart of the comet presently cannot be directly seen, even by Hubble. Further observations, including by the NASA/ESA/CSA James Webb Space Telescope, will help refine our knowledge about the comet, including its chemical makeup.
Hubble also captured a dust plume ejected from the Sun-warmed side of the comet, and the hint of a dust tail streaming away from the nucleus. Hubble’s data show that the comet is losing dust in a similar manner to that from previously seen Sun-bound comets originating within our Solar System.
The big difference is that this interstellar visitor originated in some other stellar systems, elsewhere in our Milky Way galaxy.
3I/ATLAS is traveling through our Solar System at roughly 210 000 km per hour, the highest speed ever recorded for a Solar System visitor. This breathtaking sprint is evidence that the comet has been drifting through interstellar space for many billions of years. The gravitational slingshot effect from innumerable stars and nebulae the comet passed added momentum, ratcheting up its speed. The longer 3I/ATLAS was out in space, the higher its speed grew.
This comet was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on 1 July 2025 at a distance of 675 million km from the Sun. 3I/ATLAS should remain visible to ground-based telescopes until September, after which it will pass too close to the Sun to observe. It is expected to reappear on the other side of the Sun by early December.
Icy wanderers such as 3I/ATLAS offer a rare, tangible connection to the broader galaxy. To actually visit one would connect humankind with the Universe on a far greater scale. To this end, ESA is preparing the Comet Interceptor mission. The spacecraft will be launched in 2029 into a parking orbit, lying in wait for a suitable target – a pristine comet from the distant Oort Cloud that surrounds our Solar System, or, unlikely but highly appealing, an interstellar object.
While it is improbable that we will discover an interstellar object that is reachable for Comet Interceptor, as a first demonstration of a rapid response mission that waits in space for its target, it will be a pathfinder for possible future missions to intercept these mysterious visitors.
The research paper based on Hubble observations will be published in The Astrophysical Journal Letters.
[Image description: At the center of the image is a comet that appears as a teardrop-shaped bluish cocoon of dust coming off the comet’s solid, icy nucleus and seen against a black background. The comet appears to be heading to the bottom left corner of the image. About a dozen short, light blue diagonal streaks are seen scattered across the image, which are from background stars that appeared to move during the exposure because the telescope was tracking the moving comet.]
Credits:
NASA, ESA, D. Jewitt (UCLA), J. DePasquale (STScI); CC BY 4.0
The life of a planetary nebula is often chaotic, from the death of its parent star to the scattering of its contents far out into space. Captured here by the NASA/ESA Hubble Space Telescope, ESO 455-10 is one such planetary nebula, located in the constellation of Scorpius (The Scorpion).
The oblate shells of ESO 455-10, previously held tightly together as layers of its central star, not only give this planetary nebula its unique appearance, but also offer information about the nebula. Seen in a field of stars, the distinct asymmetrical arc of material over the north side of the nebula is a clear sign of interactions between ESO 455-10 and the interstellar medium.
The interstellar medium is the material such as diffuse gas between star systems and galaxies. The star at the center of ESO 455-10 allows Hubble to see the interaction with the gas and dust of the nebula, the surrounding interstellar medium, and the light from the star itself. Planetary nebulae are thought to be crucial in galactic enrichment as they distribute their elements, particularly the heavier metal elements produced inside a star, into the interstellar medium which will in time form the next generation of stars.
Text credit: European Space Agency (ESA)
Image credit: ESA/Hubble & NASA, L. Stanghellini
For more information: www.nasa.gov/image-feature/goddard/2021/hubble-spots-an-i...
Astronauts John M. Grunsfeld (right) and Richard M. Linnehan, STS-109 payload commander and mission specialist, respectively, are photographed near the Hubble Space Telescope (HST) temporarily parked in the Space Shuttle Columbia’s cargo bay at the close of the fifth and final day of extravehicular activities (EVAs). Their spacewalk centered around the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS), to install a Cryogenic Cooler and its Cooling System Radiator.
Credit: NASA
A team of astronomers using NASA’s Hubble Space Telescope reported the discovery of another moon orbiting the icy dwarf planet Pluto on this day in 2012. The discovery increased the number of known moons orbiting Pluto to five.
The team was using Hubble’s powerful vision to scour the Pluto system to uncover potential hazards to the New Horizons spacecraft. Moving past the dwarf planet at a speed of 30,000 miles per hour, New Horizons could have been destroyed in a collision with even a BB-shot-size piece of orbital debris.
Pluto’s largest moon, Charon, was discovered in 1978 in observations made at the United States Naval Observatory in Washington, D.C. Hubble observations in 2006 uncovered two additional small moons, Nix and Hydra. In 2011 another moon, P4, was found in Hubble data.
Provisionally designated S/2012 (134340) 1, the latest moon was detected in nine separate sets of images taken by Hubble’s Wide Field Camera 3 on June 26, 27, 29, and July 7 and 9.
Credit: NASA/ESA/M. Showalter (SETI Institute)
Image Number: ID 2012-32
Date: July 11, 2012
RGB process with 3 filters (435, 555 and 658) / crop
M51 taken by Hubble telescope
Credits : ESA / NASA / S. Beckwith (STScI) / Hubble Heritage Team
Processing: Thomas Thomopoulos
Here's a view of NGC 6946, aka the Fireworks Galaxy🎇, an intermediate spiral galaxy 25 million light-years away in the constellations Cepheus & Cygnus. This is a mosaic of 7 WFC3/UVIS observation sets from Jan. 25-26 2019, each containing 2 images in optical light and a synthesized green.
Principal Investigator for the observations was William P. Blair.
Image credit: NASA/ESA, STScI, and Jason Major.
Peering deep into the core of the Crab Nebula, this close-up image reveals the beating heart of one of the most historic and intensively studied remnants of a supernova, an exploding star. The inner region sends out clock-like pulses of radiation and tsunamis of charged particles embedded in magnetic fields.
The neutron star at the very center of the Crab Nebula has about the same mass as the sun but compressed into an incredibly dense sphere that is only a few miles across. Spinning 30 times a second, the neutron star shoots out detectable beams of energy that make it look like it's pulsating.
The NASA Hubble Space Telescope snapshot is centered on the region around the neutron star (the rightmost of the two bright stars near the center of this image) and the expanding, tattered, filamentary debris surrounding it. Hubble's sharp view captures the intricate details of glowing gas, shown in red, that forms a swirling medley of cavities and filaments. Inside this shell is a ghostly blue glow that is radiation given off by electrons spiraling at nearly the speed of light in the powerful magnetic field around the crushed stellar core.
Comparison of a Hubble Space Telescope image of Mars (taken in 1999) to my image of the same area April 16, 2014 with iPhone 4S through a NexStar 8SE telescope (stack of 5 best frames in Registax.)
© Dirk Delbaere 2023. All Rights Reserved
You need my written permission before using this image in any way. It is here only for viewing purposes.
backnext(at)gmail(dot)com
Sans la constellation du Toucan (Tucana), à 210 000 a.l. de la Terre, l'amas ouvert NGC 346 est entouré d'une structure spectaculaire de filaments arqués et déchiquetés avec une crête distincte. Un torrent de radiations provenant de ses étoiles chaudes se déploie en zones plus denses tout autour, créant une sorte de sculpture faite de poussière et de gaz. Vu en silhouette, le bord sombre et finement perlé de la crête contient plusieurs petits globules de poussière qui pointent vers l’amas central, comme des ventres pris dans un coup de vent (cf. site Hubble)
Pour situer l'astre dans sa constellation :
NGC 2261/Hubble's Variable Nebula is a variable nebula (apparently changes its appearance every few weeks) and the Cone Nebula is an H II region located in the constellation Monoceros and the Cone Nebula. An very heavy starfield is also located in this region thus making the work of processing to bring out features of both nebulae more challenging.
Explore Scientific ED102 FCD 100, ZWO ASI294MC PRO, Sky-Watcher HEQ5 PRO
12x300" (gain: 120.00) bin 1x1
Software: Photoshop CC 2019 · PixInsight
19x 240 sec RGB, Darks, Bias, Flats
Software:
Kstars/EKOS/INDI, Siril v0.9.11-rc1, GIMP
Hardware:
TS Photon 6" 154/600 F/4 Newton
GPU
Canon EOS 700Da
Hutech IDAS-LPS-D1
ASI 120MM mini on 8x50
HEQ-5
AstroPi (Ubuntu Mate + EKOS/INDI)
In this image the NASA/ESA Hubble Space Telescope has captured the smoking gun of a newborn star, the Herbig–Haro objects numbered 7 to 11 (HH 7–11). These five objects, visible in blue in the top centre of the image, lie within NGC 1333, a reflection nebula full of gas and dust found about a thousand light-years away from Earth.
Herbig-Haro objects like HH 7–11 are transient phenomena. Travelling away from the star that created them, at a speed of up to 250 000 kilometres per hour they disappear into nothingness within a few tens of thousands of years. The young star that is the source of HH 7-11 is called SVS 13 and all five objects are moving away from SVS 13 toward the upper left. The current distance between HH 7 and SVS 13 is about 20 000 times the distance between Earth and the Sun.
Herbig–Haro objects are formed when jets of ionised gas ejected by a young star collide with nearby clouds of gas and dust at high speeds. The Herbig-Haro objects visible in this image are no exception to this and were formed when the jets from the newborn star SVS 13 collided with the surrounding clouds. These collisions created the five brilliant clumps of light within the reflection nebula.
Credits: ESA/Hubble & NASA, K. Stapelfeldt; CC BY 4.0
A small section of the original 18Kx18K Hubble Heritage Orion Nebula image. hubblesite.org/newscenter/newsdesk/archive/releases/2006/01/
NGC 2623 is a merging pair of galaxies and lies 300 million light-years away in the constellation Cancer.
Hubble Legacy Archive Data set:
HST_9735_32_ACS_WFC_F435W_drz (Blue)
HST_9735_32_ACS_WFC_F555W_drz (Green)
HST_9735_32_ACS_WFC_F814W_drz (Red)
the blue compact dwarf galaxy NGC 5253, located in the constellation Centaurus around 11 million light-years from Earth. This new image combines data taken with Hubble’s Advanced Camera for Surveys (ACS), using its Wide Field Channel, and with the older Wide Field and Planetary Camera 2 (WFPC2). As a bonus for this Picture of the Week, there is also a second new image made using data from the High Resolution Channel (HRC) of ACS, a sub-instrument only operational for a few years that was optimised for detailed studies of environments dense with stars.
What has interested astronomers so much about this galaxy that three of Hubble’s instruments were used to study it in depth over ten years? It turns out to lie at the focus of a few areas of research where Hubble’s capabilities are essential. Dwarf galaxies are considered important for understanding the evolution of both stars and galaxies through time, since they resemble ancient, distant galaxies. NGC 5253 is called both a “starburst galaxy” and a “blue compact dwarf”: these names mean it is forming clusters of bright, massive stars at an exceptional rate. This Hubble image clearly shows the dense nebula which is being consumed to birth these stars, and which makes NGC 5253 a laboratory to investigate stellar composition, star formation and star clusters, all at once.
A tremendously high rate of star formation is a recipe for star clusters, but NGC 5253 goes beyond that: in a small region of the core, the star formation is so intense that the galaxy contains no less than three “super star clusters” (SSCs). SSCs are very bright, populous and massive open clusters which are believed to evolve into globular clusters. Globular clusters themselves offer unique insights into how stars form and evolve, but their origins are poorly understood. Astronomers were therefore eager to make use of the HRC sub-instrument, with its superb resolution, to hone in on these small, very dense clusters of stars.
[Image Description: An oval-shaped galaxy, made up of many point-like stars. It is softly lit from the centre, brightest and slightly blue at the very centre and fading to darkness at the edges. Surrounding the galaxy’s core are reddish clouds of gas and dust, most around or behind the core, but a few wisps are in front of it and block some light. Some faraway galaxies and two foreground stars can be seen around the galaxy.]
www.esa.int/ESA_Multimedia/Images/2024/06/Channelling_lig...
NGC 2903, a barred spiral galaxy located 30 million light-years away in Leo. My color-composite of Hubble observations made in visible and near-IR wavelengths on Jan. 9, 2021 (PI Janice Lee).
This galaxy is about the same size across as our Milky Way: around 100,000 light-years.
Here's a portion of the interior perimeter of the Helix Nebula, a planetary nebula 700 light-years away in the constellation Aquarius. This is a composite of image data acquired by Hubble's ACS/WFC instrument in Nov. 2002. It spans a distance about a quarter light-year. At the center of the nebula, located off frame to the upper left, is a low-mass star in the process of becoming a white dwarf. The colors come from gases in its outer layers that it has expelled and now glow due to ionization from its radiation. At the lower left are "cometary knots" of molecular gas that are being sculpted into long streamers by the central star's wind, with glowing ionized inward-facing fronts. The largest ones could fit our solar system out to the orbits of the planets.
“The Space Shuttle Discovery lifts off from Pad 39-B at 8:33 a.m. EDT, carrying a crew of five and the Hubble Space Telescope. STS-31 crew members are: Commander Loren Shriver; Pilot Charles Bolden; and Mission Specialists Steven Hawley, Bruce McCandless II, and Kathryn Sullivan.”
NASA image release June 3, 2010
These NASA Hubble Space Telescope snapshots reveal an impact scar on Jupiter fading from view over several months between July 2009 and November 2009.
To see a detail of the impact go to: www.flickr.com/photos/gsfc/4667118894
Credit: NASA, ESA, M. Wong, H. Hammel, I. de Pater, and the Jupiter Impact Team
To learn more go to: www.nasa.gov/mission_pages/hubble/science/jupiter-strike....
NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.
Processed using jpegs rather than the fits files.
Proposal ID: 15502
NASA/Hubble Team/OPAL/Kevin M. Gill
Red: F657N
Green: F547M
Blue: F467M
Luminance: F845M
La galaxie spirale barrée NGC 4394 (Hubble) se situe à 40 millions d'années-lumière de La Terre dans la constellation de la Chevelure de Bérénice (Coma Berenices) et fait partie de l'amas de la Vierge. Elle est l'archétype de la galaxie spirale barrée, avec des bras spiraux brillants émergeant des extrémités d'une barre qui traverse le renflement central de la galaxie. Ses bras sont parsemés de jeunes étoiles bleues, de filaments sombres de poussière cosmique et de régions lumineuses et nébuleuses de formation active d'étoiles. En son centre se trouve une région de gaz connue sous le nom de région de raies d'émission nucléaire à faible ionisation (LINER).
Les galaxies LINER sont des régions actives qui affichent un ensemble caractéristique de raies d’émission dans leur spectre, provenant principalement d’atomes d’oxygène, d’azote et de soufre faiblement ionisés. Bien que ces galaxies soient relativement courantes, nous ignorons toujours d’où vient l’énergie nécessaire à ioniser le gaz. Dans la plupart des cas, il peut s’agit de l’influence d’un trou noir au centre de la galaxie, mais cela pourrait aussi être le résultat d’un niveau élevé de formation d’étoiles.
Dans le cas de NGC 4394, l'interaction gravitationnelle avec un voisin proche a pu provoquer un écoulement de gaz dans la région centrale de la galaxie, fournissant ainsi un nouveau réservoir de matière pour alimenter le trou noir ou créer de nouvelles étoiles (cf. ESA/Hubble et NASA, remerciements à Judy Schmidt).
Pour situer la galaxie spirale barrée NGC 4394 (Hubble) dans la constellation de la Chevelure de Bérénice (Coma Berenices) :
This Picture of the Week shows a dwarf galaxy named UGC 685. Such galaxies are small and contain just a tiny fraction of the number of stars in a galaxy like the Milky Way. Dwarf galaxies often show a hazy structure, an ill-defined shape, and an appearance somewhat akin to a swarm or cloud of stars — and UGC 685 is no exception to this. Classified as an SAm galaxy — a type of unbarred spiral galaxy — it is located about 15 million light-years from Earth.
More information: www.spacetelescope.org/images/potw1935a/
Credit:
ESA/Hubble & NASA; the LEGUS team, B. Tully, D. Calzetti
Acknowledgement(s): Judy Schmidt (Geckzilla)
Imagine: an amazingly powerful version of the old-and-precious Hubble Space Telescope, a toy able to magnify what happens in those regions where a star is forming...would it look like this?
Imagine...
This is my first color-composite of a deep-sky object from Hubble observations. This is NGC 2525, a barred spiral galaxy 70 million light-years away. It's a little over half the size of the Milky Way.
Située dans la constellation de la Chevelure de Bérénice (Coma Berenices), la galaxie irrégulière naine NGC 4789 comprend des étoiles étalées à travers le ciel, dans un mélange apparemment désordonné et irrégulier, lui donnant une apparence plus subtile et plus abstraite que ses cousines spirales et elliptiques scintillantes. Celles-ci ont l’air d’avoir été saupoudrées au hasard dans le ciel, mais sont toutes maintenues ensemble par la gravité. Les couleurs de cette image ont été délibérément exagérées pour souligner le mélange d’étoiles bleues et rouges, les bleues étant brillantes, chaudes et massives, et formées relativement récemment, tandis que les rouges sont beaucoup plus anciennes (cf. site Hubble).
Pour situer l'astre dans sa constellation :
www.flickr.com/photos/7208148@N02/48775942151/in/datepost...