Category Archives: Astronomy Picture of the Day
Hubble image of the Pulsar in the Crab Nebula
ABOUT THIS IMAGE:
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.
The neutron star is a showcase for extreme physical processes and unimaginable cosmic violence. Bright wisps are moving outward from the neutron star at half the speed of light to form an expanding ring. It is thought that these wisps originate from a shock wave that turns the high-speed wind from the neutron star into extremely energetic particles.
When this "heartbeat" radiation signature was first discovered in 1968, astronomers realized they had discovered a new type of astronomical object. Now astronomers know it's the archetype of a class of supernova remnants called pulsars — or rapidly spinning neutron stars. These interstellar "lighthouse beacons" are invaluable for doing observational experiments on a variety of astronomical phenomena, including measuring gravity waves.
Observations of the Crab supernova were recorded by Chinese astronomers in 1054 A.D. The nebula, bright enough to be visible in amateur telescopes, is located 6,500 light-years away in the constellation Taurus.
Posted on July 11, 2016 | Image
The Sombrero Galaxy-Astro Picture of the Day
Posted by DPS Bloggers
The Sombrero Galaxy (M-104):
The Sombrero Galaxy or Messier 104 or M-104 or NGC 4594 is a spiral galaxy located 28 million light-years from Earth. It can be located in the constellation Virgo . This galaxy looks like a Mexican Hat (Sombrero) and hence its name.
A galaxy is a system of stars, planets and stellar remnants which is massive and held together by gravity. It also has an interstellar medium of gas, dust, and dark matter (which is still not understood very well). Galaxies range from dwarfs have a few million stars to giants with one hundred trillion stars orbiting their galaxy's own center of mass. Supermassive black holes reside at the center of most galaxies. Galaxies have been categorised as elliptical galaxies (which are ellipse-shaped), Spiral galaxies which are disk-shaped with curving arm and irregular galaxies that have irregular shapes. Galaxies which are close together interact with each other , and may ultimately merge. Eg., Our galaxy the Milky way will merge with Andromeda galaxy. There are probably more than 170 billion galaxies in the observable universe. We will observe the Sombrero galaxy this winter through our 12″ telescope (however unlike this Hubble image it will appear just like a line smudged on a chalkboard) during the Astro-camps.
Source: Hubblesite.org
Posted in Astronomy Picture of the Day
The Cone Nebula-Astro Picture of the Day
The Cone Nebula (NGC-2264)
The Cone Nebula is found in the constellation of Monoceros and it is a stellar nursery (star forming region) where new stars are born. It is an interstellar cloud of dust, hydrogen, helium and other ionized gases. These and other materials come closer to each other due to gravity over millions of years to form larger masses, which attract further matter, and eventually they become massive enough to form stars. The core of these stars have temperatures of over 10 million °C. The remaining materials are then believed to form planets, and other planetary system objects. We had seen the Orion Nebula in the constellation of Orion last winter during the Astro-camp . Some of you were there when we captured a beautiful colour picture of the Orion Nebula using the DSLR attached to the Telescope. The colours are due to the various gases present in the Nebula.
In the case of the Cone nebula radiation from hot stars off the top of the gaseous pillar lights up the cone structure. It is about 2700 light years from earth.
The Crab Nebula – Astro Picture of the Day
The Crab Nebula-(also known as Messier-1 or M1)
The Crab Nebula is the left over structure from a Supernova explosion. So it is also known as a Supernova Remnant. A Supernova occurs when a big star (about 10 times the size of our Sun) dies by a violent explosion radiating energy as much as the Sun is expected to emit over its entire life span. A Supernova also leaves behind a neutron star which spins and emits pulses of radiation ranging from radio waves to gamma rays. This is known as a pulsar.
Chinese astronomers in 1054 were wondering about this bright star in the sky which was visible even during the day and lasted for over a month in the constellation of Taurus. Later is 1731 John Bevis an English Astronomer had observed and identified it. It is located about 6500 light years from the Earth and has an apparent magnitude of 8.4. In the centre of the nebula lies the Crab Pulsar, a neutron star 28–30 km across with a spin rate of 30.2 times per second, which emits radiation.
During the Astronomy Camp last winter many of you had seen the faint whitish clouds of this Supernova remnant through our 12″ telescope. However, this winter we are planning to image it with our new CCD Astro-Camera so that we can see the colours of this object which are not visible to the eye.,
The Cat's Eye Nebula
The Cat's Eye Nebula or NGC 6543, is a planetary nebula discovered by William Herschel on February 15, 1786. It is found in the constellation of Draco. A Planetary Nebula is formed when a smaller star (around the size of our Sun) dies forming a white dwarf (which is very dense) while the the outer layers of the star are expelled by strong stellar winds. There are around 3000 planetary nebulae known to exist in our galaxy, the Milky way, which has around 200 billion stars. They are rare and are found mostly near the plane of the Milky Way mainly near the galactic center.
The Hubble Space Telescope observations of the Cat's Eye nebula reveal very complex and interesting structural features. There is a bright and hot White Dwarf in the center of the Cat's Eye and around 1000 years ago this star lost its outer envelope, producing the nebula. Planetary nebulae are generally faint objects; none are visible to the naked eye.
The Globular Cluster-NGC 2808
NGC 2808 is a globular cluster in the constellation called Carina. A Globular cluster is a group of stars held very tightly by gravity, which gives them a spherical shape and high density at their centre. These are some of the oldest stars in our galaxy the Milky Way. Our galaxy has about 150 globular clusters. Those of you who have attended the Astronomy camps last winter may have observed two of the globular clusters: M-15 in the constellation Pegasus and M-63 in Hydra from DPS Tapi through our 12″ Dobsonian Telescope.
NGC 2808 is a massive globular cluster containing more than a million stars and is estimated to be 12.5-billion years old. Generally Globular clusters are made of only one generation of stars, this cluster is composed of three generations of stars all born within 200 million years of the formation of the cluster. It is predicted that that globular clusters contain some of the first stars produced in our galaxy but their origins are unclear.
The Horsehead Nebula:
The Horsehead Nebula is part of the Constellation called Orion (The Hunter). You can see the Orion constellation from DPS Tapi very clearly in winter (in fact it is very difficult to miss this constellation). A Nebula is a cloud of dust and gases where new stars are formed (a stellar nursery). The Horsehead Nebula is about 1500 light years from Earth. It is also known as Barnard 33 . The nebula is located just below the star Alnitak in Orion's belt. It is a part of the much larger Orion Molecular Cloud Complex. It's shape bears some resemblance to a horse's head when viewed from Earth. It is made of a swirling cloud of dark dust and gases. This stellar nursery contains over 100 known organic and inorganic gases as well as dust consisting of large and complex organic molecules. The red or pinkish glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. A glowing strip of hydrogen gas marks the edge of this cloud.
Astronomy Picture of the Day-M83
This is a Photo of the Southern Pinwheel Galaxy (also called as Messier 83 or M83 or NGC 5236) . It comes under the category of a barred spiral galaxy and is found in the constellation of Hydra. It is one of the brightest and closest barred spiral galaxies in the sky. Just about 15 million light years away!!?? It should be visible even with a pair of good binoculars but we are in the northern hemisphere and so it is a little difficult to find it since it stays low in the southern sky while viewing from our location.We'll still try identifying it this winter during our astro camps. What makes it more difficult is the light pollution in the southern sky in our city. I've been trying to observe this galaxy for the last two years with no success.
Six supernovae (SN 1923A, SN 1945B, SN 1950B, SN 1957D, SN 1968L and SN 1983N) have been observed in M83.
Spiral Galaxy M83