Pic of the Week: Grand Design Spiral Galaxy NGC 5643

Posted on by onespaceman2000
Image (Credit): Spiral galaxy NGC 5643, which is located roughly 40 million light-years away in the constellation Lupus. (ESA/Hubble & NASA, A. Riess, D. Thilker, D. De Martin (ESA/Hubble), M. Zamani (ESA/Hubble))

This week’s image comes from the NASA/European Space Agency’s (ESA) Hubble Space Telescope. It shows colorful spiral galaxy NGC 5643, which is located roughly 40 million light-years away in the constellation Lupus.

Here is more on the spiral galaxy from the ESA Hubble site:

NGC 5643 is what’s known as a grand design spiral, referring to how the galaxy’s two large, winding spiral arms are clear to see. The spiral arms are defined by bright blue stars, lacy reddish-brown dust clouds and pink star-forming regions. As fascinating as the galaxy appears at visible wavelengths, some of NGC 5643’s most interesting features are invisible to the human eye. Ultraviolet and X-ray images and spectra of NGC 5643 show that the galaxy hosts an active galactic nucleus: an especially bright galactic core powered by a feasting supermassive black hole. When a supermassive black hole ensnares gas from its surroundings, the gas collects in a disc that heats up to hundreds of thousands of degrees. The superheated gas shines brightly across the electromagnetic spectrum, but especially at X-ray wavelengths.

NGC 5643’s active galactic nucleus isn’t the brightest source of X-rays in the galaxy, though. Researchers using ESA’s XMM-Newton discovered an even brighter X-ray-emitting object, called NGC 5643 X-1, on the galaxy’s outskirts. What could be a more powerful source of X-rays than a supermassive black hole? Surprisingly, the answer appears to be a much smaller black hole!

While the exact identity of NGC 5643 X-1 is not yet known, evidence points to a black hole that is about 30 times more massive than the Sun. Locked in an orbital dance with a companion star, the black hole ensnares gas from its stellar companion, creating a superheated disc that outshines the galactic centre.

Pic of the Week: Collision in the Coma Galaxy Cluster

Posted on by onespaceman2000
Image (Credit): Interacting spiral galaxies called MCG+05-31-045 as captured by the Hubble Space Telescope. (ESA/Hubble & NASA, R. J. Foley (UC Santa Cruz))

This week’ image was captured by the Hubble Space Telescope. It captures the interplay between two galaxies in what is called MCG+05-31-045 that is part of the Coma galaxy cluster. These two galaxies are about 390 million light-years away.

Here is more on the image from NASA:

The Coma Cluster is a particularly rich cluster that contains over a thousand known galaxies. Amateur astronomers can easily spot several of these in a backyard telescope (See Caldwell 35). Most of them are elliptical galaxies, and that’s typical of a dense galaxy cluster like the Coma Cluster: many elliptical galaxies form through close encounters between galaxies that stir them up, or even collisions that rip them apart. While the stars in interacting galaxies can stay together, their gas is twisted and compressed by gravitational forces and rapidly used up to form new stars. When the hot, massive, blue stars die, there is little gas left to form new generations of young stars to replace them. As spiral galaxies interact, gravity disrupts the regular orbits that produce their striking spiral arms. Whether through mergers or simple near misses, the result is a galaxy almost devoid of gas, with aging stars orbiting in uncoordinated circles: an elliptical galaxy.

It’s very likely that a similar fate will befall MCG+05-31-045. As the smaller spiral galaxy is torn up and integrated into the larger galaxy, many new stars will form, and the hot, blue ones will quickly burn out, leaving cooler, redder stars behind in an elliptical galaxy, much like others in the Coma Cluster. But this process won’t be complete for many millions of years.

A Day in Astronomy: The Birth of Edwin Hubble

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Image (Credit): Edwin Hubble at the Mount Wilson Observatory in California. (Edwin P. Hubble Papers, Huntington Library, San Marino, California)

On this day in 1889, Edwin Powell Hubble was born in Marshfield, Missouri. He would go on to become an important astronomer who found that the “nebulae” in his time were actually galaxies far beyond our Milky Way. He also determined that the galaxies were moving away from one another, indicating an expanding universe. Of course, name is probably most recognizable to the pubic today as it relates to the Hubble Space Telescope.

Edwin Hubble knew he was part of long list of astronomers seeking answers about our universe when he said:

From our home on the Earth, we look out into the distances and strive to imagine the sort of world into which we were born. Today, we have reached far into space. Our immediate neighborhood we know rather intimately. But with increasing distance our knowledge fades … The search will continue. The urge is older than history. It is not satisfied and will not be suppressed.

You can read more about Edwin Hubble here.

Pic of the Week: Galaxies Passing in the Night

Posted on by onespaceman2000
Image (Credit): Galaxies IC 2163 and NGC 2207. (NASA, ESA, CSA, STScI)

This week’s image showing two galaxies – IC 2163 and NGC 2207 – comes from both the Hubble Space Telescope and the James Webb Space Telescope.

Here is more about the image from Hubblesite.org:

The gruesome palette of these galaxies is owed to a mix of mid-infrared light from NASA’s James Webb Space Telescope, and visible and ultraviolet light from NASA’s Hubble Space Telescope. The pair grazed one another millions of years ago. The smaller spiral on the left, cataloged as IC 2163, passed behind NGC 2207, the larger spiral galaxy at right.

Both have increased star formation rates. Combined, they are estimated to form the equivalent of two dozen new stars that are the size of the Sun annually. Our Milky Way galaxy forms the equivalent of two or three new Sun-like stars per year.

Both galaxies have hosted seven known supernovae, each of which may have cleared space in their arms, rearranging gas and dust that later cooled, and allowed new many stars to form. (Find these areas by looking for the bluest regions).

Pic of the Week: The Dance of R Aquarii

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Image (Credit): The R Aquarii binary star system. (NASA, ESA, Matthias Stute , Margarita Karovska , Davide De Martin (ESA/Hubble), Mahdi Zamani (ESA/Hubble))

This week’s image is from the Hubble Space Telescope. It shows a brilliant pattern in the sky about 700 light-years away. It is the product of an odd dance between two symbiotic stars, one red and the other white.

Here is more information about the image from the Hubblesite:

Located approximately 700 light-years away, a binary star system called R Aquarii undergoes violent eruptions that blast out huge filaments of glowing gas. The twisted stellar outflows make the region look like a lawn sprinkler gone berserk. This dramatically demonstrates how the universe redistributes the products of nuclear energy that form deep inside stars and jet back into space.

R Aquarii belongs to a class of double stars called symbiotic stars. The primary star is an aging red giant and its companion is a compact burned-out star known as a white dwarf. The red giant primary star is classified as a Mira variable that is over 400 times larger than our Sun. The bloated monster star pulsates, changes temperature, and varies in brightness by a factor of 750 times over a roughly 390-day period. At its peak the star is blinding at nearly 5,000 times our Sun’s brightness.

When the white dwarf star swings closest to the red giant along its 44-year orbital period, it gravitationally siphons off hydrogen gas. This material accumulates on the dwarf star’s surface until it undergoes spontaneous nuclear fusion, making that surface explode like a gigantic hydrogen bomb. After the outburst, the fueling cycle begins again.

This outburst ejects geyser-like filaments shooting out from the core, forming weird loops and trails as the plasma emerges in streamers. The plasma is twisted by the force of the explosion and channeled upwards and outwards by strong magnetic fields. The outflow appears to bend back on itself into a spiral pattern. The plasma is shooting into space over 1 million miles per hour – fast enough to travel from Earth to the Moon in 15 minutes! The filaments are glowing in visible light because they are energized by blistering radiation from the stellar duo.