Category: Exploration


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© NASA
 
A huge planet is having quite the party in space, dancing between its cosmic companions rather eccentrically – all thanks to a tiny dwarf star which influences its bizarre movements. The new finding makes for a rather peculiar planetary system.

Measuring about eight times the mass of Jupiter, the enormous planet was discovered in 2011. At the time of its discovery, it was found to be orbiting a sun-like star called HD 4779 with high eccentricity. That is, its movements were far from perfectly circular – the further from a circle the trajectory is, the more eccentric it is.

But the eccentric orbit led a team made up almost entirely of current and former Carnegie scientists to speculate that something else may be influencing the monster planet’s movements. They tested that theory with the Magellan adaptive optics (MagAO) instrument suite, which allowed them to take extremely high-resolution images and gave them a sharper look at the night sky than ever before. Their speculation was then confirmed.

“At the telescope, we saw the object within seconds, and that told us it had to be a dwarf star,” said lead author Timothy Rodigas in a press release. The dwarf star was tiny, measuring at only 20 percent of the mass of our sun.

 

© Carnegie Institute

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NGC 7252: Hubble Captures Image of Atoms for Peace Galaxy

Dec 7, 2015 by Sergio Prostak

The NASA/ESA Hubble Space Telescope has produced this beautiful image of the inner parts of the distant galaxy NGC 7252.

This image shows the central regions of the peculiar galaxy NGC 7252. Image credit: NASA / ESA / Hubble / Judy Schmidt, www.geckzilla.com.

This image shows the central regions of the peculiar galaxy NGC 7252. Image credit: NASA / ESA / Hubble / Judy Schmidt, http://www.geckzilla.com.

NGC 7252, also known as LEDA 68612 or Arp 226, is a 12.7 magnitude peculiar galaxy in the constellation Aquarius.

It is about 212 million light-years distant and almost 200,000 light years across.

The galaxy has an odd nickname. In December 1953, President Eisenhower gave a speech that was dubbed Atoms for Peace.

The theme was promoting nuclear power for peaceful purposes – a particularly hot topic at the time.

This speech and the associated conference made waves in the scientific community and beyond to such an extent that NGC 7252 was named the Atoms for Peace galaxy.

This nickname is quite ironic, as the galaxy’s past was anything but peaceful.

Its peculiar appearance is the result of a collision between two similar gas-rich disc galaxies that took place about 600 million years ago, which ripped both galaxies apart.

The loop-like outer structures, likely made up of dust and stars flung outwards by the crash, but recalling orbiting electrons in an atom, are partly responsible for the galaxy’s nickname.

 

 

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Scientists get first glimpse of black hole eating star, ejecting high-speed flare

Date:
November 27, 2015
Source:
Johns Hopkins University
Summary:
An international team of astrophysicists has for the first time witnessed a star being swallowed by a black hole and ejecting a flare of matter moving at nearly the speed of light.

This artists impression shows a black hole consuming a star that has been torn apart by the black hole’s strong gravity. As a result of this massive “meal” the black hole begins to launch a powerful jet that we can detect with radio telescopes.
Credit: NASA/Goddard Space Flight Center/Swift

An international team of astrophysicists led by a Johns Hopkins University scientist has for the first time witnessed a star being swallowed by a black hole and ejecting a flare of matter moving at nearly the speed of light.

The finding reported in the journal Science tracks the star — about the size of our sun — as it shifts from its customary path, slips into the gravitational pull of a supermassive black hole and is sucked in, said Sjoert van Velzen, a Hubble fellow at Johns Hopkins.

“These events are extremely rare,” van Velzen said. “It’s the first time we see everything from the stellar destruction followed by the launch of a conical outflow, also called a jet, and we watched it unfold over several months.”

Black holes are areas of space so dense that irresistible gravitational force stops the escape of matter, gas and even light, rendering them invisible and creating the effect of a void in the fabric of space. Astrophysicists had predicted that when a black hole is force-fed a large amount of gas, in this case a whole star, then a fast-moving jet of plasma — elementary particles in a magnetic field — can escape from near the black hole rim, or “event horizon.” This study suggests this prediction was correct, the scientists said.

“Previous efforts to find evidence for these jets, including my own, were late to the game,” said van Velzen, who led the analysis and coordinated the efforts of 13 other scientists in the United States, the Netherlands, Great Britain and Australia.

Supermassive black holes, the largest of black holes, are believed to exist at the center of most massive galaxies. This particular one lies at the lighter end of the supermassive black hole spectrum, at only about a million times the mass of our sun, but still packing the force to gobble a star.

The first observation of the star being destroyed was made by a team at the Ohio State University, using an optical telescope in Hawaii. That team announced its discovery on Twitter in early December 2014.

After reading about the event, van Velzen contacted an astrophysics team led by Rob Fender at the University of Oxford in Great Britain. That group used radio telescopes to follow up as fast as possible. They were just in time to catch the action.

By the time it was done, the international team had data from satellites and ground-based telescopes that gathered X-ray, radio and optical signals, providing a stunning “multi-wavelength” portrait of this event.

It helped that the galaxy in question is closer to Earth than those studied previously in hopes of tracking a jet emerging after the destruction of a star. This galaxy is about 300 million light years away, while the others were at least three times farther away. One light year is 5.88 trillion miles.

The first step for the international team was to rule out the possibility that the light was from a pre-existing expansive swirling mass called an “accretion disk” that forms when a black hole is sucking in matter from space. That helped to confirm that the sudden increase of light from the galaxy was due to a newly trapped star.

“The destruction of a star by a black hole is beautifully complicated, and far from understood,” van Velzen said. “From our observations, we learn the streams of stellar debris can organize and make a jet rather quickly, which is valuable input for constructing a complete theory of these events.”

Van Velzen last year completed his doctoral dissertation at Radboud University in the Netherlands, where he studied jets from supermassive black holes. In the last line of the dissertation, he expressed his hope to discover these events within four years. It turned out to take only a few months after the ceremony for his dissertation defense.

Van Velzen and his team were not the only ones to hunt for radio signals from this particular unlucky star. A group at Harvard observed the same source with radio telescopes in New Mexico and announced its results online. Both teams presented results at a workshop in Jerusalem in early November. It was the first time the two competing teams had met face to face.

“The meeting was an intense, yet very productive exchange of ideas about this source,” van Velzen said. “We still get along very well; I actually went for a long hike near the Dead Sea with the leader of the competing group.”


Story Source:

The above post is reprinted from materials provided by Johns Hopkins University. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. van Velzen, G. E. Anderson, N. C. Stone, M. Fraser, T. Wevers, B. D. Metzger, P. G. Jonker, A. J. van der Horst, T. D. Staley, A. J. Mendez, J. C. A. Miller-Jones, S. T. Hodgkin, H. C. Campbell, R. P. Fender. A radio jet from the optical and X-ray bright stellar tidal disruption flare ASASSN-14li. Science, 2015; DOI: 10.1126/science.aad1182

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Comet fragments best explanation of mysterious dimming star

Date:
November 25, 2015
Source:
Iowa State University
Summary:
Astronomers have responded to the buzz about a mysterious dimming star by studying data from NASA’s Spitzer Space Telescope. They conclude the dimming was probably caused by a family of comets passing in front of the star.

This illustration shows a star behind a shattered comet. Observations of the star KIC 8462852 by NASA’s Kepler and Spitzer space telescopes suggest that its unusual light signals are likely from dusty comet fragments, which blocked the light of the star as they passed in front of it in 2011 and 2013. The comets are thought to be traveling around the star in a very long, eccentric orbit.
Credit: Illustration by NASA/JPL-Caltech

Was it a catastrophic collision in the star’s asteroid belt? A giant impact that disrupted a nearby planet? A dusty cloud of rock and debris? A family of comets breaking apart? Or was it alien megastructures built to harvest the star’s energy?

Just what caused the mysterious dimming of star KIC 8462852?

Massimo Marengo, an Iowa State University associate professor of physics and astronomy, wondered when he saw all the buzz about the mysterious star found by citizen scientists on the Planet Hunters website.

Those citizen scientists were highlighting measurements of star brightness recorded by NASA’s Kepler spacecraft. Tiny dips in a star’s brightness can indicate a planet is passing in front of the star. That’s how Kepler astronomers — and citizen scientists using the internet to help analyze the light curves of stars — are looking for planets.

But this star had deep dips in brightness — up to 22 percent. The star’s brightness also changed irregularly, sometimes for days and even months at a time. A search of the 150,000-plus stars in Kepler’s database found nothing like this.

So Marengo and two other astronomers decided to take a close look at the star using data taken with the Infrared Array Camera of NASA’s Spitzer Space Telescope. They report their findings in a paper recently published online by The Astrophysical Journal Letters.

Their conclusion?

“The scenario in which the dimming in the KIC 8462852 light curve were caused by the destruction of a family of comets remains the preferred explanation …,” wrote the three — Marengo; Alan Hulsebus, an Iowa State doctoral student; and Sarah Willis, a former Iowa State graduate student now with the Massachusetts Institute of Technology’s Lincoln Laboratory.

Questions about the star were launched last month when a research team led by Tabetha Boyajian of Yale University reported on the star in the Monthly Notices of the Royal Astronomical Society. The astronomers reported how citizen scientists tagged the star’s deep and irregular dips in brightness as “bizarre” and “interesting.”

Boyajian and the other researchers looked at the data and investigated several possible causes. They wrote the “most promising theory” was a barrage of crumbling comets passing in front of the star.

In a subsequent paper submitted to The Astrophysical Journal, Jason Wright and colleagues at Penn State University speculated about other causes, including alien megastructures built to harvest energy while orbiting the star.

When the Iowa State astronomers studied the star with Spitzer infrared data from January 2015 — two years after the Kepler measurements — Marengo said they didn’t see much. If there had been some kind of catastrophe near the star, he said there would be a lot of dust and debris. And that would show up as extra infrared emissions.

Marengo said the study looked at two different infrared wavelengths: the shorter was consistent with a typical star and the longer showed some infrared emissions, but not enough to reach a detection threshold. The astronomers concluded there were no excess infrared emissions and therefore no sign of an asteroid belt collision, a giant impact on a planet or a dusty cloud of rock and debris.

So Marengo and his colleagues say the destruction of a family of comets near the star is the most likely explanation for the mysterious dimming. The comet fragments coming in rapidly at a steep, elliptical orbit could create a big debris cloud that could dim the star. Then the cloud would move off, restoring the star’s brightness and leaving no trace of excess infrared light.

And the alien megastructure theory?

“We didn’t look for that,” Marengo said. “We can’t really say it is, or is not. But what the star is doing is very strange. It’s interesting when you have phenomena like that — typically it means there’s some new physical explanation or a new concept to be discovered.”


Story Source:

The above post is reprinted from materials provided by Iowa State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Massimo Marengo, Alan Hulsebus, Sarah Willis. KIC 8462852: THE INFRARED FLUX. The Astrophysical Journal, 2015; 814 (1): L15 DOI: 10.1088/2041-8205/814/1/L15

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Mars to get planetary ring set to rival Saturn, with moon Phobos set to break up from tidal stress

Updated Mon at 2:50pm

Mars is destined to get a spectacular new planetary ring system to rival that of Saturn, but don’t hold your breath because it will not be for another 30 million years or so, according to scientists.

The findings, published in the journal Nature Geoscience, are based on a new study to determine the fate destined to befall the diminutive Martian moon Phobos.

Over time Phobos is creeping inwards towards Mars at a couple of centimetres per year.

Dr Benjamin Black

“We found that Phobos is too weak to withstand tidal stresses from Mars and we expect it to break apart in a few tens of millions of years and form a ring around Mars,” the study’s lead author Dr Benjamin Black of the University of California said.

Only the giant planets of the outer solar system have rings at the moment.

Phobos — the larger of the two moons circling Mars — orbits just 6,000 kilometres above the surface of the red planet, closer than any other moon in the solar system.

“Over time Phobos is creeping inwards towards Mars at a couple of centimetres per year,” Dr Black said.

“We wanted to figure out whether Phobos crashes into Mars or breaks apart to form a ring, so we needed to know how strong it was — is it going to be able to stand the increasing tidal stresses that are going to be pulling this little moon apart, or will it eventually succumb to these forces?”

Dr Black and co-author Tushar Mittal found that Phobos will be pulled apart by the red planet’s gravitational tidal forces in about 20 to 40 million years’ time.

“We concluded that Phobos would break apart between 2.4 and about 1.1 Mars radii, somewhere between 8,500 kilometres down to around 4,000 kilometres or so,” Dr Black said.

 

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Discovery News

This Massive Exoplanet Is Being Born Right Now

//

 

The baby planet circles a very young, sun-like star located in a giant cloud of molecular gas 430 light-years from Earth in the constellation Taurus.

PHOTOS: The Most Horrific Alien Planets In Our Galaxy

Astronomers had previously noted a hefty gap in the disk of gas and dust surrounding the star, known as LkCa 15. They suspected the gravitational pull of an evolving planet had cleared out an orbital zone, similar to how some moons circling Saturn create gaps in its rings.

Now, a new series of observations adds key details of the planet-in-the-making, showing for the first time how it is feeding on hydrogen gas.

“This discovery has far-reaching implications for our understanding of the planet-forming process and of the properties of young planets,” Princeton University astrophysicist Zhaohuan Zhu wrote in a commentary in this week’s Nature.

 

 

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For the first time, astronomers have directly observed a planet in the making.

Play Video
Earth is in what’s called the habitable zone. It’s far enough from the sun that it doesn’t get fried, and close enough that it gets the best of its warmth. We like to think we’re special for this, but it turns out we might be pretty run of the mill.

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Science News

News

 

By
5:54pm, November 9, 2015

OUT-OF-THIS-WORLD LANDSCAPE The latest data from the New Horizons mission has helped create topographical maps of Pluto (blue shows lower elevations, brown, higher elevations) that have revealed surprises such as these two possible ice volcanoes, the first of their kind in the outer solar system.

 

OXON HILL, Md. — At this point, the only thing unsurprising about Pluto is that it continues to offer up surprises.

 

A wide variety of landscapes, ongoing surface transformations and a family of wildly spinning moons are among the riddles reported by the New Horizons mission team November 9 at a meeting of the American Astronomical Society’s Division for Planetary Sciences.

 

“Pluto is like a graduate course in planetary science,” mission leader Alan Stern said at a news briefing. “It’s going to take the larger planetary science community many years to digest all this.”

 

The New Horizons spacecraft, which buzzed the dwarf planet on July 14, has so far sent back only about 20 percent of the data it acquired from the Pluto system. And every new nugget continues a story that’s pretty familiar by now: Pluto is a weird place.

 

Terrains both new and old sit side-by-side on Pluto’s surface. Some heavily cratered regions are roughly 4 billion years old, about as old as Pluto itself. Others, like the now famous heart, appear to have been laid down within the last 10 million years, judging by the total lack of craters.

 

 

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Eaten away by ‘vog’: Acid fog eroding rocks on Mars

The planet Mars showing showing Terra Meridiani is seen in an undated NASA image. © Greg Shirah
Scientists believe they have figured out why rocks on Mars are eroding. They say an acidic fog created by volcanic eruptions on the red planet is the probable culprit.

Planetary scientist Shoshanna Cole came up with the theory after studying a 100-acre area on Husband Hill in the Columbia Hills of the Gusev Crater on Mars using data gathered by a number of instruments on the 2003 Mars Exploration Rover Spirit.

She found that acidic vapors released by eruptions may have been responsible for eating away rocks on the Watchtower Class outcrops on the Cumberland Ridge and Husband Hill summit.

View image on Twitter

Acid fog corroded the surface of Mars: a new discovery from NASA’s long-dead Spirit rover. http://bit.ly/1H6jT0V 

“The special thing about Watchtower Class is that it’s very widespread and we see it in different locations. As far as we can tell, it is part of the ground there,” which means that these rocks record environments that existed on Mars billions of years ago, Cole said in a press release submitted by the Geological Society of America.

 

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Space Weather.com

by Dr. Tony Phillips.

All Sky Fireball Network

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA’s Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth’s atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

On Apr. 25, 2014, the network reported 9 fireballs.
(9 sporadics)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

On Apr. 24, 2014, the network reported 19 fireballs.
(15 sporadics, 4 April Lyrids)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

On April 26, 2014 there were 1466 potentially hazardous asteroids.

Recent & Upcoming Earth-asteroid encounters:

Asteroid
Date(UT)
Miss Distance
Size
2014 GG49
Apr 19
3.9 LD
31 m
2014 HP2
Apr 24
3.8 LD
15 m
2014 HU2
Apr 25
3.7 LD
22 m
2014 HM4
Apr 25
1.6 LD
18 m
2014 HW
Apr 27
2.1 LD
10 m
2007 HB15
Apr 28
6.7 LD
12 m
2014 HL2
Apr 28
8.8 LD
26 m
2014 HV2
Apr 29
1.4 LD
33 m
2010 JO33
May 17
4 LD
43 m
2005 UK1
May 20
36.7 LD
1.1 km
1997 WS22
May 21
47.1 LD
1.5 km
2002 JC
May 24
48.7 LD
1.4 km

Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.

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