Huge Alien Planet Forcing Host Star Age Prematurely

A nearby star is not acting its age, thanks to the influence of a massive exoplanet.

The close-orbiting alien planet, known as WASP-18b, is apparently disrupting the magnetic field of its host star so much that the object is behaving like a much older star, researchers said.

"WASP-18b is an extreme exoplanet," study lead author Ignazio Pillitteri, of the Instituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Palermo in Italy, said in a statement.

"It is one of the most massive hot Jupiters known and one of the closest to its host star, and these characteristics lead to unexpected behaviour. The planet is causing its host star to act old before its time."

Artist's concept depicting the giant alien planet WASP-18b and its star, which are about 330 light-years away. 

Credit: NASA/CXC/M. Weiss

The star WASP-18, which lies about 330 light-years away, is about as massive as our own sun.

The gas giant WASP-18b weighs in at more than 10 times the mass of Jupiter and completes one orbit around the star in less than 23 hours, leading scientists to classify it as a "hot Jupiter."

WASP-18b's tight orbit has led scientists to estimate that it may have only one million years of life or so remaining before it's destroyed by the parent star.

Pillitteri's team targeted WASP-18 with NASA's Chandra X-ray Observatory and found it to be relatively quiet, a characteristic of older stars.

Young stars tend to be more active, with stronger magnetic fields, larger flares and more intense X-ray emission.

Stellar activity is connected to rotation, a process that slows with age.

Observations of WASP-18 using Chandra revealed no X-ray emission.

This by itself would suggest that the star has an age similar to the sun's 5 billion years, researchers said.

However, Pillitteri and his team used other data as well as theoretical models to calculate that WASP-18 is actually just 500 million to 2 billion years old, and thus approximately 100 times less active than a star its age should be.

"We think the planet is aging the star by wreaking havoc on its innards," said co-author Scott Wolk, of the Harvard-Smithsonian Center for Astrophysics (CfA) in Massachusetts.

WASP-18b's strong gravitational pull may be disrupting the star's magnetic field, researchers said.

The planet's tug exerts forces similar to those imposed on Earth's tides by the moon, but on a much larger scale.

Forceful neighbours cause stellar twins to diverge

Cosmic twins the Luminous Blue Variable Nebula LBV3 (top row) and the Pistol Nebula (bottom row) display how even large objects in the universe can be affected neighbourly influences. 

The left images were taken by the Faint Object InfraRed Camera (FORCAST) on NASA’s airborne SOFIA Telescope. 

The right images of each nebula were taken by a near-infrared spectrometer on the Hubble Space Telescope.

Much like an environment influences people, so too do cosmic communities affect even giant dazzling stars: Peering deep into the Milky Way galaxy's center from a high-flying observatory, Cornell astronomers have discovered identical, rare stars whose diverging dusty and gaseous garb are strictly influenced by an intrusive cluster of neighbours.

Scarce, short-lived, hyperbright stars called luminous blue variables – a million times brighter than our own sun – inhabit the center of the Milky Way galaxy, 25,000 light years from Earth, which loiters in the Milky Way boonies.

FORCAST team on NASA’s airborne SOFIA Telescope

Astronomers have found two luminous blue variable (LBV) stars – one called the Pistol star and the other named LBV3 – to be identical.

As stars, they are themselves neighbors, but their dusty, gaseous outer cloaks (outer nebulae) are substantially different.

Both are the same size and have identical gas-to-dust mass ratios and total gas masses, according to a paper published April 2 in the Astrophysical Journal.

"Think identical stars with different shells. We found that the nebula of the insanely bright Pistol star is warped, while the LBV3 is an almost-perfect spherical shell," says Ryan M. Lau, Cornell doctoral candidate in the field of astronomy.

"These LBVs are rare stars, and we only know about 12 that exist, but they are surrounded by these dust- and gas-filled nebulae that look different."

Both the Pistol star and LBV3 formed under similar conditions, according to the researchers. Dust in the Pistol star's nebula is brilliant, compressed, externally heated and ionized, thanks to its proximity to neighbors in the Quintuplet Cluster.

By contrast, the LBV3 nebula is dim, symmetrical and cooler. LBV3's nebula progresses in an outward fashion naturally, thanks to its relative lack of proximity to anything.

"The initial attention draw to the Pistol star was its high luminosity, [but] the nebulae around it and its sister star [LBV3] have turned out to be quite interesting."

"While the Pistol star is a member of the Quintuplet Cluster – although on the outskirts of the cluster – it is about six light-years away from the cluster's center."

"That's about 1.5 times the distance from our solar system to the nearest star," says senior author Terry Herter, Cornell professor of astronomy and department chair.

"It's impressive that even at this distance, the rest of the Quintuplet Cluster exerts a large influence on the Pistol nebula."

In optical ground telescopes, cosmic dust obfuscates both stars. To cut through the cosmic grime, astronomers need a midrange infrared telescope.

To explore far above atmospheric waters, the astronomers examined the inner galaxy July 1, 2013, from SOFIA (the Stratospheric Observatory for Infrared Astronomy), a modified Boeing 747 SP that climbs to 43,000 feet.

To spy these super luminous objects, the group used FORCAST, the Faint Object InfraRed Camera for the SOFIA Telescope, developed at Cornell.

More information: "Nature Versus Nurture: Luminous Blue Variable Nebulae in and near Massive Stellar Clusters at the Galactic Center." Ryan M. Lau, Terry L. Herter, Mark R. Morris, Joseph D. Adams. arXiv:1403.5298 [astro-ph.GA] arxiv.org/abs/1403.5298

NASA: Boeing Supersonic Model Points to Fast Future

If human beings are ever to fly faster than the speed of sound from one side of the country to another, we first have to figure out how to reduce the level of sonic boom generated by supersonic flight.

Earlier this fall, a subscale model of a potential future low-boom supersonic aircraft designed by The Boeing Company was installed for testing in the supersonic wind tunnel at NASA's Glenn Research Center in Cleveland.

This model is a larger of two models used in the test.

The model contains a force measurement balance used to capture force measurements (lift, drag).

Depending on the type of test and on the tunnel, the model can be oriented any way. The picture model is actually upside down.

Another smaller model was used to capture measurements of the off-body pressures that create a sonic boom.

The tests are among those being conducted by NASA and its partners to identify technologies and designs to achieve a level of sonic boom so low that it barely registers on buildings and people below.

Image Credit: NASA/Michelle M. Murphy