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Category Archives: exoplanets

Puffed-up hot Jupiters may be getting an electric charge

Some hot Jupiters orbit so close to their host stars that their atmospheres are boiling off.
NASA

One of the neat things about the huge catalog of extrasolar planets we now have is that they're revealing problems we never knew we had. Previously with only one solar system to look at, it was possible to create models that explained its formation and behavior. But when confronted with hundreds of exosolar systems—many with features very different from our own—the holes in some of these models become very obvious.

The difference was made apparent by a publication that I only recently became aware of. The problem is a relatively subtle one: many of the "hot Jupiters" that orbit close to their host stars are physically larger than their mass indicates they should be. There are a number of competing models that seek to explain this apparent discrepancy, but Derek Buzasi, a researcher at Florida Gulf Coast University, has added another one. His work suggests that the solar magnetic field could have possibly created an electrical current that flows through the planet—with hundreds of megavolts of potential.

The issue causing the confusion is pretty simple. Gas giants, as their name implies, are mostly gas. Their density is set by the competing forces of gravity and pressure, with the pressure being a product of the temperature of the planet. The temperature in turn is set by a combination of the energy input from the local star and the heat left over from the gas' gravitational collapse into the planet. Given the age of the exosolar system, we can calculate both of these values and therefore provide an estimate of what the planet's density should be.

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Astronomers image smallest exoplanet yet

With the central star removed, it's possible to directly image the planet.
ESO

We're aware of a huge number of exoplanets now, but we've only seen about a dozen. Most of the rest have been detected through their effects on the light emitted by the stars they orbit. Some of the bodies we've imaged directly may not even be planets; they're so large that they may have briefly undergone fusion, which puts them in the brown dwarf category.

But astronomers have now imaged an object that very clearly falls into the planetary category, as it may be as little as four times the mass of Jupiter (if one could ever use "little" for a planet that size). Like all good scientific findings, it comes with a bit of mystery: we don't think a planet that size can form where this one orbits.

The exoplanet was discovered as part of a survey of young stars that are relatively close to the Sun. "Close to the Sun" simply means that we can obtain more light from them; "young stars" mean that any planets orbiting them will also be young. In the case of gas giants, that means they'll be hot, as they will still be radiating away the heat of their formation. One of the stars the survey imaged was HD 95086, which is about 300 light years from Earth. In addition to being young—previous estimates have placed the star at either 10 or 17 million years old—the star was already known to have a dusty environment, which could indicate a planet-forming disk.

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RIP and good planet hunting, Kepler

Very few experiments have changed the way we perceive our Universe, but the Kepler exoplanet survey telescope is one such example. Simply by monitoring a single patch of the sky continuously, it provided a new understanding of how many planets exist in the galaxy. Since its launch in 2009, Kepler identified 115 exoplanets with over 2,700 other potential planet candidates—including a number that are comparable in size to Earth or orbiting within the habitable zone where liquid water might exist.

However, Kepler is an orbiting telescope, unreachable by spacecraft for repairs. Today, NASA announced that a reaction wheel—required to keep the telescope pointed steadily in one direction—ceased functioning. This is the second reaction wheel failure, meaning Kepler can't continue to monitor the same stars and their exoplanets it has watched since 2009.

The Kepler engineering team had been anticipating this problem for some months, so this news was not unexpected. NASA associate administrator John Grunsfeld mentioned hope that engineers could restore communication with the control system managing the reaction wheel, but the fact that this state of failure has persisted for some days indicates how faint the hope is.

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RIP and good planet hunting, Kepler

Very few experiments have changed the way we perceive our Universe, but the Kepler exoplanet survey telescope is one such example. Simply by monitoring a single patch of the sky continuously, it provided a new understanding of how many planets exist in the galaxy. Since its launch in 2009, Kepler identified 115 exoplanets with over 2,700 other potential planet candidates—including a number that are comparable in size to Earth or orbiting within the habitable zone where liquid water might exist.

However, Kepler is an orbiting telescope, unreachable by spacecraft for repairs. Today, NASA announced that a reaction wheel—required to keep the telescope pointed steadily in one direction—ceased functioning. This is the second reaction wheel failure, meaning Kepler can't continue to monitor the same stars and their exoplanets it has watched since 2009.

The Kepler engineering team had been anticipating this problem for some months, so this news was not unexpected. NASA associate administrator John Grunsfeld mentioned hope that engineers could restore communication with the control system managing the reaction wheel, but the fact that this state of failure has persisted for some days indicates how faint the hope is.

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RIP and good planet hunting, Kepler

Very few experiments have changed the way we perceive our Universe, but the Kepler exoplanet survey telescope is one such example. Simply by monitoring a single patch of the sky continuously, it provided a new understanding of how many planets exist in the galaxy. Since its launch in 2009, Kepler identified 115 exoplanets with over 2,700 other potential planet candidates—including a number that are comparable in size to Earth or orbiting within the habitable zone where liquid water might exist.

However, Kepler is an orbiting telescope, unreachable by spacecraft for repairs. Today, NASA announced that a reaction wheel—required to keep the telescope pointed steadily in one direction—ceased functioning. This is the second reaction wheel failure, meaning Kepler can't continue to monitor the same stars and their exoplanets it has watched since 2009.

The Kepler engineering team had been anticipating this problem for some months, so this news was not unexpected. NASA associate administrator John Grunsfeld mentioned hope that engineers could restore communication with the control system managing the reaction wheel, but the fact that this state of failure has persisted for some days indicates how faint the hope is.

Read 2 remaining paragraphs | Comments

RIP and good planet hunting, Kepler

Very few experiments have changed the way we perceive our Universe, but the Kepler exoplanet survey telescope is one such example. Simply by monitoring a single patch of the sky continuously, it provided a new understanding of how many planets exist in the galaxy. Since its launch in 2009, Kepler identified 115 exoplanets with over 2,700 other potential planet candidates—including a number that are comparable in size to Earth or orbiting within the habitable zone where liquid water might exist.

However, Kepler is an orbiting telescope, unreachable by spacecraft for repairs. Today, NASA announced that a reaction wheel—required to keep the telescope pointed steadily in one direction—ceased functioning. This is the second reaction wheel failure, meaning Kepler can't continue to monitor the same stars and their exoplanets it has watched since 2009.

The Kepler engineering team had been anticipating this problem for some months, so this news was not unexpected. NASA associate administrator John Grunsfeld mentioned hope that engineers could restore communication with the control system managing the reaction wheel, but the fact that this state of failure has persisted for some days indicates how faint the hope is.

Read 2 remaining paragraphs | Comments

RIP and good planet hunting, Kepler

Very few experiments have changed the way we perceive our Universe, but the Kepler exoplanet survey telescope is one such example. Simply by monitoring a single patch of the sky continuously, it provided a new understanding of how many planets exist in the galaxy. Since its launch in 2009, Kepler identified 115 exoplanets with over 2,700 other potential planet candidates—including a number that are comparable in size to Earth or orbiting within the habitable zone where liquid water might exist.

However, Kepler is an orbiting telescope, unreachable by spacecraft for repairs. Today, NASA announced that a reaction wheel—required to keep the telescope pointed steadily in one direction—ceased functioning. This is the second reaction wheel failure, meaning Kepler can't continue to monitor the same stars and their exoplanets it has watched since 2009.

The Kepler engineering team had been anticipating this problem for some months, so this news was not unexpected. NASA associate administrator John Grunsfeld mentioned hope that engineers could restore communication with the control system managing the reaction wheel, but the fact that this state of failure has persisted for some days indicates how faint the hope is.

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Kepler spots two super Earths, one squarely in the habitable zone

Liquid water is one of the essential ingredients of life on Earth and it has properties conducive to life in general, so researchers have defined the concept of a habitable zone with water as its focus. For astronomers, the habitable zone is the area far enough from a host star that a planet would be cool enough to support liquid water, but not so far that the water would be frozen. Although there are many caveats to this definition—everything from the presence of greenhouse gasses to clouds will shift a planet's average surface temperature—the concept helps drive the search for a planet capable of supporting life.

The caveats, however, have led to a number of arguments over whether a given exoplanet is likely able to host liquid water, with some candidates shifting in and out of the habitable zone more than once. Still, it's pretty clear that, given the large number of reported candidate exoplanets, the odds suggest we've already spotted one. Today, scientists are announcing an exosolar system that has two planets that are both likely to be within the habitable zone, along with three others that are closer to the host star.

The findings come from the Kepler mission, which is dealing with a backlog of roughly 2,000 planet candidates to sort through and confirm. Normally, confirmation requires observing changes in the light emitted by the host star, which gets dragged closer to and further from the Earth as the planets circle it. However, this method requires that the planets either be large or orbiting close to the star so that their gravitational influence is big enough to shift it.

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Want to name an exoplanet after your cat? IAU says dream on

It has been incredibly exciting to bring you the latest news on the hunt for planets outside our Solar System. Over the past few years, the planets we've spotted have gotten closer to Earth's size, closer to the Solar System, and far, far more numerous. There's almost nothing that could dull the excitement—except, perhaps, the planets' names. Monikers like KOI-135 b and HAT-P-5 b don't exactly inspire a sense of the mysterious unknown.

Even the International Astronomical Union (IAU) admits they're a bit dull. "While exoplanet names such as 16 Cygni Bb or HD 41004 Ab may seem boring when considering the names of planets in our own Solar System, the vast number of objects in our Universe—galaxies, stars, and planets to name just a few—means that a clear and systematic system for naming these objects is vital," the organization has noted. But at least one company has decided that clear and systematic is not its thing, and it has started selling the chance to name a planet.

Or rather nominate a name and download a certificate of said nomination. People can then vote on the nominees, with voting closing on Monday night. The company running the process says it donates some of its funds to astronomy research and education efforts.

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NASA funds telescope designed to spot Earth-like planets

NASA has selected a planet-tracking satellite for funding, according to a press release that the administration released on Friday. The Transiting Exoplanet Survey Satellite (TESS), proposed by researchers at MIT, will use four telescopes to conduct a survey of the sky, looking specifically for terrestrial planets in the habitable zones surrounding the nearest and brightest stars. Its method of spotting the planets will be similar to that of the Kepler telescope currently in orbit.

MIT’s TESS proposal, along with 11 others, was originally selected for evaluation in October 2011. The project is now set to receive up to $200 million in funding to complete the mission under NASA’s Astrophysics Explorer Program.

While the Kepler telescope is able to resolve distant planets in one specific area of space, Kepler is limited to looking at only 0.28 percent of the entire sky. TESS will be able to survey the entire sky but will be limited to resolving details of nearby stars. It will be able to spot planets ranging in size from Earth equivalents to gas giants.

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