OrbitalHub

ESA dixit:

“ESA’s XMM-Newton has spotted surprising changes in the powerful streams of gas from two massive stars, suggesting that colliding stellar winds don’t behave as expected. Massive stars – several times larger than our Sun – lead turbulent lives, burning their nuclear fuel rapidly and pouring large amounts of material into their surroundings throughout their short but sparkling lives.

These fierce stellar winds can carry the equivalent of Earth’s mass in a month and travel at millions of kilometres per hour, so when two such winds collide they unleash enormous amounts of energy. The cosmic clash heats the gas to millions of degrees, making it shine brightly in X-rays.

Normally, colliding winds change little because neither do the stars nor their orbits. However, some massive stars behave dramatically. This is the case with HD 5980, a pairing of two huge stars each 60 times the mass of our Sun and only about 100 million kilometres apart – closer than we are to our star. One had a major outburst in 1994, reminiscent of the eruption that turned Eta Carinae into the second brightest star in the sky for about 18 years in the 19th century. While it is now too late to study Eta Carinae’s historic eruption, astronomers have been observing HD 5980 with X-ray telescopes to study the hot gas.”

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Video credit: ESA

NASA dixit:

“Astronomers using NASA’s Hubble Space Telescope have conducted the first spectroscopic survey of the Earth-sized planets (d, e, f, and g) within the habitable zone around the nearby star TRAPPIST-1. This study is a follow-up to Hubble observations made in May 2016 of the atmospheres of the inner TRAPPIST-1 planets b and c. Hubble reveals that at least three of the exoplanets (d, e, and f) do not seem to contain puffy, hydrogen-rich atmospheres similar to gaseous planets such as Neptune.

Additional observations are needed to determine the hydrogen content of the fourth planet’s (g) atmosphere. Hydrogen is a greenhouse gas, which smothers a planet orbiting close to its star, making it hot and inhospitable to life. The results, instead, favor more compact atmospheres like those of Earth, Venus, and Mars.

By not detecting the presence of a large abundance of hydrogen in the planets’ atmospheres, Hubble is helping to pave the way for NASA’s James Webb Space Telescope, scheduled to launch in 2019. Webb will probe deeper into the planetary atmospheres, searching for heavier gases such as carbon dioxide, methane, water, and oxygen. The presence of such elements could offer hints of whether life could be present, or if the planet were habitable.

“Hubble is doing the preliminary reconnaissance work so that astronomers using Webb know where to start,” said Nikole Lewis of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, co-leader of the Hubble study. “Eliminating one possible scenario for the makeup of these atmospheres allows the Webb telescope astronomers to plan their observation programs to look for other possible scenarios for the composition of these atmospheres.”

The planets orbit a red dwarf star that is much smaller and cooler than our Sun. The four alien worlds are members of a seven-planet system around TRAPPIST-1. All seven of the planetary orbits are closer to their host star than Mercury is to our Sun. Despite the planets’ close proximity to TRAPPIST-1, the star is so much cooler than our Sun that liquid water could exist on the planets’ surfaces.”

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Video credit: NASA’s Goddard Space Flight Center

NASA dixit:

“The Transiting Exoplanet Survey Satellite (TESS) is the next step in the search for planets outside of our solar system, including those that could support life. The mission will find exoplanets that periodically block part of the light from their host stars, events called transits. TESS will survey 200,000 of the brightest stars near the sun to search for transiting exoplanets. The mission is scheduled to launch in 2018.”

Music credit: “Prototype” and “Trial” both from Killer Tracks

Video credit: NASA’s Goddard Space Flight Center

NASA dixit:

“Light from a supernova explosion in the nearby starburst galaxy M82 is reverberating off a huge dust cloud in interstellar space. The supernova, called SN 2014J, occurred at the upper right of M82, and is marked by an “X.” The supernova was discovered on January 21, 2014.

The inset images at top reveal an expanding shell of light from the stellar explosion sweeping through interstellar space, called a “light echo.” The images were taken 10 months to nearly two years after the violent event (November 6, 2014 to October 12, 2016). The light is bouncing off a giant dust cloud that extends 300 to 1,600 light-years from the supernova and is being reflected toward Earth.

SN 2014J is classified as a Type Ia supernova and is the closest such blast in at least four decades. A Type Ia supernova occurs in a binary star system consisting of a burned-out white dwarf and a companion star. The white dwarf explodes after the companion dumps too much material onto it. The image of M82 reveals a bright blue disk, webs of shredded clouds, and fiery-looking plumes of glowing hydrogen blasting out of its central regions.

Close encounters with its larger neighbor, the spiral galaxy M81, is compressing gas in M82 and stoking the birth of multiple star clusters. Some of these stars live for only a short time and die in cataclysmic supernova blasts, as shown by SN 2014J.

Located 11.4 million light-years away, M82 appears high in the northern spring sky in the direction of the constellation Ursa Major, the Great Bear. It is also called the “Cigar Galaxy” because of the elliptical shape produced by the oblique tilt of its starry disk relative to our line of sight.”

Music credit: “Little Effort” by Christopher Franke [BMI]; Killer Tracks [BMI]; Killer Tracks Production Music

Video credit: NASA’s Goddard Space Flight Center/Katrina Jackson

NASA dixit:

“By combining the visible and infrared capabilities of the Hubble and Spitzer space telescopes, astronomers and visualization specialists from NASA’s Universe of Learning program have created a spectacular, three-dimensional, fly-through movie of the magnificent Orion nebula, a nearby stellar nursery. Using actual scientific data along with Hollywood techniques, a team at the Space Telescope Science Institute in Baltimore, Maryland, and the Caltech/IPAC in Pasadena, California, has produced the best and most detailed multi-wavelength visualization yet of the Orion nebula.”

Video credit: NASA/Space Telescope Science Institute

NASA dixit:

“Observations by NASA’s Swift spacecraft, now renamed the Neil Gehrels Swift Observatory after the mission’s late principal investigator, have captured an unprecedented change in the rotation of a comet. Images taken in May 2017 reveal that comet 41P/Tuttle-Giacobini-Kresak — 41P for short — was spinning three times slower than it was in March, when it was observed by the Discovery Channel Telescope at Lowell Observatory in Arizona. The abrupt slowdown is the most dramatic change in a comet’s rotation ever seen.

Comet 41P orbits the Sun every 5.4 years. As a comet nears the Sun, increased heating causes its surface ice to change directly to a gas, producing jets that launch dust particles and icy grains into space. This material forms an extended atmosphere, called a coma.

Ground-based observations established the 41P’s initial rotational period at about 20 hours in early March 2017 and detected its slowdown later the same month. The comet passed 13.2 million miles (21.2 million km) from Earth on April 1, and eight days later made its closest approach to the Sun. Swift’s Ultraviolet/Optical Telescope imaged the comet from May 7 to 9, revealing brightness variations associated with material recently ejected into the coma. These slow changes indicated 41P’s rotation period had more than doubled, to between 46 and 60 hours.

UVOT-based estimates of 41P’s water production, coupled with the body’s small size, suggest that more than half of its surface area contains sunlight-activated jets. That’s a far greater fraction of active real estate than on most comets, which typically support jets over only about 3 percent of their surfaces. Astronomers suspect these active areas are favorably oriented to produce torques that slowed 41P’s spin.

Such a slow spin could make the comet’s rotation unstable, allowing it to begin tumbling with no fixed rotational axis. This would produce a dramatic change in the comet’s seasonal heating and may result in future outbursts of activity.”

Music credit: “Valley of Crystals” from Killer Tracks

Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger