Wednesday, December 11, 2019

Parker Probe Traces Solar Wind to Its Source on Sun’s Surface

NASA’s Parker Solar Probe mission has traveled closer to the Sun than any human-made object. (Image courtesy of NASA/Johns Hopkins APL)

A year ago, NASA's Parker Solar Probe flew closer to the sun than any satellite in history, collecting a spectacular trove of data from the very edge of the sun's million-degree corona. Now, that data has allowed solar physicists to map the source of a major component of the solar wind that continually peppers Earth's atmosphere, while revealing strange magnetic field reversals that could be accelerating these particles toward our planet.

Hidden Giant Planet Revealed Around Tiny White Dwarf Star

The giant planet is orbiting the white dwarf just outside the gas disc. The blast of high-energy photons that it receives from the white dwarfs evaporates its atmosphere, which is mainly composed of hydrogen, oxygen and sulphur. Whereas much of the hydrogen is forced away from the white dwarf by its ultraviolet photons in a comet-like tail, oxygen and sulphur fall towards the white dwarf, forming the disc we have detected. The light we see from the disc comes only from a few strong emission lines: oxygen lines, which we would see as red light, light up the inner part of the disc, and sulphur lines, which would appear blue, are stronger in the outer regions of the disc. Credit: University of Warwick/Mark Garlick

The first evidence of a giant planet orbiting a dead white dwarf star has been found in the form of a disc of gas formed from its evaporating atmosphere. The Neptune-like planet orbits a star a quarter of its size about once every ten days, leaving a comet-like tail of gas comprised of hydrogen, oxygen and sulphur in its wake.

Star-quake Vibrations Lead to New Estimate for Milky Way Age

An artist impression of the Milky Way, showing the thick and thin discs. Credit: NASA/JPL Caltech/R.Hurt/SSC

Star-quakes recorded by NASA’s Kepler space telescope have helped answer a long-standing question about the age of the “thick disc” of the Milky Way. In a paper published in the journal Monthly Notices of the Royal Astronomical Society, a team of 38 scientists led by researchers from Australia’s ARC Centre of Excellence for All Sky Astrophysics in Three Dimensions (ASTRO-3D) use data from the now-defunct probe to calculate that the disc is about 10 billion years old.

Sunday, December 8, 2019

Detecting Solar Flares, More in Real Time

The SUVI thematic map (right) produced by the new algorithm tracks changes in the Sun (left) over time. In the thematic map, different colors correspond to different themes: yellow corresponds to active regions, while dark blue shows quiet solar regions. Credit: J. Marcus Hughes/CU Boulder, CIRES & NCEI

Computers can learn to find solar flares and other events in vast streams of solar images and help NOAA forecasters issue timely alerts, according to a new study. The machine-learning technique, developed by scientists at CIRES and NOAA's National Centers for Environmental Information (NCEI), searches massive amounts of satellite data to pick out features significant for space weather. Changing conditions on the Sun and in space can affect various technologies on Earth, blocking radio communications, damaging power grids, and diminishing navigation system accuracy.

Gas Giant Composition Not Determined By Host Star

An artist’s conception of a young star surrounded by a primordial rotating disk of gas and dust from which planets can form. Illustration is by Robin Dienel, courtesy of the Carnegie Institution for Science.

A surprising analysis of the composition of gas giant exoplanets and their host stars shows that there isn't a strong correlation between their compositions when it comes to elements heavier than hydrogen and helium, according to new work led by Carnegie's Johanna Teske and published in the Astronomical Journal. This finding has important implications for our understanding of the planetary formation process.

Saturday, December 7, 2019

A Study of Saturn’s Largest Moon May Offer Insights for Earth

Researchers used data collected from the Cassini mission between 2004 and 2017 to learn more about climate on Titan, Saturn's largest moon. Photo illustration: NASA/Cassini/Kevin Gill

Scientists studying the weather and climate of Titan, Saturn’s largest moon, have reported a significant seasonal variation in its energy budget – that is the amount of solar energy absorbed by the celestial body and the thermal energy it emits. The findings, reported in the journal Geophysical Research Letters, could lead to new insights about climate on Earth.

International Team Aims to Crack 60-year-old Mystery of Sun’s Magnetic Waves

Queen’s University Belfast scientist has led an international team to the ground-breaking discovery of why the Sun’s magnetic waves strengthen and grow as they emerge from its surface. The findings could help to solve the mystery of how the corona of the Sun maintains its multi-million degree temperatures.

Instrument Confirms Solar Wind Slows Farther Away from the Sun

The SWAP instrument aboard NASA’s New Horizons spacecraft has confirmed that the solar wind slows as it travels farther from the Sun. This schematic of the heliosphere shows the solar wind begins slowing at approximately 4 AU radial distance from the Sun and continues to slow as it moves toward the outer solar system and picks up interstellar material. Current extrapolations reveal the termination shock may currently be closer than found by the Voyager spacecraft. However, increasing solar activity will soon expand the heliosphere and push the termination shock farther out, possibly to the 84-94 AU range encountered by the Voyager spacecraft.

Measurements taken by the Solar Wind Around Pluto (SWAP) instrument aboard NASA’s New Horizons spacecraft are providing important new insights from some of the farthest reaches of space ever explored. In a paper recently published in The Astrophysical Journal, a team led by Southwest Research Institute shows how the solar wind — the supersonic stream of charged particles blown out by the Sun — evolves at increasing distances from the Sun.