In the mid-1800s, mariners sailing the southern seas navigated at night by a brilliant star in the constellation Carina. The star, named Eta Carinae, was the second brightest star in the sky for more than a decade. Those mariners could hardly have imagined that by the mid-1860s the brilliant orb would no longer be visible. Eta Carinae was enveloped by a cloud of dust ejected during a violent outburst named “The Great Eruption.”
Because of Eta Carinae’s violent history, astronomers have kept watch over its activities. Although Hubble has monitored the volatile superstar for 25 years, it still is uncovering new revelations. Using Hubble to map the ultraviolet-light glow of magnesium embedded in warm gas, astronomers were surprised to discover the gas in places they had not seen it before.
Astronomers using NASA’s Fermi Gamma-ray Space Space Telescope and the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have found a pulsar hurtling through space at nearly 2.5 million miles an hour — so fast it could travel the distance between Earth and the Moon in just 6 minutes.
Pulsars are superdense, rapidly spinning neutron stars left behind when a massive star explodes. This one, dubbed PSR J0002+6216 (J0002 for short), sports a radio-emitting tail pointing directly toward the expanding debris from a recent supernova explosion. Thanks to its narrow dart-like tail and a fortuitous viewing angle, astronomers can trace this pulsar straight back to its birthplace. Further study of J0002 will help us better understand how these explosions are able to ‘kick’ neutron stars to such high speed.
The pulsar is located about 6,500 light-years away in the constellation Cassiopeia. It was discovered in 2017 by a citizen-science project called Einstein@Home , which uses downtime on the computers of volunteers to process Fermi gamma-ray data and has identified 23 gamma-ray pulsars to date. J0002 spins 8.7 times a second, producing a pulse of gamma rays with each rotation, and has about 1.5 times the mass of the Sun. The pulsar lies about 53 light-years from the center of a supernova remnant called CTB 1. Its rapid motion through interstellar gas results in shock waves that produce the tail of magnetic energy and accelerated particles detected at radio wavelengths using the VLA. The tail extends 13 light-years and clearly points back to the center of CTB 1.
Using Fermi data and a technique called pulsar timing, the team was able to measure how quickly and in what direction the pulsar was moving across our line of sight thanks to Fermi’s 10-year data covering the entire sky. J0002 is speeding through space five times faster than the average pulsar and faster than 99 percent of those with measured speeds. It will eventually escape our galaxy.
Francis Reddy (University of Maryland College Park): Lead Science Writer
Scott Wiessinger (USRA): Lead Producer
Jeanette Kazmierczak (University of Maryland College Park): Science Writer
Music credit: “Forensic Scientist” from Killer Tracks
Astronomers have put together the largest and most comprehensive “history book” of galaxies into one single image, using 16 years’ worth of observations from NASA’s Hubble Space Telescope.
The deep-sky mosaic, created from nearly 7,500 individual exposures, provides a wide portrait of the distant universe, containing 265,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the big bang. The faintest and farthest galaxies are just one ten-billionth the brightness of what the human eye can see. The universe’s evolutionary history is also chronicled in this one sweeping view. The portrait shows how galaxies change over time, building themselves up to become the giant galaxies seen in the nearby universe.
This ambitious endeavor, called the Hubble Legacy Field, also combines observations taken by several Hubble deep-field surveys, including the eXtreme Deep Field (XDF), the deepest view of the universe. The wavelength range stretches from ultraviolet to near-infrared light, capturing the key features of galaxy assembly over time.
Video Credit: NASA, ESA, G. Illingworth (University of California, Santa Cruz) and G. Bacon (STScI)
On the evening of March 6, 2019, the Moon started to transit the Sun, then doubled back and retraced its steps in the other direction — at least, that’s what it looked like from the perspective of NASA’s Solar Dynamics Observatory, or SDO, in orbit around Earth. The relative speeds and positions of the Moon, the Sun and NASA’s Solar Dynamics Observatory resulted in this unusual lunar transit where the Moon appears to pause and reverse course.
“Space weather describes the changing environment throughout the Solar System, driven by the energetic and unpredictable nature of our Sun. Solar wind, solar flares and Coronal Mass Ejections can result in geomagetic storms on Earth, potentially damaging satellites in space and the technologies that rely on them, as well as infrastructure on the ground.
ESA’s future Lagrange mission will keep constant watch on the Sun. The satellite, located at the fifth Lagrange point, will send early warning of potentially harmful solar activity before it affects satellites in orbit or power grids on the ground, giving operators the time to act to protect vital infrastructure.”
“The Transiting Exoplanet Survey Satellite (TESS) is a space telescope for NASA’s Explorers program, designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the Kepler mission. It was launched on April 18, 2018 atop a Falcon 9 rocket. During its primary mission, it is expected to find more than 20,000 exoplanets compared to about 3,800 exoplanets known when it launched.
The primary mission objective for TESS is to survey the brightest stars near the Earth for transiting exoplanets over a two-year period. The TESS satellite uses an array of wide-field cameras to perform a survey of 85% of the sky. With TESS, it is possible to study the mass, size, density and orbit of a large cohort of small planets, including a sample of rocky planets in the habitable zones of their host stars. TESS will provide prime targets for further characterization by the James Webb Space Telescope, as well as other large ground-based and space-based telescopes of the future. While previous sky surveys with ground-based telescopes have mainly detected giant exoplanets, TESS will find a large number of small planets around the nearest stars in the sky. TESS records the nearest and brightest main sequence stars hosting transiting exoplanets, which are the most favorable targets for detailed investigations.
TESS uses a novel highly-elliptical orbit with an apogee approximately at the distance of the Moon and a perigee of 108,000 km, above the geosynchronous satellites. TESS orbits Earth twice during the time the Moon orbits once, a 2:1 resonance with the Moon. The orbit is expected to remain stable for a minimum of 10 years.”
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