OrbitalHub

Wikipedia dicit:

The Imaging X-ray Polarimetry Explorer, commonly known as IXPE, is a space observatory with three identical telescopes designed to measure the polarization of cosmic X-rays. The mission will study exotic astronomical objects and permit mapping the magnetic fields of black holes, neutron stars, pulsars, supernova remnants, magnetars, quasars, and active galactic nuclei. The high-energy X-ray radiation from these objects’ surrounding environment can be polarized – vibrating in a particular direction. Studying the polarization of X-rays reveals the physics of these objects and can provide insights into the high-temperature environments where they are created.

The IXPE mission was announced on 3 January 2017. It is being developed by NASA’s Small Explorer program (SMEX) and is slated for launch on 9 December 2021. The estimated cost of the mission and its two-year operation is US$188 million (the launch cost is US$50.3 million). The goal of the IXPE mission is to expand understanding of high-energy astrophysical processes and sources, in support of NASA’s first science objective in astrophysics: “Discover how the universe works”. By obtaining X-ray polarimetry and polarimetric imaging of cosmic sources, IXPE addresses two specific science objectives: to determine the radiation processes and detailed properties of specific cosmic X-ray sources or categories of sources; and to explore general relativistic and quantum effects in extreme environments.

During IXPE’s two-year mission, it will study targets such as active galactic nuclei, quasars, pulsars, pulsar wind nebulae, magnetars, accreting X-ray binaries, supernova remnants, and the Galactic Center.

Video credit: NASA

NASA dicit:

About 5,000 light-years from Earth, the stunning nebula NGC 2392 formed after the demise of a star like our Sun.

In this sonification, the image is scanned clockwise like a radar. The radius is mapped to pitch, so light farther from the center is higher pitched. The outline of the nebula’s shell can be heard in the rising and falling of pitch, punctuated by its spokes. Brightness controls the volume.

The nebula was discovered by William Herschel on January 17, 1787, in Slough, England. He described it as “A star 9th magnitude with a pretty bright middle, nebulosity equally dispersed all around. A very remarkable phenomenon. NGC 2392 WH IV-45 is included in the Astronomical League’s Herschel 400 observing program.

Video credit: NASA Goddard

NASA dicit:

Scientists have reached a new frontier in our understanding of pulsars, the dense, whirling remains of exploded stars, thanks to observations from NASA’s Neutron star Interior Composition Explorer (NICER). Data from this X-ray telescope aboard the International Space Station has produced the first precise and dependable measurements of both a pulsar’s size and its mass.

The pulsar in question, J0030+0451 (J0030 for short), is a solitary pulsar that lies 1,100 light-years away in the constellation Pisces. While measuring the pulsar’s heft and proportions, NICER revealed that the shapes and locations of million-degree hot spots on the pulsar’s surface are much stranger than generally thought.

Using NICER observations, two groups of scientists mapped J0030’s hot spots using independent methods and converged on nearly identical results for its mass and size. One team, led by researchers at the University of Amsterdam, determined the pulsar is around 1.3 times the Sun’s mass, 15.8 miles (25.4 kilometers) across and has two hot spots — one small and circular, the other long and crescent-shaped. A second team found J0030 is about 1.4 times the Sun’s mass, about 16.2 miles (26 kilometers) wide and has two or three oval-shaped hot spots. All spots in all models are in the pulsar’s southern hemisphere — unlike textbook images where the spots lie on opposite sides other at each magnetic poles.

Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (USRA): Producer/Jeanette Kazmierczak (University of Maryland College Park): Science Writer/Francis Reddy (University of Maryland College Park): Science Writer/Michael Lentz (USRA): Animator/Barb Mattson (University of Maryland College Park): Narrator/Zaven Arzoumanian (NASA/GSFC): Scientist

NASA dicit:

Unprecedented observations of a nova outburst in 2018 by a trio of satellites, including NASA’s Fermi and NuSTAR space telescopes, have captured the first direct evidence that most of the explosion’s visible light arose from shock waves — abrupt changes of pressure and temperature formed in the explosion debris.

A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. It occurs when a stream of hydrogen from a companion star flows onto the surface of a white dwarf, a compact stellar cinder not much larger than Earth.

The 2018 outburst originated from a star system later dubbed V906 Carinae, which lies about 13,000 light-years away in the constellation Carina. Over time — perhaps tens of thousands of years for a so-called classical nova like V906 Carinae — the white dwarf’s deepening hydrogen layer reaches critical temperatures and pressures. It then erupts in a runaway reaction that blows off all of the accumulated material.

Fermi detected its first nova in 2010 and has observed 14 to date. Gamma rays the highest-energy form of light require processes that accelerate subatomic particles to extreme energies, which happens in shock waves. When these particles interact with each other and with other matter, they produce gamma rays. Because the gamma rays appear at about the same time as a nova’s peak in visible light, astronomers concluded that shock waves play a more fundamental role in the explosion and its aftermath.

The Fermi and BRITE data show flares in both wavelengths at about the same time, so they must share the same source shock waves in the fast-moving debris.

Observations of one flare using NASA’s NuSTAR space telescope showed a much lower level of X-rays compared to the higher-energy Fermi data, likely because the nova ejecta absorbed most of the X-rays. High-energy light from the shock waves was repeatedly absorbed and reradiated at lower energies within the nova debris, ultimately only escaping at visible wavelengths.

Video credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA): Lead Animator/Chris Smith (USRA): Producer/Scott Wiessinger (USRA): Producer/Francis Reddy (University of Maryland College Park): Lead Science Writer/Scott Wiessinger (USRA): Narrator/Scott Wiessinger (USRA): Editor

NASA dicit:

Taking advantage of the total lunar eclipse of January 2019, astronomers, using NASA’s Hubble Space Telescope, have measured the amount of ozone in Earth’s atmosphere. The method used serves as a proxy for how they will observe Earth-like planets around other stars in search for worlds similar to our own.

Video credit: NASA’s Goddard Space Flight Center/Paul Morris (USRA): Lead Producer/Krystofer Kim (USRA): Lead Animator/Cassandra Morris: Voice over Talent

NASA dicit:

Scientists using NASA’s Hubble Space Telescope have found evidence that a planet orbiting a distant star that may have lost its atmosphere but gained a second one through volcanic activity.

The planet, GJ 1132 b, is hypothesized to have begun as a gaseous world with a thick hydrogen blanket of atmosphere. Starting out at several times the diameter of Earth, this so-called “sub-Neptune” is believed to have quickly lost its primordial hydrogen and helium atmosphere due to the intense radiation of the hot, young star it orbits. In a short period of time, such a planet would be stripped down to a bare core about the size of Earth.

Video credit: NASA’s Goddard Space Flight Center/Paul Morris