OrbitalHub

Wikipedia dicit:

A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white holes and quark stars), neutron stars are the smallest and densest currently known class of stellar objects. Neutron stars have a radius on the order of 10 kilometres (6 mi) and a mass of about 1.4 solar masses. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei.

Once formed, they no longer actively generate heat and cool over time; however, they may still evolve further through collision or accretion. Most of the basic models for these objects imply that neutron stars are composed almost entirely of neutrons (subatomic particles with no net electrical charge and with slightly larger mass than protons); the electrons and protons present in normal matter combine to produce neutrons at the conditions in a neutron star. Neutron stars are partially supported against further collapse by neutron degeneracy pressure, a phenomenon described by the Pauli exclusion principle, just as white dwarfs are supported against collapse by electron degeneracy pressure. However, neutron degeneracy pressure is not by itself sufficient to hold up an object beyond 0.7 M☉ and repulsive nuclear forces play a larger role in supporting more massive neutron stars. If the remnant star has a mass exceeding the Tolman–Oppenheimer–Volkoff limit of around 2 solar masses, the combination of degeneracy pressure and nuclear forces is insufficient to support the neutron star. It continues collapsing to form a black hole. The most massive neutron star detected so far, PSR J0952–0607, is estimated to be 2.35±0.17 solar masses.

Neutron stars that can be observed are very hot and typically have a surface temperature of around 600000 K. Neutron star material is remarkably dense: a normal-sized matchbox containing neutron-star material would have a weight of approximately 3 billion tonnes, the same weight as a 0.5 cubic kilometre chunk of the Earth (a cube with edges of about 800 metres) from Earth’s surface. Their magnetic fields are between 108 and 1015 (100 million and 1 quadrillion) times stronger than Earth’s magnetic field. The gravitational field at the neutron star’s surface is about 2×1011 (200 billion) times that of Earth’s gravitational field.

Credit: NASA Goddard

Wikipedia dicit:

Transiting Exoplanet Survey Satellite (TESS, Explorer 95 or MIDEX-7) is a space telescope for NASA’s Explorer 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 18 April 2018, atop a Falcon 9 launch vehicle and was placed into a highly elliptical 13.70-day orbit around the Earth. The first light image from TESS was taken on 7 August 2018, and released publicly on 17 September 2018.

Over the course of the two-year primary mission, TESS was expected to ultimately detect about 1,250 transiting exoplanets orbiting the targeted stars, and an additional 13,000 transiting planets orbiting additional stars in the fields that TESS would observe. As of 5 November 2022, TESS had identified 5,969 candidate exoplanets, of which only 268 had been confirmed and 1720 had been dismissed as false positives. After the end of the primary mission around 4 July 2020, data from the primary mission continue to be searched for planets, while the extended missions continues to acquire additional data.

The primary mission objective for TESS was 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 provides prime targets for further characterisation by the James Webb Space Telescope (JWST), 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 and the Kepler space telescope has mostly found planets around distant stars that are too faint for characterisation, TESS finds many 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 favourable targets for detailed investigations. By providing such detailed information about planetary systems with hot Jupiters, TESS makes it possible to better understand the architecture of such systems.

Credit: NASA Goddard

NASA Goddard dicit:

This video chronicles solar activity from Aug. 12 to Dec. 22, 2022, as captured by NASA’s Solar Dynamics Observatory (SDO). From its orbit in space around Earth, SDO has steadily imaged the Sun in 4K x 4K resolution for nearly 13 years. This information has enabled countless new discoveries about the workings of our closest star and how it influences the solar system.

With a triad of instruments, SDO captures an image of the Sun every 0.75 seconds. The Atmospheric Imaging Assembly (AIA) instrument alone captures images every 12 seconds at 10 different wavelengths of light. This 133-day time lapse showcases photos taken at a wavelength of 17.1 nanometers, which is an extreme-ultraviolet wavelength that shows the Sun’s outermost atmospheric layer: the corona. Compiling images taken 108 seconds apart, the movie condenses 133 days, or about four months, of solar observations into 59 minutes. The video shows bright active regions passing across the face of the Sun as it rotates. The Sun rotates approximately once every 27 days. The loops extending above the bright regions are magnetic fields that have trapped hot, glowing plasma. These bright regions are also the source of solar flares, which appear as bright flashes as magnetic fields snap together in a process called magnetic reconnection.

While SDO has kept an unblinking eye pointed toward the Sun, there have been a few moments it missed. Some of the dark frames in the video are caused by Earth or the Moon eclipsing SDO as they pass between the spacecraft and the Sun. Other blackouts are caused by instrumentation being down or data errors. SDO transmits 1.4 terabytes of data to the ground every day. The images where the Sun is off-center were observed when SDO was calibrating its instruments.

SDO and other NASA missions will continue to watch our Sun in the years to come, providing further insights about our place in space and information to keep our astronauts and assets safe.

Music Credit: The music is a continuous mix from Lars Leonhard’s “Geometric Shapes” album, courtesy of the artist.

Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (PAO): Lead Producer/Tom Bridgman (SVS): Lead Visualizer/Scott Wiessinger (PAO): Editor

Wikipedia dicit:

The James Webb Space Telescope (JWST) is a space telescope which conducts infrared astronomy. As the largest optical telescope in space, its high resolution and sensitivity allow it to view objects too old, distant, or faint for the Hubble Space Telescope. This will enable investigations across many fields of astronomy and cosmology, such as observation of the first stars, the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets.

The U.S. National Aeronautics and Space Administration (NASA) led JWST’s design and development and partnered with two main agencies: the European Space Agency (ESA) and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center (GSFC) in Maryland managed telescope development, the Space Telescope Science Institute in Baltimore on the Homewood Campus of Johns Hopkins University operates JWST, and the prime contractor was Northrop Grumman. The telescope is named after James E. Webb, who was the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and Apollo programs.

The James Webb Space Telescope was launched on 25 December 2021 on an Ariane 5 rocket from Kourou, French Guiana, and arrived at the Sun–Earth L2 Lagrange point in January 2022. The first JWST image was released to the public via a press conference on 11 July 2022.

JWST’s primary mirror consists of 18 hexagonal mirror segments made of gold-plated beryllium, which combined create a 6.5-meter-diameter (21 ft) mirror, compared with Hubble’s 2.4 m (7 ft 10 in). This gives JWST a light-collecting area of about 25 square meters, about six times that of Hubble. Unlike Hubble, which observes in the near ultraviolet and visible (0.1 to 0.8 μm), and near infrared (0.8–2.5 μm) spectra, JWST observes in a lower frequency range, from long-wavelength visible light (red) through mid-infrared (0.6–28.3 μm). The telescope must be kept extremely cold, below 50 K (−223 °C; −370 °F), such that the infrared light emitted by the telescope itself does not interfere with the collected light. It is deployed in a solar orbit near the Sun–Earth L2 Lagrange point, about 1.5 million kilometers (930,000 mi) from Earth, where its five-layer sunshield protects it from warming by the Sun, Earth, and Moon.

Credit: Northrop Grumman

NASA dicit:

A new NASA and Durham University simulation puts forth a different theory of the Moon’s origin – the Moon may have formed in a matter of hours, when material from the Earth and a Mars sized-body were launched directly into orbit after the impact. The simulations used in this research are some of the most detailed of their kind, operating at the highest resolution of any simulation run to study the Moon’s origins or other giant impacts.

Credit: NASA/ Durham University/Jacob Kegerreis

NASA Goddard dicit:

Welcome to one of the most active galaxies in our cosmic neighborhood, NGC 1569. This starburst galaxy creates stars at a rate 100 times faster than in our own galaxy, the Milky Way!

Scientists represented information in this Hubble image with sound to create a beautiful sonification with a bottom to top scan. Brighter light is higher pitched and louder. The three color channels used to process this image are each given their own pitch range, with red representing lower pitches, green in medium pitches, and blue in high pitches.

Sonification credits: SYSTEM Sounds (M. Russo, A. Santaguida)

Credit: NASA Goddard