KREUZADER (Posts tagged space)

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A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass mc sin...

A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU

Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass mc sin ic = 5.8 ± 1.9M⊕ and orbital period Pc=5.21+0.26−0.22 years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.

Source: advances.sciencemag.org
astronomy space exoplanet proxima centauri
Astronomers discover class of strange objects near our galaxy’s enormous black hole Astronomers from UCLA’s Galactic Center Orbits Initiative have discovered a new class of bizarre objects at the center of our galaxy, not far from the supermassive...

Astronomers discover class of strange objects near our galaxy’s enormous black hole

Astronomers from UCLA’s Galactic Center Orbits Initiative have discovered a new class of bizarre objects at the center of our galaxy, not far from the supermassive black hole called Sagittarius A*. They published their research in the Jan. 16 issue of the journal Nature.

“These objects look like gas and behave like stars,” said co-author Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics and director of the UCLA Galactic Center Group.

Source: newsroom.ucla.edu
astronomy space
Water production rates and activity of interstellar comet 2I/Borisov We observed the interstellar comet 2I/Borisov using the Neil Gehrels-Swift Observatory’s Ultraviolet/Optical Telescope. We obtained images of the OH gas and dust surrounding the...

Water production rates and activity of interstellar comet 2I/Borisov

 We observed the interstellar comet 2I/Borisov using the Neil Gehrels-Swift Observatory’s Ultraviolet/Optical Telescope. We obtained images of the OH gas and dust surrounding the nucleus at four epochs spaced before and just after perihelion (-2.56 AU to 2.03 AU). Water production rates increased steadily before perihelion from (7.0±1.5)×1026 molecules s−1 on Nov. 1, 2019 to (10.7±1.2)×1026 molecules s−1 on Dec. 1. This rate of increase in water production rate is slower than that of most Jupiter-family comets and quicker than most dynamically new comets. After perihelion, the water production rate decreased rapidly to (4.9±0.9)×1026 molecules s−1 on Dec. 21. Our sublimation model constrains the minimum radius of the nucleus to 0.37 km, and indicates an active fraction of at least 55% of the surface. A(0)fρ calculations show variation between 90 and 106 cm with a slight trend peaking before the perihelion, lower than previous and concurrent published values. The observations confirm that 2I/Borisov is carbon-chain depleted and enriched in NH2 relative to water.

Source: arxiv.org
comet comet borisov astronomy space
Not all fast radio bursts are created equal Millisecond-duration, extragalactic radio flashes called fast radio bursts1,2 (FRBs) present many puzzles that are strikingly similar to past mysteries concerning phenomena now known as quasars and γ-ray...

Not all fast radio bursts are created equal

Millisecond-duration, extragalactic radio flashes called fast radio bursts1,2 (FRBs) present many puzzles that are strikingly similar to past mysteries concerning phenomena now known as quasars and γ-ray bursts. Like FRBs, these phenomena seemed to be uniformly distributed in the sky, but of almost impossible luminosity if cosmological in origin. Ultimately, it was revealed that quasars are associated with supermassive black holes, and γ-ray bursts with the formation of black holes after supernovae (stellar explosions) or with mergers of stellar remnants called neutron stars. Repeating FRBs provide the opportunity to identify the homes and possible progenitors of FRB sources. The first known repeater was localized to a star-forming region in a tiny, metal-poor galaxy3. Writing in Nature, Marcote et al.4 pinpoint the home of a second repeater and find it to be very different.

Source: nature.com
astronomy space radio astronomy
NASA Planet Hunter Finds its 1st Earth-size Habitable-zone World NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to...

NASA Planet Hunter Finds its 1st Earth-size Habitable-zone World

NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface. Scientists confirmed the find, called TOI 700 d, using NASA’s Spitzer Space Telescope and have modeled the planet’s potential environments to help inform future observations.

TOI 700 d is one of only a few Earth-size planets discovered in a star’s habitable zone so far. Others include several planets in the TRAPPIST-1 system and other worlds discovered by NASA’s Kepler Space Telescope.

Source: nasa.gov
nasa astronomy exoplanet space
nasa

Unveiling the Center of Our Milky Way Galaxy

nasa

image

We captured an extremely crisp infrared image of the center of our Milky Way galaxy. Spanning more than 600 light-years, this panorama reveals details within the dense swirls of gas and dust in high resolution, opening the door to future research into how massive stars are forming and what’s feeding the supermassive black hole at our galaxy’s core.

image

Among the features coming into focus are the jutting curves of the Arches Cluster containing the densest concentration of stars in our galaxy, as well as the Quintuplet Cluster with a stars a million times brighter than our Sun. Our galaxy’s black hole takes shape with a glimpse of the fiery-looking ring of gas surrounding it.

The new view was made by the world’s largest airborne telescope, the Stratospheric Observatory for Infrared Astronomy, or SOFIA.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

astronomy space nasa milky way
It’s the First Orbiting Garbage Collector—or a New Kind of Space Weapon There’s a lot of junk in space. Tens of thousands of pieces of it, circling the Earth at thousands of miles per hour. Each piece is an orbital bullet that can endanger...

It’s the First Orbiting Garbage Collector—or a New Kind of Space Weapon

There’s a lot of junk in space. Tens of thousands of pieces of it, circling the Earth at thousands of miles per hour. Each piece is an orbital bullet that can endanger satellites, manned capsules, and the International Space Station.

The European Space Agency is about to pull one of the bigger hunks of garbage from orbit. But there’s a problem: The same tech that could help make space cleaner might, in the long run, also make it more dangerous.

That’s because the ESA’s ClearSpace-1 orbital garbage truck, as well as other spacecraft like it, could double as a weapon.

Source: thedailybeast.com
space satellite space war esa
Dark Matter Thermonuclear Supernova Ignition We investigate local environmental effects from dark matter (DM) on thermonuclear supernovae (SNe Ia) using publicly available archival data of 224 low-redshift events, in an attempt to shed light on the...

Dark Matter Thermonuclear Supernova Ignition

We investigate local environmental effects from dark matter (DM) on thermonuclear supernovae (SNe Ia) using publicly available archival data of 224 low-redshift events, in an attempt to shed light on the SN Ia progenitor systems. SNe Ia are explosions of carbon-oxygen (CO) white dwarfs (WDs) that have recently been shown to explode at sub-Chandrasekhar masses; the ignition mechanism remains, however, unknown. Recently, it has been shown that both weakly interacting massive particles (WIMPs) and macroscopic DM candidates such as primordial black holes (PBHs) are capable of triggering the ignition. Here, we present a method to estimate the DM density and velocity dispersion in the vicinity of SN Ia events and nearby WDs; we argue that (i) WIMP ignition is highly unlikely, and that (ii) DM in the form of PBHs distributed according to a (quasi-) log-normal mass distribution with peak log10(m0/1g)=24.9±0.9 and width σ=3.3±1.0 is consistent with SN Ia data, the nearby population of WDs and roughly consistent with other constraints from the literature.

Source: arxiv.org
astrophysics astronomy space
Future stellar flybys of the Voyager and Pioneer spacecraft The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft, launched in the 1970s, are heading out of the solar system. Using the astrometric and radial velocity data from the second Gaia data...

Future stellar flybys of the Voyager and Pioneer spacecraft

The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft, launched in the 1970s, are heading out of the solar system. Using the astrometric and radial velocity data from the second Gaia data release, we integrate the trajectories of 7.4 million stars, and the spacecraft, through a Galactic potential in order to identify those stars the spacecraft will pass closest to. The closest encounters for all spacecraft take place at separations between 0.2 and 0.5 pc within the next million years. The closest encounter will be by Pioneer 10 with the K8 dwarf HIP 117795, at 0.23 pc in 90 kyr at a high relative velocity of 291 km/s.

Source: arxiv.org
voyager pioneer nasa space
Capturing Neutrinos from a Star’s Final Hours What happens on the last day of a massive star’s life? In the hours before the star collapses and explodes as a supernova, the rapid evolution of material in its core creates swarms of neutrinos....

Capturing Neutrinos from a Star’s Final Hours

What happens on the last day of a massive star’s life? In the hours before the star collapses and explodes as a supernova, the rapid evolution of material in its core creates swarms of neutrinos. Observing these neutrinos may help us understand the final stages of a massive star’s life — but they’ve never been detected.

[…]

For an imminent supernova at a distance of 1 kiloparsec, the authors find that the presupernova electron neutrino flux rises above the background noise from the Sun, nuclear reactors, and radioactive decay within the Earth in the final two hours before collapse.

Based on these calculations, current and future neutrino observatories should be able to detect tens of neutrinos from a supernova within 1 kiloparsec, about 30% of which would be beta-process neutrinos. As the distance to the star increases, the time and energy window within which neutrinos can be observed gradually narrows, until it closes for stars at a distance of about 30 kiloparsecs.

Are there any nearby supergiants soon to go supernova so these predictions can be tested? At a distance of only 650 light-years, the red supergiant star Betelgeuse should produce detectable neutrinos when it explodes — an exciting opportunity for astronomers in the far future!

Source: aasnova.org
betelgeuse astronomy astrophysics space
Chinese Academy of Sciences leads discovery of unpredicted stellar black hole Our Milky Way Galaxy is estimated to contain 100 million stellar black holes - cosmic bodies formed by the collapse of massive stars and so dense even light can’t escape....

Chinese Academy of Sciences leads discovery of unpredicted stellar black hole

Our Milky Way Galaxy is estimated to contain 100 million stellar black holes - cosmic bodies formed by the collapse of massive stars and so dense even light can’t escape. Until now, scientists had estimated the mass of an individual stellar black hole in our Galaxy at no more than 20 times that of the Sun. But the discovery of a huge black hole by a Chinese-led team of international scientists has toppled that assumption.

Source: eurekalert.org
black hole astrophysics astronomy space