The release of the closest-ever images of the Sun understandably grabbed the headlines this week (you can read Richard A Lovetts report for Cosmos here) but there was other news of note. Here are some announcements that took our fancy.
Astronomers reported watching as a supermassive black holes own corona, the ultrabright, billion-degree ring of high-energy particles that encircles a black holes event horizon, was abruptly destroyed.
The cause is unclear, though they guess it was a star caught in the black holes gravitational pull. Like a pebble tossed into a gearbox, it may have ricocheted through the disc of swirling material, causing everything in the vicinity, including the coronas high-energy particles, to suddenly plummet into the black hole.
The result was a precipitous and surprising drop in the black holes brightness, by a factor of 10,000, in under just one year.
We expect that luminosity changes this big should vary on timescales of many thousands to millions of years, says Erin Kara, from Massachussetts Institute of Technlogy, but in this object, we saw it change by 10,000 over a year, and it even changed by a factor of 100 in eight hours, which is just totally unheard of and really mind-boggling.
Following the coronas disappearance, Kara and colleagues watched as the black hole began to slowly pull together material from its outer edges to reform its swirling accretion disc. In just a few months it was able to generate a new corona, with close to its original luminosity.
Journal abstract
Another group of astronomers at the Atacama Cosmology Telescope (ACT) in Chile took a fresh look at the oldest light in the Universe and, combining these observations with a bit of cosmic geometry suggest the Universe is 13.77 billion years old, give or take 40 million years.
The new estimate matches one provided by the Standard Model of the Universe and measurements of the same light made by the Planck satellite. This adds a fresh twist to an ongoing debate in the astrophysics community, says Simone Aiola, from the Centre for Computational Astrophysics in New York.
In 2019, a research team measuring the movements of galaxies calculated that the universe is hundreds of millions of years younger than the Planck team predicted. That discrepancy suggested that a new model for the Universe might be needed and sparked concerns that one of the sets of measurements might be incorrect.
Now weve come up with an answer where Planck and ACT agree, says Aiola. It speaks to the fact that these difficult measurements are reliable.
Journal abstract
Astrophysicists from Russia, South Korea and the US are suggesting that carbon is an indication of how long a comet has been in our Solar System; the less carbon, the longer its been in the proximity of the Sun.
The proof, they say, is the comet ATLAS (C/2019 Y4), which approached the Earth in May but disintegrated, displaying a major outbreak of the carbonaceous particles.
ATLAS was expected to be the brightest comet of 2020, visible from the Earth with a naked eye. However, instead of observing the comet itself, we witnessed its disintegration, says Ekaterina Chornaya, from Russias Far Eastern Federal University.
Luckily, we had begun photometric and polarimetric studies before the process started, and because of that, we are able to compare the composition of the coma before and after the disintegration.
The researchers say the polarimetric response of the particles from Comet ATLAS matches that of one of the brightest comets in the history of Earth Comet Hale-Bopp, or C/1995 O1.
Journal abstract
To finish, a couple of important dates were revealed this week.
The Japan Aerospace Exploration Agency (JAXA) and the Australian Space Agency jointly announced that the Hayabusa2 spacecraft containing samples from the asteroid Ryugu will arrive back on Earth in Woomera, South Australia, on 6 December this year. (You can read our most recent coverage of the mission here).
And NASA announced a new target date of 31 October 2021 for the launch of the James Webb Space Telescope from French Guiana. The ongoing coronavirus COVID-19 pandemic and technical challenges have required a move from the original planned launch in March.
See the rest here:
Spacewatch: Black holes, comets and key dates - Cosmos
- Rotational spectra of isotopic species of methyl cyanide, CH_3CN, in their ground vibrational states up to terahertz frequencies - November 8th, 2009 [November 8th, 2009]
- Cosmological parameter extraction and biases from type Ia supernova magnitude evolution - November 8th, 2009 [November 8th, 2009]
- Continuous monitoring of pulse period variations in Hercules X-1 using Swift/BAT - November 8th, 2009 [November 8th, 2009]
- Constraining the ortho-to-para ratio of H{_2} with anomalous H{_2}CO absorption - November 8th, 2009 [November 8th, 2009]
- A photometric and spectroscopic study of the new dwarf spheroidal galaxy in Hercules - Metallicity, velocities, and a clean list of RGB members - November 8th, 2009 [November 8th, 2009]
- Luminosities and mass-loss rates of SMC and LMC AGB stars and red supergiants - November 8th, 2009 [November 8th, 2009]
- Electron beam – plasma system with the return current and directivity of its X-ray emission - November 8th, 2009 [November 8th, 2009]
- The propagation of the shock wave from a strong explosion in a plane-parallel stratified medium: the Kompaneets approximation - November 8th, 2009 [November 8th, 2009]
- Analysis of hydrogen-rich magnetic white dwarfs detected in the Sloan Digital Sky Survey - November 8th, 2009 [November 8th, 2009]
- Letter: Centaurus A as TeV \gamma-ray and possible UHE cosmic-ray source - November 8th, 2009 [November 8th, 2009]
- Young pre-low-mass X-ray binaries in the propeller phase - Nature of the 6.7-h periodic X-ray source 1E 161348-5055 in RCW 103 - November 8th, 2009 [November 8th, 2009]
- Radiative rates and electron impact excitation rates for transitions in Cr VIII - November 8th, 2009 [November 8th, 2009]
- Solar granulation from photosphere to low chromosphere observed in Ba II 4554 Å line - November 8th, 2009 [November 8th, 2009]
- Does the HD 209458 planetary system pose a challenge to the stellar atmosphere models? - November 8th, 2009 [November 8th, 2009]
- Effect of asymmetry of the radio source distribution on the apparent proper motion kinematic analysis - November 8th, 2009 [November 8th, 2009]
- Destriping CMB temperature and polarization maps - November 8th, 2009 [November 8th, 2009]
- Search for cold debris disks around M-dwarfs. II - November 8th, 2009 [November 8th, 2009]
- Precise data on Leonid fireballs from all-sky photographic records - November 8th, 2009 [November 8th, 2009]
- An X-ray view of 82 LINERs with Chandra and XMM-Newton data - November 8th, 2009 [November 8th, 2009]
- Radio observations of ZwCl 2341.1+0000: a double radio relic cluster - November 8th, 2009 [November 8th, 2009]
- Candidate free-floating super-Jupiters in the young \sigma Orionis open cluster - November 8th, 2009 [November 8th, 2009]
- The metallicity gradient as a tracer of history and structure: the Magellanic Clouds and M33 galaxies - November 8th, 2009 [November 8th, 2009]
- XMMSL1 J060636.2-694933: an XMM-Newton slew discovery and Swift/Magellan follow up of a new classical nova in the LMC - November 8th, 2009 [November 8th, 2009]
- The inner rim structures of protoplanetary discs - November 8th, 2009 [November 8th, 2009]
- The solar Ba{\sf II} 4554 Å line as a Doppler diagnostic: NLTE analysis in 3D hydrodynamical model - November 8th, 2009 [November 8th, 2009]
- Magnetic evolution of superactive regions - Complexity and potentially unstable magnetic discontinuities - November 8th, 2009 [November 8th, 2009]
- Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530 - November 8th, 2009 [November 8th, 2009]
- PMAS optical integral field spectroscopy of luminous infrared galaxies - I. The atlas - November 8th, 2009 [November 8th, 2009]
- First AGILE catalog of high-confidence gamma-ray sources - November 8th, 2009 [November 8th, 2009]
- Radiative hydrodynamics simulations of red supergiant stars - I. interpretation of interferometric observations - November 8th, 2009 [November 8th, 2009]
- Extrasolar planets and brown dwarfs around A–F type stars - VII. \theta Cygni radial velocity variations: planets or stellar phenomenon? - November 8th, 2009 [November 8th, 2009]
- Cosmic rays and the magnetic field in the nearby starburst galaxy NGC 253 - II. The magnetic field structure - November 8th, 2009 [November 8th, 2009]
- Physical structure and water line spectrum predictions of the intermediate mass protostar OMC2-FIR4 - November 8th, 2009 [November 8th, 2009]
- The bright galaxy population of five medium redshift clusters - II. Quantitative galaxy morphology - November 8th, 2009 [November 8th, 2009]
- Dust in brown dwarfs and extra-solar planets - II. Cloud formation for cosmologically evolving abundances - November 8th, 2009 [November 8th, 2009]
- The quiet Sun magnetic field observed with ZIMPOL on THEMIS - I. The probability density function - November 8th, 2009 [November 8th, 2009]
- Complexity in the sunspot cycle - November 8th, 2009 [November 8th, 2009]
- Properties and nature of Be stars - 26. Long-term and orbital changes of \zeta Tauri - November 8th, 2009 [November 8th, 2009]
- The massive Wolf-Rayet binary LSS 1964 (=WR 29) - II. The V light curve - November 8th, 2009 [November 8th, 2009]
- Supernova progenitor stars in the initial range of 23 to 33 solar masses and their relation with the SNR Cassiopeia A - November 8th, 2009 [November 8th, 2009]
- The Hertzsprung-Russell Diagram of Star Clusters - November 8th, 2009 [November 8th, 2009]
- Table of the 10 Brightest stars within 10 Parsecs of the Sun - November 8th, 2009 [November 8th, 2009]
- The Hertzsprung-Russell Diagram of the Nearest Stars - November 8th, 2009 [November 8th, 2009]
- Magnitude and Color in Astronomy - November 8th, 2009 [November 8th, 2009]
- Stellar Types - November 8th, 2009 [November 8th, 2009]
- Brown Dwarfs - November 8th, 2009 [November 8th, 2009]
- Spotting the Minimum - November 8th, 2009 [November 8th, 2009]
- The Structure and Evolution of Brown Dwarfs - November 8th, 2009 [November 8th, 2009]
- No Bang from the Big Bang Machine - November 8th, 2009 [November 8th, 2009]
- The Sizes of the Stars and the Planets - November 8th, 2009 [November 8th, 2009]
- An Implausible Light Thrust - November 8th, 2009 [November 8th, 2009]
- the Masses of Degenerate Objects - November 8th, 2009 [November 8th, 2009]
- Degeneracy Pressure - November 8th, 2009 [November 8th, 2009]
- Introduction to Degenerate Objects - November 8th, 2009 [November 8th, 2009]
- The Radii of Degenerate Objects - November 8th, 2009 [November 8th, 2009]
- The Inevitability of Black Holes - November 8th, 2009 [November 8th, 2009]
- Scientific Pig-Out - November 8th, 2009 [November 8th, 2009]
- The Neutrino Cooling of Degenerate Dwarfs - November 8th, 2009 [November 8th, 2009]
- The Neutrino Cooling of Neutron Stars - November 8th, 2009 [November 8th, 2009]
- Overview of Supernovae - November 8th, 2009 [November 8th, 2009]
- Energetics of Thermonuclear Supernovae - November 8th, 2009 [November 8th, 2009]
- Thermonuclear Supernovae - November 8th, 2009 [November 8th, 2009]
- Nuclear Reactions in Thermonuclear Supernovae - November 8th, 2009 [November 8th, 2009]
- Core-Collapse Supernovae - November 8th, 2009 [November 8th, 2009]
- Neutrinos and SN 1987A - November 8th, 2009 [November 8th, 2009]
- Revealing the sub-AU asymmetries of the inner dust rim in the disk around the Herbig Ae star R Coronae Austrinae - December 13th, 2009 [December 13th, 2009]
- Probing the dust properties of galaxies up to submillimetre wavelengths - I. The spectral energy distribution of dwarf galaxies using LABOCA - December 13th, 2009 [December 13th, 2009]
- On the physical origin of the second solar spectrum of the Sc II line at 4247 Å - December 13th, 2009 [December 13th, 2009]
- On detecting the large separation in the autocorrelation of stellar oscillation times series - December 13th, 2009 [December 13th, 2009]
- Imaging the spotty surface of Betelgeuse in the H band - December 13th, 2009 [December 13th, 2009]
- Chandra observation of Cepheus A: the diffuse emission of HH 168 resolved - December 13th, 2009 [December 13th, 2009]
- A planetary eclipse map of CoRoT-2a - Comprehensive lightcurve modeling combining rotational-modulation and transits - December 13th, 2009 [December 13th, 2009]
- The chemical composition of carbon stars. The R-type stars - December 13th, 2009 [December 13th, 2009]
- Flow instabilities of magnetic flux tubes - IV. Flux storage in the solar overshoot region - December 13th, 2009 [December 13th, 2009]
- Fragmentation of a dynamically condensing radiative layer - December 13th, 2009 [December 13th, 2009]
- Temporal variations of the CaXIX spectra in solar flares - December 13th, 2009 [December 13th, 2009]
- Deuterium chemistry in the Orion Bar PDR - “Warm” chemistry starring CH_{2}D^+ - December 13th, 2009 [December 13th, 2009]
- Metal abundances in the cool cores of galaxy clusters - December 13th, 2009 [December 13th, 2009]
- The nature of the X-ray binary IGR J19294+1816 from INTEGRAL, RXTE, and Swift observations - December 13th, 2009 [December 13th, 2009]
- Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902 - December 13th, 2009 [December 13th, 2009]