News (Page 798)

Astronomers detect low-mass brown dwarf around A-type main-sequence star Using HATSouth Exoplanet Survey, an international group of astronomers has discovered a low-mass brown dwarf transiting an A-type main-sequence star. The newly detected brown dwarf, designated HATS-70b, is the first such object found around a star of this type. The finding is detailed in a paper published November 16 on arXiv.org. phys.org Go to SourceRead More →

How do stellar binaries form? Most stars with the mass of the sun or larger have one or more companion stars, but when and how these multiple stars form is one of the controversial central problems of astronomy. Gravity contracts the natal gas and dust in an interstellar cloud until clumps develop that are dense enough to coalesce into stars, but how are multiple stars fashioned? Because the shrinking cloud has a slight spin, a disk (possibly a preplanetary system) eventually forms. In one model of binary star formation, this disk fragments due to gravitational instabilities, producing a second star. The other model argues thatRead More →

LCO and NASA’s Kepler work together to determine origins of supernova Astronomers at Las Cumbres Observatory (LCO) are part of an international team of scientists who used NASA’s Kepler satellite to catch a rare glimpse of a Type Ia supernova minutes after explosion. The supernova, named SN 2018oh, was brighter than expected over the first few days. The increased brightness is an indication that it slammed into a nearby companion star. This adds to the growing body of evidence that some, but not all, of these thermonuclear supernovae have a large companion star that triggers the explosion. phys.org Go to SourceRead More →

A study of almost 2600 IAU members shows that astronomers have a remarkable drive for public engagement Because of the ubiquitous nature of its questions and the stunning insights into the nature of the Universe, astronomy has often been thought of as appealing and the natural science with the most far-reaching popularisation efforts. A recently published study of the outreach activities of IAU members, Bustling public communication by astronomers around the world driven by personal and contextual factors, has shown that professional astronomers may be engaging with the public more than scientists in any other field. phys.org Go to SourceRead More →

Fabrication of powerful telescope begins Fabrication of the Cerro Chajnantor Atacama Telescope-prime (CCAT-p), a powerful telescope capable of mapping the sky at submillimeter and millimeter wavelengths, has now begun, marking a major milestone in the project. phys.org Go to SourceRead More →

Study witnesses first moments of star dying in finest detail An international research team including The Australian National University (ANU) has used the Kepler space telescope in coordination with ground-based telescopes to witness the first moments of a star dying in unprecedented detail. phys.org Go to SourceRead More →

First high-resolution look at the quiet Sun with ALMA at 3 mm Observations of the radio continuum at millimeter (mm) wavelengths provide a unique chromospheric diagnostic. The quiet sun mm-wavelength emission mechanism is free-free and electrons are almost always in local thermodynamic equilibrium (e.g. Shibasaki et al. 2011 and Wedemeyer et al. 2016). The availability of mm-wavelength solar observations with ALMA can advance our knowledge on the chromosphere because of the instrument’s unique spatial resolution and sensitivity. In a previous study, the researchers used ALMA full-disk (FD) commissioning data to study the quiet sun under low resolution. However, publications of results from ALMA high-resolution quietRead More →

Magnetic fields found in a jet from a baby star An international research team led by Chin-Fei Lee in the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) has made a breakthrough observation with the Atacama Large Millimeter/submillimeter Array (ALMA), confirming the presence of magnetic fields in a jet from a protostar. Jets are believed to play an important role in star formation, enabling the protostar to accrete mass from an accretion disk by removing angular momentum from the disk. It is highly supersonic and collimated, and predicted in theory to be launched and collimated by magnetic fields. The finding supports the theoretical prediction andRead More →

Black hole ‘donuts’ are actually ‘fountains’ Based on computer simulations and new observations from the Atacama Large Millimeter/submillimeter Array (ALMA), researchers have found that the rings of gas surrounding active supermassive black holes are not simple donut shapes. Instead, gas expelled from the center interacts with infalling gas to create a dynamic circulation pattern, similar to a water fountain in a city park. phys.org Go to SourceRead More →

Newly discovered supernova may rewrite exploding star origin theories A supernova discovered by an international group of astronomers has provided an unprecedented look at the first moments of a violent stellar explosion. The team, led by the University of Hawaiʻi (UH) Institute for Astronomy’s (IfA) Ben Shappee and Carnegie Observatories’ Tom Holoien, found a mysterious signature in the light from the explosion’s first hours. Their findings are published in a trio of papers in the Astrophysical Journal. phys.org Go to SourceRead More →