Are These The Most Distant Galaxies Yet Seen?

Two fuzzy red objects in the early universe may be galaxies shining at us from only a few hundred million years after the Big Bang.

First Look at an Unusual Exoplanet’s Atmosphere

AAS Nova reports on a “super-puff” exoplanet that’s nearly 15 times less dense than Jupiter.

A visualization of HIP 41378 f, a gaseous planet located 347 light-years from Earth. NASA Exoplanet Catalog

Update From The Hope Probe At Mars

The United Arab Emirates’ Hope Probe, on a wide orbit around Mars, provides views of the dynamic Red Planet.

An artist's conception of the Hope Probe in orbit around the Red Planet. Hope / MBRSC / UAE Space Agency

New Planet Discovered Around Proxima Centauri, Star Nearest The Sun

A new instrument on a powerful telescope has enabled astronomers to discover another planet around our nearest stellar neighbor.

An artist's concept of Proxima d, the third candidate planet orbiting our nearest stellar neighbor, Proxima Centauri. ESO / L. Calçada

A Star Where It Shouldn't Be

There’s a massive star in our galaxy’s halo, far away from the usual star-forming haunts. How did it get there?

The O-type star HD 93521 is in the Milky Way's halo, far from the star-forming galactic plane

Interstellar Probe Proposed to Explore the Solar Neighborhood

A unique mission concept known as Interstellar Probe would venture beyond the solar system and probe our neighborhood environment.

BY: David Dickinson, Sky & Telescope

An exciting mission spanning the next half century of space exploration may leave Earth on a path out of the solar system in the next decade. Researchers from the Johns Hopkins University Applied Physics Laboratory revealed a formal proposal for the Interstellar Probe at the American Geophysical Union meeting held in New Orleans, Louisiana at the end of 2021. The mission would give us a big-picture view of the Sun's neighborhood.

Rethinking Ceres’s Physical Properties

Dawn’s images show that Ceres is a slightly ellipsoidal body measuring 965 by 891 km (600 by 554 miles). That’s smaller than we’d assumed, but not by much — so its overall density must be 2.16 g/cm3, about 4% higher than previous estimates. This increases the assumed percentage of water in the dwarf planet. “Ceres is a prototype wet protoplanet, intact from the earliest days of the solar system,” Russell concludes.

This artist concept shows NASA’s Dawn spacecraft above dwarf planet Ceres, as seen in images from the mission. Source: Sky & Telescope

Aurora on a Dwarf Star

Astronomers have detected what looks like auroral emission on an ultra-cool star.

This artist conception shows an aurora over the polar region of a brown dwarf. Astronomers have detected auroral emission in both radio and optical wavelengths on the dwarf LSR J1835+3259. In J1835’s case, the aurora probably doesn’t sit over the rotational pole, because the auroral emission varies with the star’s rotation period, suggesting it rotates at least partially in and out of view. The team also doesn’t know what shape the dwarf star’s auroras take; they might be more like an arc or hotspot than a ring. Source: Sky & Telescope

The Most Luminous Supernova

Astronomers have discovered an exploding star that belongs to the “superluminous” class, and it’s the most luminous one ever found.

Source: Sky & Telescope

Black Hole Too Big for its Breeches

A supermassive black hole in the early universe is at least 10 times too heavy for its host galaxy, raising questions about galaxy and black hole coevolution.

CID-947 is a supermassive black hole that’s visible across the observable universe because it’s actively gobbling down gas and spitting out radiation. It’s a classic quasar in every way except one: its supermassive black hole is too heavy for its galaxy.

Over the past decade, astronomers have discovered that supermassive black holes have a scaling relationship with their host galaxies: the more massive the black hole, the more massive the galaxy. On average, a supermassive black hole has a mass 1/100 to 1/1,000 times that of its host galaxy. Seemingly consistent relationships like this one have led astronomers to suspect that a black hole’s growth and its host galaxy’s growth are intertwined.

But CID-947 doesn’t lie anywhere near this relation. At 2 billion years after the Big Bang, this quasar only weighs eight times less than its host galaxy.

Kapteyn b: Exoplanet or Illusion?

 

Artistic representation of the potentially habitable exoplanet Kapteyn b as compared with Earth. Kapteyn b is represented here as an old and cold ocean planet with a network of channels of flowing water under a thin cloud cover. Source: Sky & Telescope

Supernova, Two Ways

Source: Sky & Telescope

This simulated image depicts the explosive death of a white dwarf as a Type Ia supernova with a stellar companion. When the supernova explodes (dark brown), its ejected material slams into the companion star (light blue). The violent collision produces an ultraviolet pulse, which is emitted from the conical hole carved out by the companion star.

Two new studies confirm that the white dwarfs that explode as Type Ia supernovae can approach death in two different ways.

For many years, astronomers have debated just how the white dwarf maxes out its mass. There are two scenarios: either it siphons gas from a “living” companion star until it just can’t swallow any more (called the single-degenerate model), or it merges with another dead star like itself (the double-degenerate model). The growing sense is that white dwarfs probably die both ways.

Two papers in the May 21st Nature support this suspicion. One reports an ultraviolet pulse from a supernova that, the authors say, is a telltale signal that the white dwarf was stealing material from a companion star. The other study finds no evidence for such a signal from three supernovae.