Category Astronomy/Space

Dust disk around the young star HD 142527 observed with ALMA.

Researchers have for the first time, achieved a precise size measurement of small dust particles around a young star through radio-wave polarization. ALMA’s high sensitivity for detecting polarized radio waves made possible this important step in tracing the formation of planets around young stars. Astronomers have believed that planets are formed from gas and dust particles, although the details of the process have been veiled. One of the major enigmas is how dust particles as small as 1 micrometer aggregate to form a rocky planet with a diameter of 10,000 km. Difficulty in measuring the size of dust particles has prevented astronomers from tracing the process of dust growth.

Akimasa Kataoka and his collaborators have theoretic...

This graphic shows the closest approaches of Cassini’s final two orbital phases. Ring-grazing orbits are shown in gray (at left); Grand Finale orbits are shown in blue. The orange line shows the spacecraft’s Sept. 2017 final plunge into Saturn. Image credit: NASA/JPL-Caltech

NASA’s Saturn-orbiting Cassini spacecraft has made its first close dive past the outer edges of Saturn’s rings since beginning its penultimate mission phase on Nov. 30. Cassini crossed through the plane of Saturn’s rings on Dec. 4 at 5:09 a.m. PST at a distance of ~57,000 miles above Saturn’s cloud tops. This is the approximate location of a faint, dusty ring produced by the planet’s small moons Janus and Epimetheus, and just 6,800 miles from the center of Saturn’s F ring.

About an hour prior to the ring-plane crossing...

A deep photographic image of M83 taken using the UK Schmidt Telescope by Malin & Hadley (1997, figure reproduced with permission) where the white scale bar corresponds to 30 arcmin. The northern stream appears not to be associated with dw1335-29, circled in red. Credit: Carrillo et al., 2016.

M83, Southern Pinwheel Galaxy has a newly found dwarf satellite 85,000 light years from its host. This satellite galaxy was designated dw1335-29 and could be an irregular or a transition dwarf. Messier 83 is one of the closest and brightest barred spiral galaxies. It is located about 15 million light years away in the constellation Hydra. Finding new satellites of galaxies beyond the Local Group such as Messier 83 could provide essential insights on galaxy formation in a cosmological context.

In 2015,...

This NASA/ESA Hubble Space Telescope image of comet 73P/Schwassmann-Wachmann 3 disintegrating in 2006 shows the tails and comas of the individual pieces of the comet; new research on comet composition included infrared spectrography of this comet during its breakup. Credit: NASA, ESA, H. Weaver (APL), M. Mutchler and Z. Levay (STScI)

A new study has revealed similarities and relationships between certain types of chemicals found on 30 different comets, which vary widely in their overall composition compared to one another. The research is part of ongoing investigations into these primordial bodies, which contain material largely unchanged from the birth of the solar system some 4.6 billion years ago.

By studying the composition of hazy comas and tails of these comets, researchers found tha...