Category Astronomy/Space

This artist’s impression shows several of the planets orbiting the ultra-cool red dwarf star TRAPPIST-1. New observations, when combined with very sophisticated analysis, have now yielded good estimates of the densities of all seven of the Earth-sized planets and suggest that they are rich in volatile materials, probably water. Credit: ESO/M. Kornmesser

A new study has found that planets orbiting the star TRAPPIST-1 are made mostly of rock, and some could hold more H2O than Earth. The planets’ densities suggest that some of them could have up to 5% of their mass in the form of water. The hotter planets closest to their parent star are likely to have dense steamy atmospheres and the more distant ones probably have icy surfaces...

This artist’s concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets’ diameters, masses, and distances from the host star, as of February 2018. Credit: NASA, JPL/Caltech, and R. Hurt and T. Pyle (IPAC)

Astronomers using Hubble have conducted the first spectroscopic survey of the Earth-sized planets (d, e, f, and g) within the habitable zone around the nearby star TRAPPIST-1. This study is a follow-up to Hubble observations made in May 2016 of the atmospheres of the inner TRAPPIST-1 planets b and c. Hubble reveals that at least 3 of the exoplanets (d, e, and f) do not seem to contain puffy, hydrogen-rich atmospheres similar to gaseous planets such as Neptune...

Artist’s impression of a “hot Jupiter”. Credit: Ricardo Cardoso Reis (CAUP)

Astronomers have detected “hot Jupiter” exoplanets transiting two distant stars. The newly found alien worlds, designated EPIC 229426032 b and EPIC 246067459 b, appear to be larger than it should be according to theoretical models. The finding is reported January 24 in a paper published on arXiv.org. The so-called inflated planets are those that expand in size when their parent stars are at the end of their lives. They have been known to astronomers for almost two decades, but it is still unclear what causes the inflation processes...

The quiescent galaxy eMACSJ1341-QG-1 as seen by the Hubble Space Telescope. The yellow dotted line traces the boundaries of the galaxy’s gravitationally lensed image. The inset on the upper left shows what eMACSJ1341-QG-1 would look like if we observed it directly, without the cluster lens. The dramatic amplification and distortion caused by the intervening, massive galaxy cluster (of which only a few galaxies are seen in this zoomed-in view) is apparent. Credit: Harald Ebeling, UH IfA

An international team of has discovered one of the most extreme instances of magnification by gravitational lensing...