Bright X-ray galactic nuclei

All massive galaxies are believed to host supermassive black holes (SMBH) at their centers that grow by accreting mass from their environment. The current picture also imagines that the black holes grow in size as their host ...

Discovering a brown dwarf binary star with microlensing

Brown dwarfs are stars less massive than the sun and unable to burn hydrogen. They comprise (at least in mass) a bridge between planets and stars, and astronomers think that they form and evolve in ways different from either ...

An exoplanet with an 11-hour orbit

The Transiting Exoplanet Survey Satellite (TESS) was launched on April 18 of last year with the primary objective of discovering transiting planets smaller than Neptune around stars bright enough for spectroscopic investigations ...

Energetic particles can bombard exoplanets

TRAPPIST-1 is a system of seven Earth-sized worlds orbiting an ultra-cool dwarf star about 120 light-years away. The star, and hence its system of planets, is thought to be between five-to-ten billion years old, up to twice ...

The disintegrating exoplanet K2-22b

Exoplanet surveys have yielded many surprises over the years, and the discovery of "disintegrating" exoplanets was one of them. These are planets that produce asymmetric shapes in the dips of the light curves seen as they ...

Making stars when the universe was half its age

The universe is about 13.8 billion years old, and its stars are arguably its most momentous handiwork. Astronomers studying the intricacies of star formation across cosmic time are trying to understand whether stars and the ...

Chandra detection of a circumnuclear torus

Most galaxies host supermassive black holes at their nuclei, each with millions or billions of solar-masses of material. There is thought to be a torus of dust and gas around the black holes, and an accreting disk that becomes ...

A new neptune-size exoplanet

The remarkable exoplanet discoveries made by the Kepler and K2 missions have enabled astronomers to begin to piece together the history of the Earth and to understand how and why it differs from its diverse exoplanetary cousins. ...

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 ...

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