A blue supergiant (BSG) is a hot, luminous star, often referred to as an OB supergiant. They are usually considered to be those with luminosity class I and spectral class B9 or earlier, although sometimes A-class supergiants are also deemed blue supergiants.
In the fields of Big Bang theory and cosmology, reionization is the process that caused electrically neutral atoms in the universe to reionize after the lapse of the "dark ages".
GQ Lupi b, or GQ Lupi B, is a possible extrasolar planet, brown dwarf or sub-brown dwarf orbiting the star GQ Lupi. Its discovery was announced in April 2005, less than a month before the full confirmation of 2M1207b was announced. Along with 2M1207b, this was one of the first extrasolar planet candidates to be directly imaged. The image was made with the European Southern Observatory's VLT telescope at the Paranal Observatory, Chile on June 25, 2004.
A yellow hypergiant (YHG) is a massive star with an extended atmosphere, a spectral class from A to K, and, starting with an initial mass of about 20–60 solar masses, has lost as much as half that mass. They are amongst the most visually luminous stars, with absolute magnitude (MV) around −9, but also one of the rarest, with just 20 known in the Milky Way and six of those in just a single cluster. They are sometimes referred to as cool hypergiants in comparison with O- and B-type stars, and sometimes as warm hypergiants in comparison with red supergiants.
In cosmology, galaxy filaments are the largest known structures in the universe, consisting of walls of galactic superclusters. These massive, thread-like formations can commonly reach 50/h to 80/h megaparsecs —with the largest found to date being the Hercules-Corona Borealis Great Wall at around 3 gigaparsecs (9.8 Gly) in length—and form the boundaries between voids. Due to the accelerating expansion of the universe, the individual clusters of gravitationally bound galaxies that make up galaxy filaments are moving away from each other at an accelerated rate; in the far future they will dissolve.
MACS0647-JD is a galaxy with a redshift of about z = 10.7, equivalent to a light travel distance of 13.26 billion light-years. If the distance estimate is correct, it formed about 427 million years after the Big Bang.
MACS J0647.7+7015 is a galaxy cluster with a redshift z = 0.592, located at J2000.0 right ascension 06h 47m 42s declination +70° 15′. It lies between the Big Dipper and Little Dipper in the constellation Camelopardalis. It is part of a sample of 12 extreme galaxy clusters at z > 0.5 discovered by the MAssive Cluster Survey (MACS).
SN Refsdal is the first detected multiply-lensed supernova, visible within the field of the galaxy cluster MACS J1149+2223. It was named after Norwegian astrophysicist Sjur Refsdal, who, in 1964, first proposed using time-delayed images from a lensed supernova to study the expansion of the universe. The observations were made using the Hubble Space Telescope.
A circumplanetary disk is a torus, pancake or ring-shaped accumulation of matter composed of gas, dust, planetesimals, asteroids or collision fragments in orbit around a planet. They are reservoirs of material out of which moons may form. Such a disk can manifest itself in various ways.
WHL0137-LS, also known as Earendel, is a star located in the constellation of Cetus. Discovered in 2022 by the Hubble Space Telescope, it is the earliest and most distant known star, at a comoving distance of 28 billion light-years. The previous farthest known star, MACS J1149 Lensed Star 1, also known as Icarus, at a comoving distance of 14.4 billion light-years, was discovered by Hubble in 2018. Stars like Earendel can be observed at cosmological distances thanks to the large magnification factors afforded by gravitational lensing, which can exceed 1,000. Other stars have been observed through this technique, such as Godzilla.
Godzilla is a variable star in the Sunburst galaxy at redshift z = 2.37, observed through the gravitational lens PSZ1 G311.65-18.48. It was originally identified in the NW arc as a possible transient event in images taken with the Hubble Space Telescope (HST).
The Sunburst galaxy is a strongly magnified galaxy at redshift z=2.38 behind the galaxy cluster PSZ1 G311.65-18.48.
UNCOVER-z13 is a high-redshift Lyman-break galaxy discovered by the James Webb Space Telescope (JWST) during NIRCam imaging for the JWST Ultradeep NIRSpec and NIRCam Observations before the Epoch of Reionization (UNCOVER) project on November 14, 2023. UNCOVER-z13 is within Abell 2744 supercluster in the constellation Sculptor.
UNCOVER-z12 is a high-redshift Lyman-break galaxy discovered by the James Webb Space Telescope (JWST) during NIRCam imaging for the JWST Ultradeep NIRSpec and NIRCam Observations before the Epoch of Reionization (UNCOVER) project in November 2023. UNCOVER-z12 is within the Abell 2744 supercluster in the constellation Sculptor. It is the 5th-most distant object ever discovered as of 2024, and is estimated to be 32.21 giga-lightyears from Earth.
Mothra, or EMO J041608.838-240358.60, is a binary system with a possible transient, in the constellation of Eridanus. Mothra is in the galaxy cluster MACS J0416.1-2403, nicknamed the "Christmas Tree Galaxy Cluster".
UNCOVER-BD-1 is a distant brown dwarf. It is the most distant T dwarf discovered to date.
