“Heracles” –Fossil Galaxy Seeded the Infant Milky Way With Alien Stars

Milky Way Halo



Astronomers have excavated a galactic tomb –a stunning picture of our home galaxy’s successive mergers with neighboring galaxies. Recent discoveries by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) revealed the “archaeological” record embedded in hundreds of thousands of stars that unveiled the assembly history and evolution of our Milky Way Galaxy.


“Vampire” Two-Star System: Creates the Illusion of a Black Hole Closest to Earth



The first black hole to be discovered was Cygnus X-1 in 1964. It comprises a black hole and a blue supergiant star orbiting each other. The black hole is accreting from the wind of the blue supergiant, forming a hot disk around the black hole that emits powerful X-rays. The mass of the invisible  companion is calculated to be 8-10 solar masses, much too large to be a neutron star.


“Everything on a Gigantic Scale” – Alien Planet Imaged Orbiting b Centauri’s Massive Two-Star System

b Centauri


“The planet in b Centauri is an alien world in an environment that is completely different from what we experience here on Earth and in our Solar System,” explains co-author Gayathri Viswanath, a researcher in exoplanet detection at Stockholm University. “It’s a harsh environment, dominated by extreme radiation, where everything is on a gigantic scale: the stars are bigger, the planet is bigger, the distances are bigger.”


Triple-Star System of Eta Carinae – Five Million Times Brighter than Our Sun


Eta Carinae Hubble image


The young star Eta Carinae –one of the most massive in the Milky Way – survived a titanic eruption 170 years ago. Although located relatively far away from Earth (about seven thousand light-years away, as compared with the average distance of naked-eye stars of about a thousand light-years), it can be seen easily by people in the southern hemisphere because it is extraordinarily  bright—about five million times more luminous than our Sun.


At Dawn of the Human Species –Milky Way’s Central Black Hole Slingshotted a Star at a Blistering 6 Million KPH


Supermassive Black Hole


“Seeing this star is really amazing as we know it must have formed in the galactic center, a place very different to our local environment. It is a visitor from a strange land,” said NASA Hubble Fellow Ting Li with the Carnegie Observatories and Princeton University, about the discovery of the ultrafast star, S5-HVS1 in 2019, traveling at a blistering 6 million km/h. The doomed star was slingshotted by the supermassive black hole at the heart of the Milky Way five million years ago at the dawn of the human species.


Fast Facts About Moving Groups of Stars in the Milky Way


Beta Pictoris


Stars are born in nurseries with a collection of siblings that range in mass but share chemical compositions and dynamic histories.  As time passes, the tightly bound nursery that they were born inside dissipates with increased gravitational interactions from outside sources (passing giant molecular clouds or stars).  One form of evolved stellar nurseries is called a “moving group”.  In this article I will review four fast facts about these loosely bound collections of co-moving, co-evolving stars.

Jackie Faherty, astrophysicist at the American Museum of Natural History and Editor at The Daily Galaxy.