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Binary and Multi-Star Systems

A binary is a pair of stars that orbit each other. A multi-star system consists of three or more stars. The stars in a binary or a multi-star system all formed from a single cloud of gas and dust, so they are true “siblings.”


Libra, the Scales

Libra, the Scales October 4, 2011

Radio Programs

Naming Rights Picking names for distant planets September 7, 2023

Doomed Companions Giant stars that are doomed September 4, 2023

Heartbeat Stars The shared “heartbeats” of binary stars September 2, 2023

Moon and Spica A good “semi-quincentennial” star August 20, 2023

Targets of Interest Interesting signals from the stars August 14, 2023

Binary Stars Stars with traveling companions July 30, 2023

The Stinger The scorpion’s bright stinger July 16, 2023

Equuleus Drawing up a little horse July 15, 2023

Double Parents A planet that’s been through a lot July 14, 2023

Explode or Not? A pair of stars with an unclear fate July 9, 2023

Moon and Regulus A flashy star and its ignored siblings June 22, 2023

Dubhe A double double in the Big Dipper June 10, 2023

Noisy Mergers Defying gravity — for a little while May 8, 2023

Rasalhague A preview of coming attractions May 7, 2023

Moon and Antares Rolling through some stellar bowling pins May 6, 2023

Dead and Dying A dead and dying star system April 6, 2023

Moon and Spica Studying a star that no one’s seen April 5, 2023

Moon, El Nath, and Mars An intriguing stellar giant March 27, 2023

Messier 3 Reinvigorating some old stars March 15, 2023

Running Away A star that’s running away from its birthplace February 26, 2023

Alpheratz Boosting a star’s brightness February 19, 2023

Procyon “Weighty” differences between stars February 18, 2023

Close Black Hole Black holes get closer February 12, 2023

Moon and Spica A complicated star system February 10, 2023

Beta Monocerotis A beautiful set of triplets February 9, 2023

Betelgeuse II A runaway supergiant January 10, 2023

Moon and Gemini Twins that are more than pretty faces January 7, 2023

Algol The perfect star for Halloween October 30, 2022

Capricornus The weird and wonderful sea-goat October 9, 2022

Almach A colorful “double” quartet October 2, 2022

Moon and the Scorpion Doomed stars in the scorpion September 30, 2022

Micronovae Small big blasts from a star September 8, 2022

Sigma Scorpii Impressive stars near the scorpion’s heart August 27, 2022

Delta Cygni Spreading out a stellar trio July 23, 2022

SS 433 A “micro-quasar” in the eagle July 21, 2022

Overdue Eruption A tardy stellar outburst July 13, 2022

Scorpius X-1 Brightest and brightest in the scorpion July 12, 2022

Moon and the Sickle A perilous position for the Moon July 2, 2022

Super Superflares The superstar of superflares June 15, 2022

Doomed Stars Doomed stars with a bright future June 11, 2022

Moon and Spica Living under two brilliant suns June 9, 2022

Deneb Algedi A planet “tails” the sea goat May 28, 2022

Antlia Stars that share a warm embrace April 10, 2022

Impressive Twins Impressive stellar twins April 2, 2022

Luhman 16 Close neighbors with a familiar look March 27, 2022

Moon and Spica “Wiggle room” in the fate of a star March 19, 2022

Moon and Regulus Four stars for the price of one March 15, 2022

Moon and Antares A brilliant demise for a bright star February 23, 2022

Moon and Gemini A set of “twins” that don’t match February 13, 2022

‘Nu’ Stars “New” stars for the big dog February 5, 2022

Colorful Butterfly Sculpting a cosmic butterfly January 29, 2022

Zubenelgenubi Two names for four stars January 25, 2022

Procyon A before-and-after pair of stars January 22, 2022

Moon and the Twins A companion for a “twin” star January 17, 2022

Busy Binary A busy star system for the unicorn January 7, 2022

Moon and Regulus Looking for a faint companion November 25, 2021

Capella Lining up a pair of bright stars November 21, 2021

Moon and Regulus A star that’s barely holding it together October 2, 2021

The Little Horse Drawing up a little horse September 26, 2021

Dabih Many names for a crowded star system September 2, 2021

Moon and Zubenelgenubi Stepping back in time August 14, 2021

IC 10 X-1 A bright, dark star system July 22, 2021

Moon and the Scorpion The head of the scorpion gets brighter July 19, 2021

Moon and Spica Looking into a well-studied star July 16, 2021

Seeing Sextuple Counting the stars in a rare system July 9, 2021

Seeing Double Seeing double in the evening sky June 5, 2021

Extreme Black Widow A dead star destroys its mate June 4, 2021

Cygnus X-1 A black hole gets heavier June 3, 2021

Alphecca Stellar siblings with different futures May 21, 2021

Tatooine-Plus Stars galore for a unique planet May 7, 2021

Setting the Stage Setting the stage for a big outburst May 1, 2021

T Pyxidis A star that’s not a good neighbor April 14, 2021

Cat’s Eye Sculpting a stellar work of art April 10, 2021

Gamma Virginis A pair of nearly identical twins April 4, 2021

Moon and Spica An amazing star system follows the Moon March 28, 2021

Seven Siblings A sprawling family of seven stars March 27, 2021

Moon and Gemini Sextuplets in the night sky February 23, 2021

Blue Stragglers Rejuvenating some old stars January 19, 2021

Procyon Whittling away at the stars January 17, 2021

Orion’s Head Topping off the hunter January 3, 2021

Moon and Regulus The lion’s quadruple heart December 5, 2020

Ancient Planet The life of an ancient planet November 22, 2020

Andromeda A colorful quartet of stars November 4, 2020

Capella A pair of bright, “puffy” stars October 25, 2020

VV Cephei A big, messy star system October 3, 2020

Moon and Aldebaran A confusing relationship August 12, 2020

The Arteries The strong arteries of the scorpion August 6, 2020

Blowing Off Steam A star that likes to blow off steam August 5, 2020

Epsilon Lyrae Seeing double in the summer sky July 26, 2020

Red Square A star’s beautiful demise July 7, 2020

Faint Neighbors Faint neighbors in the swan July 3, 2020

Alpha Centauri Putting three stars on the scales June 9, 2020

Heavyweight Merger A merger of heavyweight stars June 2, 2020

Twin Jewels The jewels of the northern crown May 24, 2020

‘Sailing’ Stars “Sailing” along with the crow May 19, 2020

The Keystone Four stars, four stories May 17, 2020

Speedy Stars Sending a star on a wild ride May 14, 2020

Cor Caroli Stirring up the Heart of Charles March 22, 2020

Jumpy Stars The busy feet of the great bear March 15, 2020

Mintaka Big stars with bigger futures March 13, 2020

NGC 246 Sculpting a bright skull February 26, 2020

Contact Binaries Stars that are especially close February 21, 2020

Moon and Regulus A star that’s more than meets the eye February 9, 2020

Dubhe Pulling apart the Big Dipper February 2, 2020

Fornax Heating up a faint patch of sky January 24, 2020

Dog Stars A pair of dogs in the night sky January 18, 2020

Moon and Spica An unlikely place for planets January 17, 2020

Accretion Disks Brightening up a black hole January 14, 2020

Double Horn The “double” horn of the bull January 8, 2020

Moon and Aldebaran Looking for faint companions January 7, 2020

Moon and Spica A bright star with a brighter future November 22, 2019

“Double” Foot The bright foot of a celestial twin November 12, 2019

Capella Measuring a double binary star system October 16, 2019

Beta Lyrae A big shift in a binary star system October 4, 2019

Double Black Holes Not seeing double stars September 27, 2019

Black Holes Galore Black holes in the Milky Way September 26, 2019

The Dolphin’s Snout The dolphin’s contrasting colors July 27, 2019

Cygnus X-1 A giant star vanishes from view July 11, 2019

Rasalhague The “dizzy” head of the serpent bearer June 30, 2019

Messier 10 Rejuvenation for some old stars June 19, 2019

Moon and Spica A pair of bright stellar “eggs” June 12, 2019

Moon and Antares One of the biggest of the big April 21, 2019

Moon and Regulus A stellar flip-flop March 18, 2019

Black Widows Dead stars with dying mates March 4, 2019

Alphard A mystery in the water snake February 23, 2019

The Twins A goodly supply of twins January 26, 2019

Navi A bright, busy star system January 21, 2019

Collision Zones A big impact around a young star October 15, 2018

Capricornus Following the sea-goat October 9, 2018

Fomalhaut System A star with distant relatives September 22, 2018

Symbiotes A busy “symbiotic” star September 19, 2018

61 Cygni Zeroing in on a nearby star August 4, 2018

Albireo The swan’s colorful beak July 28, 2018

Moon and Companions Siblings that have an impact July 19, 2018

16 Cygni Two Sun-like stars in a single system July 3, 2018

Building Big Black Holes Building bigger black holes June 26, 2018

Future Supernova A busy star with a violent future June 5, 2018

VW Cephei Two stars in a tight embrace May 19, 2018

Future Cannibal A future act of stellar cannibalism May 6, 2018

Moon and Spica Two stars with different fates April 27, 2018

Cor Caroli Dark blemishes on a big star April 22, 2018

Bright Quartet A fascinating stellar quartet April 11, 2018

Procyon A star at a transition point January 20, 2018

Balancing Planets Flanking the scorpion’s claw December 29, 2017

Stellar Kiss Two stars that may become one December 28, 2017

Capella Bright stars with a bright future November 25, 2017

Mirfak Looking for a companion October 30, 2017

Capricornus The weird and wonderful sea-goat October 13, 2017

Double Double Doubling up on stars in the harp September 30, 2017

V404 Cygni A binge-eating black hole September 1, 2017

Wild Duck Cluster Measuring the age of some wild ducks August 27, 2017

Delta Cygni Spreading out a stellar trio July 31, 2017

Sigma Scorpii Impressive stars near the scorpion’s heart July 30, 2017

Black Widows Celestial creepy-crawlies July 21, 2017

Scorpion’s Tail The scorpion’s fearsome tail July 13, 2017

Scorpion’s Head An arachnid with a case of the “bighead” July 12, 2017

Zapped! A dead star zaps a close companion July 5, 2017

Red Nova An exploding star turns red June 28, 2017

Orange Triplets Three orange stars for the price of one June 24, 2017

Big Changes A Sun-like star picks up the pace June 16, 2017

Moon and Spica Learning about a bright stellar duo June 4, 2017

Kornephoros The leading light of the club bearer May 31, 2017

More Northern Crown The “re-death” of two dead stars May 28, 2017

Northern Crown Crowning the northern sky May 27, 2017

Doomed Star A star faces a fate worse than death May 9, 2017

Moon and Spica Different fates for stellar siblings May 8, 2017

The Most Beautiful The “most beautiful” stars April 30, 2017

Moon and Regulus A star that’s older than it looks April 6, 2017

Cor Caroli Twins with different life expectancies March 25, 2017

Giant Cannibal A giant star becomes a cannibal March 16, 2017

Kicked Out Two stars get kicked out of the nest February 18, 2017

Dubhe Two suns in an alien sky February 12, 2017

Heartbeat Stars Watching stars change shape February 6, 2017

Misaligned Disks Looking into the future of young stars February 3, 2017

Lepus Chasing down a celestial rabbit January 28, 2017

More Fornax Drinking from the fountain of youth January 20, 2017

Moon and Regulus Learning about a familiar star January 14, 2017

Castor A miniature “star cluster” January 7, 2017

Featured Images

james webb space telescope view of a binary star system producing rings of dust

Making Rings October 16, 2022

Radio image of SS 433, a micro-quasar powered by a black hole

Cosmic Corkscrews July 21, 2022

james webb telescope view of a planetary nebula

Dying Beauty July 13, 2022

Chart showing all star systems within 15 light-years of Earth

The Neighborhood January 11, 2022

artist's concept of cygnus X-1

Needy Companion June 3, 2021

false-color image of Skull Nebula

Red Skull November 18, 2020

artist's concept of a system with a white dwarf and a brown dwarf

Hot and Cold August 22, 2020

ngc 246, the skull nebula

Skull Nebula February 26, 2020

contact binary

Making Contact February 21, 2020

a nebula surrounds a dying star

Beautiful Demise February 8, 2020

Accretion disk around a black hole

Circling Darkness January 14, 2020

Simulation of two merging black holes

Double Darkness September 27, 2019

X-ray image of light echoes from V404 Cygni

Echoes of a Black Hole August 28, 2019

The star system Apep, which may detonate as a gamma-ray burst

Spooky Star August 15, 2019

Moon and Spica, evening of June 12, 2019

Double Giant June 12, 2019


The Herdsman May 9, 2019

Artist's concept of two neutron stars merging to make a black hole

Violent Merger September 14, 2018


Colorful Beak July 28, 2018

Orion Nebula and the star system Iota Orionis

Mismatched Twins March 23, 2018

Artist's concept of AR Scorpii

Pulsing Corpse July 5, 2017

False-color image of the Boomerang Nebula, which is being created by a dying star

Cold Death June 7, 2017

HST view of 47 Tucanae

Star Globe May 9, 2017

Artist's concept of 47 Tucanae X9, a likely black hole-white dwarf binary

Living Dangerously March 16, 2017

X-Ray image of VLA J2130+12

Slow Eater December 15, 2016

Hubble Space Telescope view of the Gliese 229 system

Faint Neighbors February 7, 2016

X-ray energy forms expanding rings around the black hole V404 Cygni

Big Gulp Aftermath September 15, 2015

The system V664 Cassiopeia is creating a planetary nebula

Bread Crumbs July 23, 2015

Artist's concept of Alpha Centauri A and B, plus a planet

Busy Neighbor May 25, 2015

Artist's concept of MY Camelopardalis, a contact binary star system

Close Twins March 15, 2015