With our continued failure to discover dark matter particles, it’s worth considering alternatives. While dark matter is the most widely supported model, the alternatives fall into two broad paths. One is that we should look to extended models of general relativity, such as conformal gravity. The other argues we should modify the very nature of Newtonian dynamics. The first approach tends to be popular with theorists since it focuses on an abstract theory in the same vein as Einstein’s original ideas. The second, often known as Modified Newtonian Dynamics, or MoND, tends to be more popular with observational astronomers.
Continue reading “Evidence for Modified Gravity Found in the Motions of Binary Stars”A Neutron Star is Unwinding a Companion Star
Close binary stars play several important roles in astronomy. For example, Type Ia supernovae, used to measure galactic distances, occur when a neutron star in a binary system reaches critical mass. These stars are also the source of x-ray binaries and microquasars, which help astronomers understand supermassive black holes and active galactic nuclei. But the evolutionary process of close binaries is still not entirely understood. That’s changing thanks in part to a new discovery of a close binary in its intermediate stage.
Continue reading “A Neutron Star is Unwinding a Companion Star”Each Planetary Nebula is Unique. Why Do They Look So Different?

When it comes to cosmic eye candy, planetary nebulae are at the top of the candy bowl. Like fingerprints—or maybe fireworks displays—each one is different. What factors are at work to make them so unique from one another?
Continue reading “Each Planetary Nebula is Unique. Why Do They Look So Different?”These Stars are Already Merging, but Their Future Will Be Catastrophic

Close-orbiting binaries are a ticking time bomb. Over time they spiral ever closer to each other until they merge in a cataclysmic explosion such as a supernova. But in the middle of their story, things can get interesting. Some stars collapse into a white dwarf before merging with their partner, others edge so close to each other that their surfaces touch for a time, becoming contact binaries before finally colliding. But one newly discovered binary system will have a wild ride before its final demise.
Continue reading “These Stars are Already Merging, but Their Future Will Be Catastrophic”Binary Dwarf Stars Found Orbiting Each Other Every 20 Hours. They Were Once Almost Touching

A team of astrophysicists has discovered a binary pair of ultra-cool dwarfs so close together that they look like a single star. They’re remarkable because they only take 20.5 hours to orbit each other, meaning their year is less than one Earth Day. They’re also much older than similar systems.
Continue reading “Binary Dwarf Stars Found Orbiting Each Other Every 20 Hours. They Were Once Almost Touching”Trading Spaces: How Swapping Stars Create Hot Jupiters
Star clusters tend to host more hot Jupiters than average, but why? A team of astronomers have proposed a new solution, and it involves a lot of swapping of stellar neighbors.
Continue reading “Trading Spaces: How Swapping Stars Create Hot Jupiters”Two Stars Orbiting Each Other Every 51 Minutes. This Can’t End Well

We don’t have to worry too much about our Sun. It can burn our skin, and it can emit potent doses of charged material—called Solar storms—that can damage electrical systems. But the Sun is alone up there, making things simpler and more predictable.
Other stars are locked in relationships with one another as binary pairs. A new study found a binary pair of stars that are so close to each other they orbit every 51 minutes, the shortest orbit ever seen in a binary system. Their proximity to one another spells trouble.
Continue reading “Two Stars Orbiting Each Other Every 51 Minutes. This Can’t End Well”Binary Stars Live Complicated Lives, Especially Near the End

We know what will happen to our Sun.
It’ll follow the same path other stars of its ilk follow. It’ll start running out of hydrogen, swell up and cool and turn red. It’ll be a red giant, and eventually, it’ll become so voluminous that it will consume the planets closest to it and render Earth uninhabitable. Then billions of years from now, it’ll create one of those beautiful nebulae we see in Hubble images, and the remnant Sun will be a shrunken white dwarf in the center of the nebula, a much smaller vestige of the luminous body it once was.
This is the predictable life the Sun lives as a solitary star. But what happens to stars that have a solar sibling? How would its binary companion fare?
Continue reading “Binary Stars Live Complicated Lives, Especially Near the End”Astronomers Have a New Way to Find Exoplanets in Cataclysmic Binary Systems

Have you heard of LU Camelopardalis, QZ Serpentis, V1007 Herculis and BK Lyncis? No, they’re not members of a boy band in ancient Rome. They’re Cataclysmic Variables, binary stars that are so close together one star draws material from its sibling. This causes the pair to vary wildly in brightness.
Can planets exist in this chaotic environment? Can we spot them? A new study answers yes to both.
Continue reading “Astronomers Have a New Way to Find Exoplanets in Cataclysmic Binary Systems”Hubble Sees a Surviving Companion Star After its Partner Went Supernova

When stars die they’re often not alone, and for the first time astronomers have found a companion to a supernova, lingering long after its sibling destroyed itself.
Continue reading “Hubble Sees a Surviving Companion Star After its Partner Went Supernova”