Astronomy

Betelgeuse, Betelgeuse! The red supergiant that marks Orion’s left shoulder may have a tiny, unseen companion.

Two independent studies found evidence of a star about the same mass as the sun, orbiting Betelgeuse about once every 2,100 days.

“It was very surprising,” says astrophysicist Morgan MacLeod of the Harvard & Smithsonian Center for Astrophysics in Cambridge, Mass. If the star is real, “it’s kind of hidden right there in plain sight.”

MacLeod and colleagues linked a six-year cycle of Betelgeuse brightening and dimming to a companion star tweaking its orbit, in a paper submitted to arXiv.org September 17. MacLeod examined global, historical measurements dating back to 1896. More

While SpaceX’s Starlink satellites are enabling internet access and cell phone communications around the globe, they’re also posing a threat to radio astronomy, a new study suggests.

In some wavelength bands, unintended leakage of electromagnetic radiation from the latest generation of the satellites is more than 30 times brighter than emissions from previous versions, Cees Bassa, a radio astronomer at the Netherlands Institute for Radio Astronomy in Dwingeloo and his colleagues report September 18 in Astronomy & Astrophysics. Because the latest generation of Starlink satellites will orbit as many as 100 kilometers lower than earlier satellites, they’ll seem even brighter to ground-based telescopes. Overall, their brightness could easily mask observations of dimmer objects like distant galaxies or stars. More

Contrary to a previous report, there’s no evidence of an intermediate-mass black hole in Omega Centauri, the Milky Way’s most massive and luminous globular star cluster, a new study finds. Instead, a hive of much smaller black holes diving into and out of the tightly packed star cluster’s center can explain the movement and distribution of its many ancient stars.

“What we found in our analysis is that the data favor an extended component [of stellar-mass black holes] as opposed to an intermediate-mass black hole,” says Andrés Bañares-Hernández, an astronomer at the Instituto de Astrofísica de Canarias in La Laguna, Spain. Some 10,000 to 20,000 stellar-mass black holes — adding up to between 200,000 and 300,000 times the mass of the sun — that are spread around the center of the star cluster can explain the observations, he says. More

One of the farthest known quasars seems to have shut down the creation of new stars in all the galaxies within its vicinity.

A quasar is a powerful source of light, created by torrid gas orbiting a gargantuan black hole at the center of a galaxy. The intense radiation from one quasar, named VIK J2348-3054, has probably stopped star formation at least 16 million light-years away from itself, astronomer Trystan Lambert and colleagues report in a paper to appear in Astronomy and Astrophysics. More

To leave a lasting trail, meteors need to aim low. A new survey of shooting stars shows that meteors that blaze through 90 kilometers up in the sky leave a persistent afterglow, unlike those that burn up at greater heights.

Meteors are normally blink-and-you’ll-miss-it events. A particle of space dust leaves a fiery trail of light as it zips through the atmosphere, and then it’s gone. But sometimes, a meteor leaves a lingering afterglow. Astronomers have noted these persistent trains for more than a century, but questions remained about their origins. More

The star marking true north is a good deal heavier than we thought.

The North Star is 5.1 times as massive as the sun, astronomers report in work submitted July 12 to arXiv.org. That value, calculated from the motion of a much fainter star that orbits the luminary, is nearly 50 percent heavier than a recent estimate of 3.45 solar masses.

Mass profoundly affects stellar life: The more mass a star has, the faster it burns its fuel and the sooner it dies. The earlier mass estimate had suggested that the North Star, also known as Polaris, is roughly 100 million years old (SN/12/2/16). The new estimate means the star formed more recently than this, but no one has yet calculated a revised age. More

For the first time, astronomers have spotted a middleweight black hole in the nearby universe. The discovery could help solve the riddle of how even heftier black holes form and grow up with their host galaxies.

The black hole, which sits about 16,000 light-years from Earth in the center of star cluster Omega Centauri, is at least 8,200 times as massive as the sun, putting it squarely in a rare category of intermediate-mass black holes, researchers report July 10 in Nature. More

Keep your eyes on the night sky this summer, scanning for the constellation Corona Borealis, and if you are lucky, you may glimpse what appears to be a new star winking on in the dark.

The brightening point of light will not be a new star, but a nova eruption about 3,000 light-years from Earth. There, a white dwarf star orbiting a red giant tears material from its larger companion. When enough mass collects on the white dwarf’s surface, the rising pressure and temperature will trigger a blast that can be seen from Earth with the naked eye — but for only a few days to a week. More