Feeds

Hefty black hole weighs in at 33 Suns

Record-breaking stellar-mass heavyweight

Intelligent flash storage arrays

Researchers have confirmed that a black hole lurking in the dwarf galaxy IC 10, and dubbed IC 10 X-1, weighs in at up to 33 Suns, double the previous record for a "single star" black hole held by M33 X-7 which tips the scales at 16 Suns.

IC 10 X-1, lying 1.8 million light years from Earth, was first spotted back in 2007 by the US's Harvard-Smithsonian Centre for Astrophysics in Cambridge, New Scientist reports. Researchers estimated its weight at between 24 and 33 times the weight of our own Sun, but the result was speculative.

The researchers calculated the weight "based on the apparent orbit of a nearby companion star" deduced from "repeating dips in the brightness of X-rays coming from the black hole's vicinity" as the orbiting companion passed in front of a disc of hot, X-ray spewing material being sucked into the black hole.

Although they had no concrete evidence to back their figures, astronomers Jeffrey Silverman and Alexei Filippenko from the University of California at Berkeley have used spectra taken by the 10 metre Keck I telescope in Hawaii to confirm the result at between 23 and 33 solar masses.

The leeway in the black hole's possible weight is because the mass of its companion is unknown, NS explains.

While black holes can be "supermassive" monsters weighing billions of Suns, there's a limit on the size of black holes formed from the death of a single star - dubbed "stellar-mass" objects - depending on the star's mass and chemical make-up.

All stars lose material into space over their lifetimes, an amount determined by their chemical composition, and even the biggest bodies at up to 100 solar masses "can barely produce a 16-solar-mass black hole if they are born with a composition similar to the Sun's".

A more heavyweight prospect comes from stars "low in elements heavier than hydrogen and helium", according to astrophysicist Stanford Woosley of the University of California in Santa Cruz. These "cast off material less efficiently and could therefore have up to 42 solar masses available to form a black hole when they die".

Significantly, galaxy IC 10 "contains very few 'heavy' elements", NS notes.

IC 10 X-1 offers a possible explanation for "puzzlingly bright" X-ray sources spotted in other galaxies, so-called "ultra-luminous" sources which are 10 to 100 times brighter in X-rays than your average stellar-mass black holes. Some have suggested these are "intermediate mass black holes" weighing "hundreds or thousands of times" the mass of the Sun, which emit X-rays as they ingest matter.

However, Roy Kilgard of Wesleyan University in Middletown, Connecticut, reckons large stellar-mass black holes like IC 10 X-1, "undergoing especially bright outbursts of X-rays", could be the cause.

Kilgard suggests that there may be "many other stellar-mass black holes in this mass range that have eluded detection until now because they are farther away and harder to study", and concludes: "I expect in the coming years we'll identify many more of these things." ®

Note for commentators

Regarding the weight of IC 10 X-1 in Reg standard units, the Sun is reckoned to tip the scales at 1.9891 × 1030 kg. A Jub is, of course, 4.2kg.

We'll leave you to do the rest, and suggest the answer is probably best expressed in megaJubs.

Providing a secure and efficient Helpdesk

More from The Register

next story
SECRET U.S. 'SPACE WARPLANE' set to return from SPY MISSION
Robot minishuttle X-37B returns after almost 2 years in orbit
LOHAN crash lands on CNN
Overflies Die Welt en route to lively US news vid
You can crunch it all you like, but the answer is NOT always in the data
Hear that, 'data journalists'? Our analytics prof holds forth
Experts brand LOHAN's squeaky-clean box
Phytosanitary treatment renders Vulture 2 crate fit for export
No sail: NASA spikes Sunjammer
'Solar sail' demonstrator project binned
Carry On Cosmonaut: Willful Child is a poor taste Star Trek parody
Cringeworthy, crude and crass jokes abound in Steven Erikson’s sci-fi debut
Origins of SEXUAL INTERCOURSE fished out of SCOTTISH LAKE
Fossil find proves it first happened 385 million years ago
Human spacecraft dodge COMET CHUNKS pelting off Mars
Odyssey orbiter yet to report, though - comet's trailing trash poses new threat
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.