WASHINGTON: Unlike the lonely sun, about half the stars in our Milky Way galaxy are in a long-term committed relationship with another star, orbiting each another in a celestial marriage called a binary system.
Researchers this week described one of these marriages gone wrong - a twosome that borders on the extreme, with the pair whirling around each other every 51 minutes in the fastest such orbital period known for a rare class of binary stars. As part of the drama, one star is eating its companion.
The two stars are located about 3,000 light years from Earth in the direction of the constellation Hercules. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).
The system belongs to a class of binary stars known as "cataclysmic variables" in which a star similar to our sun orbits close to what is called a white dwarf, basically a hot and compact core of a burned-out star. Variable just means that their combined brightness varies over time when viewed from Earth. Cataclysmic refers to the fact that this luminosity changes dramatically - by a factor of 10,000 or more in some cases.
Over millions of years, the distance between these two stars has narrowed to the point that they now are closer together than the moon is to Earth.
"Imagine if the moon zipped across the sky 10 times a night. That's the kind of speed we are talking about," said Massachusetts Institute of Technology astrophysicist Kevin Burdge, lead author of the study published this week in the journal Nature.
Being close does not mean they are being nice to each other, though - the white dwarf is mercilessly siphoning material from its partner.
This larger star is about the same temperature as the sun but has been stripped down to just about 10% of the sun's diameter - leaving it about the size of Jupiter, our solar system's largest planet. The white dwarf has a mass about 56% that of our sun but is densely packed, with a diameter about 1.5 times Earth's.
"It's an old pair of stars, where one of the two moved on - when stars die of old age they become white dwarfs - but then this remnant began to eat its companion," Burdge said.
"Basically, they were bound together for 8 billion years in a binary orbit. And now, right before the second one could end its stellar life cycle and become a white dwarf in the way that stars normally do - by evolving into a type of star called a red giant - the leftover white dwarf remnant of the first star interrupted the end of the companion's lifecycle and started slowly consuming it," Burdge said..
The researchers used data from the Palomar Observatory in California and telescopes in Hawaii and the Canary Islands.
Most stars are composed primarily of hydrogen, with lesser amounts of helium and other elements. The larger of the two stars in this binary - already growing old - is unusually helium-rich, not only because its companion has snacked on hydrogen from its outer layers but because it has lots of this element in its core through the slow process of fusing hydrogen atoms into helium in its thermonuclear caldron.
This binary system periodically brightens and fades in part because the larger star is being physically deformed into a teardrop shape, rather than spherical, by the white dwarf's gravitational tug.
There are more than a thousand known cataclysmic variables, though only a dozen have orbital periods below 75 minutes. While this binary system's 51 minutes is speedy, it is not a record when compared to other classes of binaries. The fastest-known orbital period among binaries is just 5 minutes and 21 seconds, with two white dwarfs orbiting one another.
"There is tons of wild stuff going on in space," Burdge said.
Reuters
Sun Oct 09 2022
An artist's illustration shows a white dwarf and larger, sun-like star forming a "cataclysmic" binary system, seen in this undated handout image. - via REUTERS
Astro AWANI's revamped English news website, AWANI International, launches on Oct 21
Astro AWANI's revamped English platform delivers in-depth global news and expert analysis to keep you informed on key developments.
Israeli strikes kill 33 people in Jabalia refugee camp in Gaza, medics say
Residents of Jabalia said Israeli tanks had reached the heart of the camp after pushing through suburbs and residential districts.
Liam Payne's ex-partner calls for media restraint after 'painful' death
Cheryl Tweedy used her statement to urge the media to remember they had a seven-year-old son, Bear, who could read the reports.
Analysts: Indonesia's strong MoF leadership team to boost investor confidence
Sri Mulyani Indrawati as head of Indonesia's Ministry of Finance is expected to instil confidence among investors.
Biden offers both a carrot and a stick to Israel as his term nears an end
Israel has frequently resisted US advice and has caused political difficulties for the Biden administration.
Putin says BRICS will generate most of global economic growth
Russian President Vladimir Putin will host a summit of the group in the city of Kazan on Oct. 22-24.
ISIS Malaysia's perspective of Budget 2025
An excellent rakyat-centric budget under the overarching principle of a caring and humane economy.
Budget 2025: Record increase in STR, SARA aid initiatives
The government will provide a significant boost to the Sumbangan Tunai Rahmah (STR) and Sumbangan Asas Rahmah (SARA) initiatives next year.
Budget 2025: EPF contributions to be made mandatory for foreign workers – PM Anwar
The government plans to make it compulsory for all non-citizen workers to contribute to the Employees Provident Fund (EPF).
What policies to expect from Indonesia's new President Prabowo
Prabowo will be open to foreign investment, his aide has said, such as by offering investors management of airports and sea ports.
Budget 2025: Govt allocates RM470 mil to empower women's participation in PMKS
The Women's Leadership Apprenticeship Program will be intensified as an effort to produce more female corporate personalities.
Israel sends more troops into north Gaza, deepens raid
Residents of Jabalia in northern Gaza said Israeli tanks had reached the heart of the camp, using heavy air and ground fire.
Indonesia ramps up security ahead of Prabowo's inauguration
Prabowo Subianto will be sworn in as Indonesia's president on Sunday with Vice President-elect, Gibran Rakabuming Raka, also taking office.
Immediate allocation of RM150 mil for local authorities, DID to tackle flash floods
Datuk Seri Anwar Ibrahim said this allocation is intended to address the recent flash floods that hit the capital and several major towns.
Budget 2025: Sabah, Sarawak to continue receiving among highest allocations - PM
Sabah and Sarawak continues to be prioritised under Budget 2025, with allocations of RM6.7 billion and RM5.9 billion respectively.
NFOF will be operational in November 2024 with funding of RM1 bil
PM Anwar Ibrahim said NFOF will support venture capital fund managers to invest in startup companies with RM300 million set aside for 2025.
Minimum wage to increase to RM1,700 effective Feb 1, 2025
The Progressive Wage Policy would be fully enforced next year with an allocation of RM200 million, benefiting 50,000 workers.
Bursa Malaysia ends higher on Budget 2025 optimism
The benchmark index, which opened 1.85 points higher at 1,643.29, moved between 1,641.71 and 1,649.31 throughout the trading session.
Five important aspects relating to people’s lives in Budget 2025 - PM
The focus is on driving the MADANI Economy, speeding reforms, cutting red tape, raising wages, and tackling the cost of living.
Economic outlook: Govt plans to leverage, expand existing city transit system
The expansion aims to provide a more efficient and reliable public transportation network, reduce congestion, and improve accessibility.