A Predicted 'New Star' Didn't Appear in the Night Sky. Astronomers Expect It Soon (space.com) 8
Space.com calls it "the once-in-a-lifetime reignition of a long-dead star in an explosion powerful enough to briefly match the brilliance of Polaris, the North Star." In March CNN promised this once-every-79-years event would happen "anytime between now and September."
But it didn't...
Space.com has a spectacular animation showing what this "recurring nova" was supposed to look like (described by CNN as a "sudden, brief explosion" from a collapsed/"white dwarf" star). "The highly-anticipated 'guest star' of the night sky has yet to deliver its grand performance," adds Space.com, "but we have an update." For a quick recap... T Coronae Borealis — often called T Cor Bor or T CrB — is home to a white dwarf, a dense, burnt-out star siphoning material from its companion star, which is a massive red giant close to the end of its life. This material spirals into an accretion disk around the white dwarf, where it slowly coats the star's surface. Every 80 years or so, the white dwarf manages to accumulate enough mass to trigger a nuclear explosion, sparking an outburst that boosts its typically dim magnitude of 10 to a bright 2.0 — that should look like a "new star" in the night sky to us...
[T]he elusive system continues to show signs that an outburst is still imminent. So, what gives? "We know it has to happen," astrophysicist Elizabeth Hays, who is watching T CrB every day using NASA's Fermi gamma-ray space telescope, told Space.com in a recent interview. "We just can't pin it down to the month."
The unpredictability stems partly from limited historical records of T CrB's outbursts. Only two such eruptions have been definitively observed in recent history: on May 12, 1866, when a star's outburst briefly outshined all the stars in its constellation, reaching magnitude 2.0, and again on February 9, 1946, when it peaked at magnitude 3.0. These events appear to follow the star's roughly 80-year cycle, suggesting that the next outburst may not occur until 2026. However, in February 2015, the system brightened in a manner reminiscent of its behavior in 1938, eight years before its 1946 eruption. This rise in brightness suggested T CrB's outburst was accelerated to 2023. The system also endured a "unique and mysterious" dimming about a year before its 1946 outburst, and a similar dip started in March last year, prompting astronomers to adjust their predictions to 2024.
Yet, the cause of this pre-eruption dip in brightness remains unclear, making it only a coincidental predictor. "We got really excited when it looked like it was doing similar things," said Hays. "Now we're learning, 'Oh, there's another piece we can't see.'" Moreover, the rate at which the red giant's material is being drawn toward the white dwarf may fluctuate over the years, making it trickier to put a date on the calendar for the outburst, Edward Sion, a professor of astronomy and astrophysics at Villanova University in Pennsylvania, told Space.com... "There's a lot of uncertainty about the actual average accretion rate," said Sion.
The article points out that last time there was an eruption, "there were no X-ray or gamma-ray telescopes in space, so there is no data from wavelengths other than optical to shed light on what happened before the outburst." But this time astrophysicist Hays says "We're getting the best dataset we've ever had on what does nova look like before it goes off".
Space.com says "this wealth of data will allow them to better predict future outbursts, and will eventually benefit models of how stars work."
Thanks to long-time Slashdot reader Okian Warrior for sharing the article.
But it didn't...
Space.com has a spectacular animation showing what this "recurring nova" was supposed to look like (described by CNN as a "sudden, brief explosion" from a collapsed/"white dwarf" star). "The highly-anticipated 'guest star' of the night sky has yet to deliver its grand performance," adds Space.com, "but we have an update." For a quick recap... T Coronae Borealis — often called T Cor Bor or T CrB — is home to a white dwarf, a dense, burnt-out star siphoning material from its companion star, which is a massive red giant close to the end of its life. This material spirals into an accretion disk around the white dwarf, where it slowly coats the star's surface. Every 80 years or so, the white dwarf manages to accumulate enough mass to trigger a nuclear explosion, sparking an outburst that boosts its typically dim magnitude of 10 to a bright 2.0 — that should look like a "new star" in the night sky to us...
[T]he elusive system continues to show signs that an outburst is still imminent. So, what gives? "We know it has to happen," astrophysicist Elizabeth Hays, who is watching T CrB every day using NASA's Fermi gamma-ray space telescope, told Space.com in a recent interview. "We just can't pin it down to the month."
The unpredictability stems partly from limited historical records of T CrB's outbursts. Only two such eruptions have been definitively observed in recent history: on May 12, 1866, when a star's outburst briefly outshined all the stars in its constellation, reaching magnitude 2.0, and again on February 9, 1946, when it peaked at magnitude 3.0. These events appear to follow the star's roughly 80-year cycle, suggesting that the next outburst may not occur until 2026. However, in February 2015, the system brightened in a manner reminiscent of its behavior in 1938, eight years before its 1946 eruption. This rise in brightness suggested T CrB's outburst was accelerated to 2023. The system also endured a "unique and mysterious" dimming about a year before its 1946 outburst, and a similar dip started in March last year, prompting astronomers to adjust their predictions to 2024.
Yet, the cause of this pre-eruption dip in brightness remains unclear, making it only a coincidental predictor. "We got really excited when it looked like it was doing similar things," said Hays. "Now we're learning, 'Oh, there's another piece we can't see.'" Moreover, the rate at which the red giant's material is being drawn toward the white dwarf may fluctuate over the years, making it trickier to put a date on the calendar for the outburst, Edward Sion, a professor of astronomy and astrophysics at Villanova University in Pennsylvania, told Space.com... "There's a lot of uncertainty about the actual average accretion rate," said Sion.
The article points out that last time there was an eruption, "there were no X-ray or gamma-ray telescopes in space, so there is no data from wavelengths other than optical to shed light on what happened before the outburst." But this time astrophysicist Hays says "We're getting the best dataset we've ever had on what does nova look like before it goes off".
Space.com says "this wealth of data will allow them to better predict future outbursts, and will eventually benefit models of how stars work."
Thanks to long-time Slashdot reader Okian Warrior for sharing the article.
Re: Mainstream science fails again (Score:1)
What if margins of error are wide enough in science to be politically exploitable, longer than you can stay solvent?
Re: (Score:2)
Of course, it will wait until it is near the sun (Score:2)
Did someone ... (Score:2)
Predicting the future is still hard. (Score:1)
Further bulletins as events warrant.