For his size, Ol’Sanduleak was getting old, at a bit more than 20 million years. That would normally be young for a star, but Sanduleak was one of those hot blue B3 types.
His stellar nursery was crowded. In younger millennia, he was almost accredited several times by a couple of red giants. Saved at last, by a passing black hole that flung him out of that nursery.
Of course Sanduleak was a hungry sol himself, dining on suns of much greater age: yellow type Os; Brown Dwarfs; entire planetary systems.
He was beginning to feel weary when he happened across a solitary type M star. She was sweet, not so petite by any means, maybe tipping the scales at 5 or 6 solar mass. But compared to his 15, she was a banquet.
He thoroughly enjoyed the dance they did. Around and around, for thousands of years, slowly nudging closer together. A kiss of coronas, an exchange of photospheres, until by chance, their magnetic fields aligned just so, and she fell into his bulk in one big slurp.
Wow, what a scene. Sanduleak was so excited he ejected a pair of plasma rings and bathed the local group with renewed brilliance.
But her bustle was a basket of beryllium and metals, sans hydrogen and helium to help hold his blue hue. With inner layers cooling, his temperature profile suffered. Still millions of degrees mind you, making silicon, sulfur, and Carbon, but too cold to burn Iron.
After the climax of acquisition, lethargy settled in and he quickly approached exhaustion. For 20,000 years, Sanduleak struggled to burn blue, until his fusions fires faltered and gravity smote him.
In the blink of an eye, he vanished from the cosmos. He was still there, but the inrush from gravity’s collapse created a reverse shock that absorbed and hid everything inside him, even light.
His core pressure and temp rose to true particle smashing levels. Half his mass was liberated as neutrinos, which ‘could’ escape the shock. The other half was bottled up in his innards for hours.
In his billion degree gut, Iron ignited and burned to elements all the way past Uranium. When the shock reached his center it release all that energy, and exploded out of his belly with the power of an entire galaxy.
Sanduleak died 168,031 years ago. But, since we were not so far away from that little galaxy, we saw SN1987A announce itself when the ghost of his remnant neutrinos rushed past Earth not so long ago.