double star
double star — noun
1. a pair of stars that look close to each other when seen from Earth.
a pair of stars that look close to each other when seen from Earth.
Amara's telescope revealed a double star near Orion — two bright points almost touching.
collocation: double star + near [constellation]
Through his small telescope, Dimitri could see the double star as a pair of suns.
The astronomy club spent the evening spotting double stars — two suns that sat very close.
Keiko sketched the double star's two bright specks side by side in her notebook.
Our guide showed us a bright double star that the eyepiece split into two.
- visual double
emphasises the observational aspect rather than any physical relationship
用法筆記
This is the broadest meaning of double star. It describes how they look from Earth and does not say whether the two stars are physically linked or just happen to line up.
常見錯誤
2. two stars that happen to lie along the same direction from Earth but have no phy
two stars that happen to lie along the same direction from Earth but have no physical connection — one star is simply much farther behind the other in space, and they only look like a pair.
Fatima's textbook explained that some double stars are only chance alignments in the sky.
contrast: chance alignment vs physical pair
Sven's double star turned out to be two unrelated suns on the same sightline.
Beatriz learned her double star was just two distant stars that lined up.
Rafael's data showed the double star had no gravitational link at all.
Hana pointed out a double star that was actually a trick of perspective from Earth.
- optical double
the standard astronomical term for this specific type of double star
用法筆記
Distinguish from sense 3 (GRAVITY BOUND): the two stars in a chance alignment are not held together by gravity and belong to separate star systems. They only appear near each other from our viewpoint.
常見錯誤
3. two suns held together by the pull of gravity, circling around a shared centre o
two suns held together by the pull of gravity, circling around a shared centre of mass like partners in a slow dance — a real physical pair rather than just two stars that happen to line up.
Daichi noted the double star's two suns orbit each other once every eighty years.
collocation: orbit each other
Arun calculated the mass of both stars in the double star system.
Yara detected a wobble in the double star that suggested a hidden third body.
Imani watched the double star spin around its shared centre of gravity like a cosmic dance.
Mateo's team found that the double star would eventually merge into a single object.
- binary star
the standard astronomical term; emphasises the gravitational bond between the two stars
- physical double
stresses the real physical connection, used more often in older astronomy texts
用法筆記
Distinguish from sense 2 (CHANCE ALIGNMENT): these two stars are gravitationally bound and physically orbit each other. They form a true system, not a line-of-sight coincidence.