Poster from the NASA Exoplanets Exploration Program’s Exoplanet Travel Bureau [credit: NASA/JPL-CalTech]
Before we start – ‘Pulsar planets are planets that are found orbiting pulsars, or rapidly rotating neutron stars.’
Wikipedia tells us:
‘PSR B1257+12, previously designated PSR 1257+12, […] is a pulsar located 2,300 light-years from the Sun in the constellation of Virgo. It is also named Lich, after a powerful, fictional undead creature of the same name.
The pulsar has a planetary system with three known planets, named “Draugr” (PSR B1257+12 b or PSR B1257+12 A), “Poltergeist” (PSR B1257+12 c, or PSR B1257+12 B) and “Phobetor” (PSR B1257+12 d, or PSR B1257+12 C), respectively.
They were both the first extrasolar planets and the first pulsar planets to be discovered; B and C in 1992 and A in 1994.
A is the lowest-mass planet yet discovered by any observational technique, with somewhat less than twice the mass of Earth’s moon.’
Under the heading ‘Planets’ it says:
‘In 1992, Wolszczan and Frail discovered that the pulsar had two planets. These were the first discovery of extrasolar planets to be confirmed; as pulsar planets, they surprised many astronomers who expected to find planets only around main-sequence stars. […] In 1994, an additional planet was discovered. Additionally, this system may have an asteroid belt or a Kuiper belt.’
So that’s some background, now the numbers which turn out to be straightforward enough, starting with the orbits:
727 A = 18365.474 days
276 B = 18365.564 days
187 C = 18365.531 days
The synodic results are:
727 – 276 = 451 A-B
276 – 187 = 89 B-C
727 – 187 = 540 A-C
So the ratios of 89:451:540 are almost exactly 1:5:6 (which equates to 90:450:540).
The only deviation, so to speak, from 1:5:6 is that B has 276 orbits in the period (just over 50 Earth years) rather than 277 – a very small difference.
via Tallbloke’s Talkshop
November 26, 2019 at 01:58PM
Iowa Climate Science Education 