Equation 9 · Part 1 · A Neutron Star Is a Redshift Standard
Symbol z_s
What this part means
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Its job in the formula
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol z_s→Article meaning
The passage around this formula
— a function of the star’s compactness alone, so that whatever fraction of a percent of uncertainty NICER puts on M and R propagates directly into the redshift. The paper works through six NICER-mapped pulsars this way, and two of them mark the range worth remembering. PSR J0740+6620, the most massive precisely-timed neutron star known, comes in at roughly 2.07\, with a radio-timing mass fixed independently by Shapiro delay to 2.080.07\, [ 4 ] , giving a compactness near 0.25 and a surface redshift 0.40 — the deepest gravitational potential in the sample, though also, because its radius is the harder-measured half of the pair, the least precisely known redshift, at…
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Sources cited in the surrounding passage
- [4] Refined Mass and Geometric Measurements of the High-mass PSR J0740+6620 ↗
- [3] A NICER View of the Nearest and Brightest Millisecond Pulsar: PSR J0437-4715 ↗
These citations provide research context; check each source for the exact claim it supports.