Binary pulsar
A binary pulsar is a
History
The binary pulsar
The study of the PSR B1913+16 binary pulsar also led to the first accurate determination of neutron star masses, using relativistic timing effects.[2] When the two bodies are in close proximity, the gravitational field is stronger, the passage of time is slowed – and the time between pulses (or ticks) is lengthened. Then as the pulsar clock travels more slowly through the weakest part of the field it regains time. A special relativistic effect, time dilation, acts around the orbit in a similar fashion. This relativistic time delay is the difference between what one would expect to see if the pulsar were moving at a constant distance and speed around its companion in a circular orbit, and what is actually observed.
Prior to the
The measurements made of the orbital decay of the PSR B1913+16 system were a near perfect match to Einstein's equations. Relativity predicts that over time a binary system's orbital energy will be converted to
Intermediate mass binary pulsar
An intermediate-mass binary pulsar (IMBP) is a pulsar-white dwarf binary system with a relatively long spin period of around 10–200 ms consisting of a white dwarf with a relatively high mass of approximately [7] The spin periods, magnetic field strengths, and orbital eccentricities of IMBPs are significantly larger than those of low mass binary pulsars (LMBPs).[7] As of 2014, there are fewer than 20 known IMBPs.[8] Examples of IMBPs include PSR J1802−2124[7] and PSR J2222−0137.[8]
The binary system PSR J2222−0137 has an orbital period of about 2.45 days and is found at a distance of 267+1.2
-0.9 pc (approximately 870 light-years), making it the second closest known binary pulsar systems (as of 2014) and one of the closest pulsars and neutron stars.[8] The relatively high-mass pulsar (1.831 0.010 ) has a companion star PSR J2222−0137 B with a minimum mass of approximately 1.3 solar masses (1.319 0.004 ).[9] This meant the companion is a massive white dwarf (only about 8% of white dwarfs have a mass ), which would make the system an IMBP. Although initial measurements gave a mass of about 1 solar mass for the PSR J2222−0137 B,[8] later observations showed that it is actually a high-mass white dwarf[9] and also one of the coolest known white dwarfs, with a temperature less than 3,000 K.[8]
PSR J2222−0137 B is likely crystallized, leading to this Earth-sized white dwarf being described as a "diamond-star",
Effects
Sometimes the relatively normal companion star of a binary pulsar will swell up to the point that it dumps its outer layers onto the pulsar. This interaction can heat the gas being exchanged between the bodies and produce X-ray light which can appear to pulsate, in a process called the X-ray binary stage. The flow of matter from one stellar body to another often leads to the creation of an accretion disk about the recipient star.
Pulsars also create a "wind" of relativistically outflowing particles, which in the case of binary pulsars can blow away the magnetosphere of their companions and have a dramatic effect on the pulse emission.
See also
- Astronomy – Scientific study of celestial objects
- PSR B1913+16– Pulsar in the constellation Aquila
- PSR J0737-3039– Double pulsar in the constellation Puppis
- Square Kilometre Array – Radio telescope under construction in Australia and South Africa
References
- ^ S2CID 118573183.
- ^ doi:10.1086/159690.
- S2CID 124959784.
- .
- ^ "Prof. Martha Haynes Astro 201 Binary Pulsar PSR 1913+16 Website".
- S2CID 120688730.
- ^ S2CID 119183244.
- ^ S2CID 19986066.
- ^ S2CID 236134389.
- ^ Drake, Nadia (24 June 2014). "Astronomers Find Slow-Cooked Diamond the Size of Earth". National Geographic. Archived from the original on March 21, 2021.
- ^ Fazekas, Andrew (26 August 2011). ""Diamond" Planet Found; May Be Stripped Star". National Geographic. Archived from the original on May 17, 2021.
External links
- Prof. Martha Haynes Astro 201 Binary Pulsar PSR 1913+16 Website
- Nobel Prize for the binary pulsar discovery
- Neutron Star Masses Archived 2012-10-17 at the Wayback Machine
- D. Lorimer (2008). "Binary and millisecond pulsars". Living Reviews in Relativity. 11 (1): 8. PMID 28179824.
- C. Will (2001). "The confrontation between general relativity and experiment". Living Reviews in Relativity. 4 (1): 4. PMID 28163632.
- I. H. Stairs (2009). "Binary pulsars and tests of general relativity". Proceedings of the International Astronomical Union. 5: 218–227. .