PSR B1620-26
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 The location of PSR B1620−26 (circled) |
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| Observation data Equinox J2000.0 |
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|---|---|
| Constellation | Scorpius (M4) |
| Right ascension | 16h 23m 38s |
| Declination | −26° 31′ 53″ |
| Apparent magnitude (V) | +24 |
| Characteristics | |
| Spectral type | Pulsar / DB |
| U-B color index | ? |
| B-V color index | ? |
| Variable type | none |
| Astrometry | |
| Radial velocity (Rv) | ? km/s |
| Proper motion (μ) | RA: ? mas/yr Dec.: ? mas/yr |
| Parallax (π) | ? ± ? mas |
| Distance | 12,400 ly (3,800 pc) |
| Absolute magnitude (MV) | ? |
| Details | |
| Mass | 1.35 / 0.34 M☉ |
| Radius | ? R☉ |
| Luminosity | ? L☉ |
| Temperature | ? K |
| Metallicity | ? |
| Rotation | ? |
| Age | ? / 13000 million years |
| Other designations | |
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PSR J1623−2631,
16:23:38.22−23:31:53.8 J2000, 16:23:38.24−26:31:53.9, ICRS 2000 |
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PSR B1620−26 is a binary star about 12,400 light-years away in the constellation Scorpius (M4).
It is theorized that originally PSR B1620−26 A had another, lower mass white dwarf companion, which was ejected when the current PSR B1620−26 B interacted with the original binary system. At that time, B1620−26 B was still a main sequence star, with its planet (PSR B1620−26c). Whereupon, the planet settled into orbit around both stars.
The triple system is just outside the core of the globular cluster. The age of the cluster has been estimated to be about 12.7 billion years. Hence this is the age estimate for the birth of the planet, and two stars.
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[edit] Planet system
PSR B1620−26c was originally detected through the Doppler shifts its orbit induces on signals from the star it orbits (in this case, changes in the apparent pulsation period of the pulsar).
In the early 1990s, a group of astronomers led by Donald Backer, studying what they thought was a binary pulsar, determined that a third object was needed to explain the observed Doppler shifts. Within a few years, the gravitational effects of the planet on the orbit of the pulsar and white dwarf had been measured, giving an estimate of the mass of the third object that was too small for it to be a star. The conclusion that the third object was a planet was announced by Stephen Thorsett and his collaborators in 1993.
| Companion (In order from star) |
Mass (MJ) |
Orbital period (days) |
Semimajor axis (AU) |
Eccentricity |
|---|---|---|---|---|
| c | 2.5 ± 1 | ~36,500 | 23 | low |
[edit] See also
[edit] References
- SolStation: PSR B1620-26
- Extrasolar Visions: PSR B1620-26 A + PSR B1620-26 B
- Z. Arzoumanian, K. Joshi, F. A. Rasio, S. E. Thorsett (1999). "Orbital Parameters of the PSR B1620-26 Triple System". Proceedings of the 160th colloquium of the International Astronomical Union 105: 525.
[edit] External links
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