Astronomy:SWIFT J1756.9−2508
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Short description: Millisecond pulsar in the constellation Sagittarius
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 17h 56m 57.200s |
| Declination | −25° 06′ 26.28″ |
| Astrometry | |
| Distance | 8000 pc |
| Details | |
| Mass | 1.8±0.4 M☉ |
SWIFT J1756.9−2508 is a millisecond pulsar with a rotation frequency of 182 Hz (period of 5.5 ms). It was discovered in 2007 by the Swift Gamma-Ray Burst Explorer and found to have a companion with a mass between 0.0067 and 0.030 solar masses. It is thought that the companion is the remnant of a former companion star, now stripped down to a planetary-mass core. The pulsar is accreting mass from this companion, resulting in occasional violent outbursts from the accumulated material on the neutron star.
Planetary system
SWIFT J1756.9-2508's only known planet is notable for its orbital period of less than an hour, about 54 minutes and 43 seconds.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | 7.8 (± 1.3) MJ | — | 0.0379907 (± 5e-07) d | — | — | — |
References
- H. A. Krimm; C. B. Markwardt; C. J. Deloye; P. Romano et al. (October 2007). "Discovery of the accretion-powered millisecond pulsar SWIFT J1756.9-2508 with a low-mass companion". Astrophysical Journal Letters 668 (2): L147–L150. doi:10.1086/522959. Bibcode: 2007ApJ...668L.147K.
- H. A. Krimm; C. B. Markwardt; C. J. Deloye; P. Romano et al. (October 2009). "ERRATUM: Discovery of the accretion-powered millisecond pulsar SWIFT J1756.9-2508 with a low-mass companion". Astrophysical Journal Letters 703 (2): L183. doi:10.1088/0004-637X/703/2/L183. Bibcode: 2009ApJ...703L.183K.
External links
- Universe Today, Pulsar Has Almost Completely Devoured a Star
- SIMBAD, "SWIFT J1756.9-2508" (accessed 2010-11-06)
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