Gamma ray double star

Gamma double star (engl. Gamma ray binary ) is the name given to a class of binary stars , the gamma rays with energies above 200 kilo electron volt emit. The highest energies proven to date reach a few hundred gigaelectron volts. The binary stars consist of a compact star , a neutron star or black hole in interaction with a massive star.

properties

In the case of gamma- ray binary stars , no accretion disk can be detected, as often occurs around the related X-ray binary stars . The spectral and photometric properties of the systems are periodic with the duration of the orbit . The path can be very eccentric . All gamma-ray binary stars also emit non-thermal synchrotron radiation in the range of radio radiation . With the help of Very Long Baseline Interferometry , extensive bipolar structures are always shown in the radio range.

Mechanisms for the creation of gamma rays in binary stars

The gravitational potential of neutron stars and black holes is sufficient for X-ray binary stars , but not for generating gamma radiation. The following mechanisms are assumed to be responsible for generating gamma rays:

• Inverse Compton scattering of UV radiation with charged particles in pulsar winds or relativistic jets from microquasars
• Interaction of pulsar winds with ions from the disk around Be stars
• Interaction of pulsar winds with the stellar winds of massive stars with masses greater than 15 solar masses

These binary stars are all known as X-ray binary stars in the X-ray field. Are outside the gamma-ray binary stars symbiotic novae as V407 Cygni. Here, gamma radiation is only produced briefly for a few days when the ejected matter of the nova hits the stellar wind of the accompanying red giant and pions are formed during the interaction and immediately decay again. The luminous blue variable Eta Carinae is also not counted among the gamma-ray double stars . It is true that this is also a binary star system that emits gamma radiation due to wind interaction in which stellar winds from two sources interact with one another. However, since it is an O star as a companion of the luminous blue variable and not a compact star, Eta Carinae is only referred to as a relative of the gamma-ray binary stars.

Examples

Due to the low resolution in gamma astronomy , gamma ray binary stars can usually only be identified if a periodic signal that has already been discovered in other wavelengths could be detected in the gamma radiation. The well-known gamma-ray binary stars include:

• Cygnus X-3
• PSR B1259-63
• LS 5039
• LSI + 61 ° 303
• HESS J0632 + 057

Individual evidence

1. ^ IF Mirabel: Revealing Gamma-Ray Binaries . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1201.3317v1 .
2. ↑ Javier Moldón, Marc Ribó, Josep M. Paredes: Periodic radio morphology of gamma-ray binaries . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1306.2830v1 .
3. ↑ M. Ackermann et al .: Periodic emission from the gamma-ray binary 1FGL J1018.6-5856 . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1201.3164v1 .
4. ^ Margarita Hernanz, Vincent Tatischeff: High energy emission of symbiotic recurrent novae: RS Ophiuchi and V407 Cygni . In: Astrophysics. Solar and Stellar Astrophysics . 2011, arxiv : 1111.4129v1 .
5. ↑ HESS Collaboration et al .: HESS observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1204.5690v1 .
6. ^ GE Romero, AT Okazaki, M. Orellana, SP Owocki: Accretion vs colliding wind models for the gamma-ray binary LS I +61 303: an assessment . In: Astrophysics. Solar and Stellar Astrophysics . 2007, arxiv : 0706.1320v2 .
7. ↑ Guillaume Dubus: Gamma-ray binaries: pulsars in disguise? In: Astrophysics. Solar and Stellar Astrophysics . 2006, arxiv : astro-ph / 0605287v1 .