Featured Research

from universities, journals, and other organizations

Discovery of structure of radio source from a pulsar orbiting a massive star

Date:
May 2, 2011
Source:
Universidad de Barcelona
Summary:
For the first time the morphology of an extended radio source in a binary system formed of a pulsar and a massive star has been determined. In a few such systems, the strong interactions of the stellar winds produces high-energy gamma radiation, up to 10 million times more energetic than visible light. The results show for the first time the effect of the winds colliding and support existing theoretical models of radiation emitted by this type of high-energy binary systems, known as gamma-ray binaries.

Images taken 1 and 21 days after the periastron passage of PSR B1259-63 around the massive star LS 2883 with the Long Baseline Array (LBA) radio interferometer. The changing colour represents the intensity of the radiation detected. The small green ellipse is the projection of the orbit of the binary system and the black line shows a model of the trajectory of the nebular flow of particles that emit the synchrotron radiation.
Credit: Image courtesy of Universidad de Barcelona

In work led by researchers from the University of Barcelona, for the first time the morphology of an extended radio source in a binary system formed of a pulsar and a massive star has been determined. In a few such systems, the strong interactions of the stellar winds produces high-energy gamma radiation, up to 10 million times more energetic than visible light. The results, published in Astrophysical Journal Letters, show for the first time the effect of the winds colliding and support existing theoretical models of radiation emitted by this type of high-energy binary systems, known as gamma-ray binaries.

Related Articles


The research was carried out by Javier Moldón, Marc Ribó and Josep Maria Paredes, of the Department of Astronomy and Meteorology at the University of Barcelona and the UB Institute of Cosmos Sciences, together with Simon Johnston, of the Australia Telescope National Facility (Australia) and Adam Deller, of the National Radio Astronomy Observatory (USA), and in it they studied the only gamma-ray binary that is known to be formed of a pulsar (PSR B1259-63; that is, a neutron star with a radius of some 10 km that is spinning extremely fast) and a massive star (LS 2883), which is 30 times the mass of the Sun.

As the researchers from the UB explain, it is the first time that anyone has been able to observe the morphology, at different positions in the orbit, of the radio source of a gamma-ray binary in which the pulsar has known properties. The results show how the emission forms a type of cometary tail which moves around as the pulsar traces out its orbit. They have thus been able to see that the radio source is up to ten times larger than the orbit of the binary system.

The radio emission is produced during the periastron passage of the system -- which is the point at which the two components of the binary system are at their closet to each other -- once every 3.4 years. It has been shown that the radio emission is due to the synchrotron radiation produced by electrons that escape from the binary system at relativistic speeds of up to 100,000 km per second. This has allowed limits to be placed on the magnetization, which is essential for understanding the relativistic winds emitted by pulsars.

The PSR B1259-63/LS 2883 system is 7,500 light years away, in the direction of the constellation of Centaurus. The pulsar's orbit is 14 times larger than Earth's orbit around the Sun, but because of its extreme eccentricity, the pulsar passes within just 0.9 AU (astronomical units: Earth-Sun distance) during periastron. At such short distances the powerful wind from the massive star, travelling at over 1,000 km per second, collides with the wind from the pulsar, which is less dense but which travels at 100,000 km per second. This shock of winds accelerates particles that emit photons throughout the whole electromagnetic spectrum through synchrotron emission and inverse Compton scattering. The new radio observations directly show the radiation in the tail of particles accelerated in the shock, which spreads out over some 120 UA. This has allowed the researchers to infer the conditions under which the acceleration of the particles in produced in the region of the shock.

The observations of the binary system PSR B1259-63/LS 2883 were performed using the Australian Long Baseline Array (LBA) made up of five antennas separated by distances of up to 1,500 km. Using interferometry techniques, this network allowed the researchers to explore spatial scales of the order of 0.02 seconds of arc, an unprecedented resolution for observations of this binary system. To give an idea of the resolution involved, it corresponds to distinguishing features just 40 metres long on the surface of the Moon observed from Earth.


Story Source:

The above story is based on materials provided by Universidad de Barcelona. Note: Materials may be edited for content and length.


Journal Reference:

  1. Javier Moldón, Simon Johnston, Marc Ribó, Josep M. Paredes, Adam T. Deller. Discovery of extended and variable radio structure from the gamma-ray binary system PSR B1259-63/LS 2883. The Astrophysical Journal, 2011; 732 (1): L10 DOI: 10.1088/2041-8205/732/1/L10

Cite This Page:

Universidad de Barcelona. "Discovery of structure of radio source from a pulsar orbiting a massive star." ScienceDaily. ScienceDaily, 2 May 2011. <www.sciencedaily.com/releases/2011/04/110429120134.htm>.
Universidad de Barcelona. (2011, May 2). Discovery of structure of radio source from a pulsar orbiting a massive star. ScienceDaily. Retrieved November 21, 2014 from www.sciencedaily.com/releases/2011/04/110429120134.htm
Universidad de Barcelona. "Discovery of structure of radio source from a pulsar orbiting a massive star." ScienceDaily. www.sciencedaily.com/releases/2011/04/110429120134.htm (accessed November 21, 2014).

Share This


More From ScienceDaily



More Space & Time News

Friday, November 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Crowdfunded Moon Mission Offers To Store Your Digital Memory

Crowdfunded Moon Mission Offers To Store Your Digital Memory

Newsy (Nov. 19, 2014) — Lunar Mission One is offering to send your digital memory (or even your DNA) to the moon to be stored for a billion years. Video provided by Newsy
Powered by NewsLook.com
Accidents Ignite Debate on US Commercial Space Travel

Accidents Ignite Debate on US Commercial Space Travel

AFP (Nov. 19, 2014) — Serious accidents with two US commercial spacecraft within a week of each-other in October have re-ignited the debate over the place of private corporations in the exploration of space. Duration: 02:08 Video provided by AFP
Powered by NewsLook.com
Lunar Mission One Could Send Your Hair to The Moon

Lunar Mission One Could Send Your Hair to The Moon

Buzz60 (Nov. 19, 2014) — A British-led venture called Lunar Mission One plans to send a module to the moon with keepsakes from Earth. Vanessa Freeman (@VanessaFreeTV) tells you how to get your photos and DNA onboard. Video provided by Buzz60
Powered by NewsLook.com
Why A Russian Object Is Being Called A 'Satellite Killer'

Why A Russian Object Is Being Called A 'Satellite Killer'

Newsy (Nov. 18, 2014) — An unidentified Russian spacecraft is getting some attention, with some saying it could be for research while others say it could be a weapon. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins