View source for GX 304-1

[[Category:Accreting X-ray Pulsars]]

'''Other names''' : 4U 1258-61 ([http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=gx+304-1&submit=SIMBAD+search SIMBAD])

'''Monitoring data''':
[http://heasarc.gsfc.nasa.gov/docs/swift/results/transients/weak/GX304-1// Swift/BAT]
[http://maxi.riken.jp/top/index.php?cid=000000000001&jname=J1301-616 MAXI]
[http://gammaray.nsstc.nasa.gov/gbm/science/pulsars/lightcurves/gx304m1.html Fermi/GBM pulsed flux]
[http://gammaray.nsstc.nasa.gov/gbm/science/occultation/lightcurves/GX304-1_multichan_fluxhist.png Fermi/GBM occultation]

'''Historical''': [http://xte.mit.edu/asmlc/srcs/gx304-1.html RXTE/ASM]

= Coordinates = 

RA 13h 01‘ 17.10“ DEC -61° 36‘ 13.16“

= Binary system =

Distance: 2.4±05 kpc (<ref name="Parkes80" />) 

== Orbit ==

Early determination by <ref name="Priedhorsky83" />: P<sub>orb</sub> = 132.5d 
with other parameters unknown.

The MAXI team redetermined the period from X-ray activity as P<sub>orb</sub> = 132.2d ([http://maxi.riken.jp/news/en/?p=1042 MAXI News])

<ref name="Sugizaki15" /> have determined the orbital ephemeris in detail, but with two separate solutions, depending on the assumed connection between spin changes and luminosity.
Both solutions use as orbital period P<sub>orb</sub> = 132.189 ± 0.02d and find the eccentricity around 0.5.

== Pulsations ==

Pulse period: 275.5s

== X-ray Spectrum ==

=== Cyclotron Features ===

* Cyclotron line at ~54 keV (<ref name="Yamamoto11" />, <ref name="Klochkov12" />)

== Optical Companion ==

''' Type ''': B2 Vne star (<ref name="Mason78" />)

{| class="wikitable"
!Parameter
!Value
!Unit
!Reference
|-
|B
|15.6
|
| [http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=gx+304-1&submit=SIMBAD+search SIMBAD]
|-
|V
| 13.40
|
| [http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=gx+304-1&submit=SIMBAD+search SIMBAD]
|}


'''References'''