X Per

From Remeis-Wiki
Jump to navigation Jump to search


Other Names: V* X Per Simbad, 4U 0352+309

Monitoring data: RXTE/ASM Swift/BAT MAXI

Coordinates

RA 03h 55' 23.077", DEC +31° 02' 45.01"
RA 58.8461542deg, DEC -31.0458361deg
l 163.0814, b -17.1362

Binary system

Distance: 0.95(20) kpc ([1])

Orbit

Parameter Value Unit Reference
Porb 250 days [2]
tau MJD
a sin i 2 AU [2]
e 0.11 [2]
omega deg

Description

4U 0352+309 is a persistent X-ray source in a binary with the Be-type star X Persei. It is believed that the neutron strar accretes material from the wind of either the Be companion atmosphere (fast, low-density) or its outskirts, i.e. the Be-disk (low, dense). A good summary and discussion about the different scenarios can be found in [3].

Spectrum

The spectrum of 4U 0352+309 is unusually hard and is detectable up to 200 keV in ISGRI. Earlier models describe the spectrum by a combination of two powerlaws ([4]) or a black body with an additional hard powerlaw ([5]). The later also requires an absorption like feature around 30 keV, which was interpreted as CRSF. A recent analysis by [3] showed, however, that the unusual spectrum can be described well by two thermal Comptonization models. Thereby the claimed cyclotron line is no longer needed. In addition, the used model, the relatively long pulse period of 837 s and by comparing to 4U 2206+54 may suggest the neutron star to have a magnetic field in the order of 1014 G, thus in the magnetar range.

References

  1. Cite error: Invalid <ref> tag; no text was provided for refs named Telting98
  2. 2.0 2.1 2.2 Cite error: Invalid <ref> tag; no text was provided for refs named DelgadoMarti2001
  3. 3.0 3.1 Cite error: Invalid <ref> tag; no text was provided for refs named Doroshenko2012
  4. Cite error: Invalid <ref> tag; no text was provided for refs named DiSalvo98
  5. Cite error: Invalid <ref> tag; no text was provided for refs named Coburn01