The X-ray transient XTE J1719–291 was discovered with RXTE/PCA during its outburst in 2008 March , which lasted at least 46 days .
Its 2-10 keV peak luminosity is 7 \times 10 ^ { 35 } erg s ^ { -1 } assuming a distance of 8 kpc , which classifies the system as a very faint X-ray transient .
The outburst was monitored with Swift , RXTE , Chandra and XMM-Newton .
We analysed the X-ray spectral evolution during the outburst .
We fitted the overall data with a simple power-law model corrected for absorption and found that the spectrum softened with decreasing luminosity .
However , the XMM-Newton spectrum can not be fitted with a simple one-component model , but it can be fit with a thermal component ( black body or disc black body ) plus power-law model affected by absorption .
Therefore , the softening of the X-ray spectrum with decreasing X-ray luminosity might be due to a change in photon index or alternatively it might be due to a change in the properties of the soft component .
Assuming that the system is an X-ray binary , we estimated a long-term time-averaged mass accretion rate of \langle \dot { M } _ { \mathrm { long } } \rangle \sim 7.7 \times 10 ^ { -13 } ~ { } \mathrm { M } _ { \odot } yr ^ { -1 } for a neutron star as compact object and \langle \dot { M } _ { \mathrm { long } } \rangle \sim 3.7 \times 10 ^ { -13 } ~ { } \mathrm { M } _ { \odot } yr ^ { -1 } in the case of a black hole .
Although no conclusive evidence is available about the nature of the accretor , based on the X-ray/optical luminosity ratio we tentatively suggest that a neutron star is present in this system .