1A 1118-616
Also known as: 2E 1118.7-6138 [SIMBAD]
Monitoring data: RXTE/ASM Swift/BAT Fermi/GBM pulsed flux
Coordinates
RA 11h 20m 57.215s, Dec -61° 55' 00.29"
RA 170.238 , Dec -61.916747
l 292.4986 , b -00.8918
Binary system
Distance is estimated to be 5±2 kpc [1].
Discovered during an outburst in 1974 by Ariel-5 [2]. Only 3 outburst observed: 1974 [2], 1992 [3] and 2009 [4] [5]
Orbit
| Parameter | Value | Unit | Reference |
|---|---|---|---|
| Porb | 24.0±0.4 | days | [6] |
| T π/2 | 54845.37±0.4 | MJD | [6] |
| a sin i | 54.85±1.4 | lt-sec | [6] |
| e | 0.0 | [6] |
Note: Due to the fact that the source was only observed for short periods throughout the outbursts, the orbital solutions were not constrained prior to [6]. The eccentricity was fixed to 0 in the orbit determination of the orbital solution [6].
Optical Companion
The optical counterpart was identified as the Be-star Hen 3−640/Wray 793 [7] and classified as an O9.5IV-Ve star with strong Balmer emission lines indicating an extended envelope [1]. [3] showed a strong correlation between the strength of the Hα emission line and the X-ray activity.
Pulsar
The pulse period was determined during the first outburst at 405.3¬±0.6s [8]. In the second outburst the pulse period was measured with ~406.5s and a change of of∼−0.016 s/day. [4] measured a pulse period of 407.719s with a change of ~0.04s/day during the outburst in 2009.
Available data
2009 Outburst
- RXTE: multiple observations throughout the outburst [4] [6]
- INTEGRAL: One observation a few weeks after the main peak
- Suzaku: 2 Observations: one in the peak, one after the outburst [5]
References
- ↑ 1.0 1.1 Janot-Pacheco, E., Ilovaisky, S.A., Chevalier, C., 1981, A&A, 99, 274 (NASA ADS)
- ↑ 2.0 2.1 Eyles, Skinner, Willmore, et al., 1975, Nature 254, 577 (NASA ADS)
- ↑ 3.0 3.1 Coe, M. J., Roche, P., Everall, C., et al., 1994, A&A 289, 784 (NASA ADS)
- ↑ 4.0 4.1 4.2 Doroshenko, V., Suchy, S., Santangelo, A., et al., 2010, A&A, 515, L1 (NASA ADS)
- ↑ 5.0 5.1 Suchy, S., Pottschmidt, K., Rothschild, R.E., et al., 2011, arXiv:1103.1370 (NASA ADS)
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Staubert, Pottschmidt, Doroshenko, et al., 2011, A&A 527, 7 (NASA ADS)
- ↑ Chevalier & Ilovaisky, 1975, IAU Circ. 2778 (NASA ADS)
- ↑ Ives, Sanford, & Bell Burnell, 1875, Nature 154, 578 (NASA ADS)