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http://hdl.handle.net/2248/5835
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DC Field | Value | Language |
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dc.contributor.author | Wade, G. A | - |
dc.contributor.author | Maiz, J. A | - |
dc.contributor.author | Martins, F | - |
dc.contributor.author | Petit, V | - |
dc.contributor.author | Grunhut, J | - |
dc.contributor.author | Walborn, N. R | - |
dc.contributor.author | Barba, R. H | - |
dc.contributor.author | Gagne, M | - |
dc.contributor.author | Garcia-Melendo, E | - |
dc.contributor.author | Jose, J | - |
dc.contributor.author | Moffat, A. F. J | - |
dc.contributor.author | Naze, Y | - |
dc.contributor.author | Neiner, C | - |
dc.contributor.author | Pellerin, A | - |
dc.contributor.author | Penades, O. M | - |
dc.contributor.author | Shultz, M | - |
dc.contributor.author | Simon-Diaz, S | - |
dc.contributor.author | Sota, A | - |
dc.date.accessioned | 2012-08-09T14:31:32Z | - |
dc.date.available | 2012-08-09T14:31:32Z | - |
dc.date.issued | 2012-09 | - |
dc.identifier.citation | Monthly Notices of the Royal Astronomical Society, Vol. 425, No. 2, pp. 1278–1293 | en |
dc.identifier.issn | 0035-8711 | - |
dc.identifier.uri | http://hdl.handle.net/2248/5835 | - |
dc.description | Restricted Access | en |
dc.description.abstract | This paper presents a first observational investigation of the faint Of?p star NGC 1624-2, yielding important new constraints on its spectral and physical characteristics, rotation, magnetic field strength, X-ray emission and magnetospheric properties. Modelling the spectrum and spectral energy distribution, we conclude that NGC 1624-2 is a main-sequence star of mass M ≃ 30 M⊙, and infer an effective temperature of 35 ± 2 kK and log g = 4.0 ± 0.2. Based on an extensive time series of optical spectral observations we report significant variability of a large number of spectral lines, and infer a unique period of 157.99 ± 0.94 d which we interpret as the rotational period of the star. We report the detection of a very strong (5.35 ± 0.5 kG) longitudinal magnetic field 〈B/subz/〉, coupled with probable Zeeman splitting of the Stokes I profiles of metal lines confirming a surface field modulus 〈B〉 of 14 ± 1 kG, consistent with a surface dipole of polar strength ≳20 kG. This is the largest magnetic field ever detected in an O-type star, and the first report of Zeeman splitting of Stokes I profiles in such an object. We also report the detection of reversed Stokes V profiles associated with weak, high-excitation emission lines of O iii, which we propose may form in the close magnetosphere of the star. We analyse archival Chandra ACIS-I X-ray data, inferring a very hard spectrum with an X-ray efficiency of log L/sub x/ /Lbol = −6.4, a factor of 4 larger than the canonical value for O-type stars and comparable to that of the young magnetic O-type star θ/sup1/ Ori C and other Of?p stars. Finally, we examine the probable magnetospheric properties of the star, reporting in particular very strong magnetic confinement of the stellar wind, with η/sub*/ ≃ 1.5 × 10/sup4/, and a very large Alfvén radius, R/subAlf/ = 11.4 R/sub*/ | en |
dc.language.iso | en | en |
dc.publisher | Wiley-Blackwell | en |
dc.relation.uri | http://dx.doi.org/10.1111/j.1365-2966.2012.21523.x | en |
dc.rights | © Royal Astronomical Society | en |
dc.subject | Binaries: spectroscopic | en |
dc.subject | Stars: early-type | en |
dc.subject | Stars: magnetic fields | en |
dc.subject | Stars: individual: NGC 1624-2 | en |
dc.title | NGC 1624-2: a slowly rotating, X-ray luminous Of?cp star with an extraordinarily strong magnetic field | en |
dc.type | Article | en |
Appears in Collections: | IIAP Publications Publications based on data from IAO, Hanle |
Files in This Item:
File | Description | Size | Format | |
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NGC 1624-2: a slowly rotating.pdf Restricted Access | Restricted Access | 1.11 MB | Adobe PDF | View/Open Request a copy |
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