dc.contributor.author | Rosen, S.R. | |
dc.contributor.author | Prinja, R.K. | |
dc.contributor.author | Drew, J.E. | |
dc.contributor.author | Mason, K.O. | |
dc.contributor.author | Howell, S.B. | |
dc.date.accessioned | 2009-04-24T14:28:08Z | |
dc.date.available | 2009-04-24T14:28:08Z | |
dc.date.issued | 1998 | |
dc.identifier.citation | Rosen , S R , Prinja , R K , Drew , J E , Mason , K O & Howell , S B 1998 , ' Phase-resolved Hubble Space Telescope ultraviolet spectroscopy of V795 Her ' , Monthly Notices of the Royal Astronomical Society , vol. 299 , no. 2 , pp. 305-318 . https://doi.org/10.1046/j.1365-8711.1998.01844.x | |
dc.identifier.issn | 0035-8711 | |
dc.identifier.other | dspace: 2299/3297 | |
dc.identifier.uri | http://hdl.handle.net/2299/3297 | |
dc.description | ‘The definitive version is available at www.blackwell-synergy.com.’ Copyright Blackwell Publishing. DOI: 10.1046/j.1365-8711.1998.01844.x [Full text of this article is not available in the UHRA] | |
dc.description.abstract | We present highly time-resolved HST FOS UV spectroscopy of the nova-like binary V795 Her. Several key results emerge. For the first time we find a strong 2.6-h signature in the variability of the UV lines. The HST data reveal no evidence of a 4.8-h ‘period’, in contrast to our previous IUE observations. This, and differences in the spectral line characteristics, suggests that HST found the system in a different state from earlier IUE observations. The C IV line alone contains a fairly stable, asymmetric, extended blueward absorption trough which we associate with a wind outflow. The 2.6-h variations of the line profiles are largely confined to an interval of about 0.4 in phase and to the velocity regime −1500 < v < 0 km s−1, the changes being dominated by the apparent decline and re-emergence of a blueshifted emission peak. The complex profiles permit many empirical interpretations, but the simplest attributes the variability to a narrow (FWHM∼1000 km s−1) emission component which is always blueshifted with a mean velocity of around –600 km s−1. This interpretation, however, is not readily related to any obvious source within the binary. An alternative picture, which attempts to relate the UV and (simultaneously observed) optical line behaviour, invokes a more stable, broad (FWHM∼2000 km s−1) emission feature, the intrinsic morphology of which is disguised by superposed constant and variable absorption components. One tentative physical explanation of such a decomposition involves an accretion stream that overflows the accretion disc. However, several problems with this model remain to be resolved. We also draw attention to similarities between the velocity-restricted behaviour in the UV lines of V795 Her and that in the optical lines of T Tauri stars. This might indicate a connection between V795 Her and the magnetically influenced inflow/outflow characteristics associated with the central star in T Tauri systems. If such a connection were eventually demonstrated, it would reopen the question of whether the 2.6-h period in V795 Her is really the binary period and whether the system is in fact related to the intermediate polars. | en |
dc.language.iso | eng | |
dc.relation.ispartof | Monthly Notices of the Royal Astronomical Society | |
dc.subject | accretion discs | |
dc.subject | binaries | |
dc.subject | cataclysmic variables | |
dc.title | Phase-resolved Hubble Space Telescope ultraviolet spectroscopy of V795 Her | en |
dc.contributor.institution | School of Physics, Astronomy and Mathematics | |
dc.description.status | Peer reviewed | |
rioxxterms.versionofrecord | 10.1046/j.1365-8711.1998.01844.x | |
rioxxterms.type | Journal Article/Review | |
herts.preservation.rarelyaccessed | true | |