{"paper":{"title":"HST spectrum and timing of the ultra-compact X-ray binary candidate 47 Tuc X9","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.HE","authors_text":"A. Bahramian, C. Knigge, C. O. Heinke, C. T. Britt, D. M. Russell, D. R. Zurek, F. Bernardini, G. E. Anderson, G. R. Sivakoff, J. C. A. Miller-Jones, J. Strader, L. Chomiuk, M. D. Albrow, M. van den Berg, R. M. Plotkin, R. Soria, S. Bogdanov, T. J. Maccarone, T. M. Tauris, V. Tudor","submitted_at":"2018-02-01T05:36:27Z","abstract_excerpt":"To confirm the nature of the donor star in the ultra-compact X-ray binary candidate 47 Tuc X9, we obtained optical spectra (3,000$-$10,000 {\\AA}) with the Hubble Space Telescope / Space Telescope Imaging Spectrograph. We find no strong emission or absorption features in the spectrum of X9. In particular, we place $3\\sigma$ upper limits on the H$\\alpha$ and HeII $\\lambda 4686$ emission line equivalent widths $-$EW$_{\\mathrm{H\\alpha}} \\lesssim 14$ {\\AA} and $-$EW$_{\\mathrm{HeII}} \\lesssim 9$ {\\AA}, respectively. This is much lower than seen for typical X-ray binaries at a similar X-ray luminosit"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1802.00161","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}