Using the ACS on HST, we have surveyed the F UV and NUV populations in the core region of M 80. The CMD reveals large numbers of blue and extreme horizontal branch stars and blue stragglers, as well as ≈ 60 objects lying in the region of the CMD where accreting and detached white dwarf binaries are expected. Overall, the blue straggler stars are the most centrally concentrated population, with their radial distribution suggesting a typical blue straggler mass of about 1.2 M ⊙ . However, counterintuitively, the faint blue stragglers are significantly more centrally concentrated than the bright ones and a Kolmogorov-Smirnov test suggest only a 3.5% probability that both faint and bright blue stragglers are drawn from the same distribution. This may suggest that (some) blue stragglers get a kick during their formation. We have also been able to identify the majority of the known X-ray sources in the core with F UV bright stars. One of these F UV sources is a likely dwarf nova that was in eruption at the time of the F UV observations. This object is located at a position consistent with Nova 1860 AD, or T Scorpii. Based on its position, X-ray and UV characteristics, this system is almost certainly the source of the nova explosion. The radial distribution of the X-ray sources and of the cataclysmic variable candidates in our sample suggest masses > 1M ⊙ .
We present the results of a multiwavelength (far‐ultraviolet to I band) survey of the stellar populations of the globular cluster NGC 6752, using Space Telescope Imaging Spectrograph (STIS), Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. We have confirmed that two previously identified cataclysmic variable (CV) candidates are, in fact, dwarf novae which underwent outbursts during our observations. We have also identified previously unknown optical counterparts to two X‐ray sources. We estimate the position of the centre of the cluster, and show that the stellar density profile is not well described by a single King model, indicating that this cluster is in a core‐collapsed or post‐core‐collapse phase. The colour–magnitude diagram shows a well‐populated horizontal branch, numerous blue stragglers and white dwarfs (WDs), as well as 87 sources in the gap region where we expect to find WD–main‐sequence binaries, including CVs. The X‐ray sources and WD binary systems are the most centrally concentrated populations, with dynamically estimated characteristic masses >1.1 and >0.8 M⊙, respectively.
We have searched for variable sources in the core region of M 80, using far‐ultraviolet (FUV) data taken with the Advanced Camera for Surveys on board the Hubble Space Telescope. We found three sources that exhibit strong signs of variability in our data. Among these is source TDK 1, which we believe to be an RR Lyrae star that reached maximum brightness during our observations. The light curve shows a ≳3 mag FUV brightening over the course of ≈5 h, with an estimated peak brightness of ≈16.7 mag, followed by a decrease to ≈20 mag. Archival optical data obtained with Wide‐Field Planetary Camera 2 confirm that TDK 1 is variable in all wavebands. TDK 1's spectral energy distribution is reasonably fitted by a star with temperature K and radius , consistent with the suggestion that it is an RR Lyrae. Based on the photometric and variability characteristics of the other two variables, we suggest that TDK 2 is likely to be an SX Phoenicis star with min period, and TDK 3 is likely another RR Lyrae. Finally, we briefly discuss the FUV counterparts to two previously known variables in M 80, the classical nova T Sco and the dwarf nova DN 1.
This paper aims to identify and examine motivational and environmental factors that impact entrepreneurial intentions of Emirati undergraduates in the United Arab Emirates (UAE). Using a quantitative, correlational research design this study administered the Entrepreneurial Intentions Questionnaire (EIQ), to a sample of 74 business students from the Higher Colleges of Technology (HCT), Sharjah Campuses. Descriptive statistics, correlational analysis and regression models were used to analyse and evaluate hypotheses. Findings confirm a high degree of entrepreneurial intentions among Emirati undergraduates, explained by a combination of motivational and environmental variables. Emirati Business students value capabilities over social approval to opt for starting an entrepreneurial venture. Students’ entrepreneurial intentions strongly correlated with perceptions of capabilities, which signals significant implications for practitioners. The paper suggests a clear focus on enhancing entrepreneurial capabilities is an effective avenue to cultivate entrepreneurial intentions and foster entrepreneurial action. Although previous studies in the UAE context highlighted high levels of entrepreneurial intentions, understanding of which factors influence these intentions was lacking. This paper makes significant contributions to filling this gap.
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