976 research outputs found

    A search for hidden white dwarfs in the ROSAT EUV survey II: Discovery of a distant DA+F6/7V binary system in a direction of low density neutral hydrogen

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    We report the results of our final search for hot white dwarfs in unresolved, Sirius-type, binary systems with IUE. One new system, RE J0500-364 (DA+F6/7V), has been identified. This star appears to lie at a distance of between 500-1000pc, making it one of the most distant white dwarfs, if not the most distant, to be detected in the EUV surveys. The very low line-of-sight neutral hydrogen volume density to this object could place a lower limit on the length of the Beta CMa interstellar tunnel of diffuse gas, which stretches away from the Local Bubble in a similar direction to RE J0500-364.Comment: 1 LaTex file plus 15 figures; accepted for publication in Monthly Notices of the Royal Astronomical Societ

    Some American Dolomites

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    These rocks are among the important building materials of the country and have a wide distribution. We secured a few typical specimens from different sections, in order to make a comparison of their chemical composition. The specimens analyzed are all used as building stones in their respective localities

    Hubble Space Telescope Imaging and Spectroscopy of the Sirius-Like Triple Star System HD 217411

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    We present Hubble Space Telescope imaging and spectroscopy of HD 217411, a G3 V star associated with the extreme ultraviolet excess source (EUV 2RE J2300-07.0). This star is revealed to be a triple system with a G 3V primary (HD 217411 A) separated by ~1.1" from a secondary that is in turn composed of an unresolved K0 V star (HD 217411 Ba) and a hot DA white dwarf (HD 217411 Bb). The hot white dwarf dominates the UV flux of the system. However; it is in turn dominated by the K0 V component beyond 3000 {\AA}. A revised distance of 143 pc is estimated for the system. A low level photometric modulation having a period of 0.61 days has also been observed in this system along with a rotational velocity on the order of 60 km s-1 in the K0 V star. Together both observations point to a possible wind induced spin up of the K0 V star during the AGB phase of the white dwarf. The nature of all three components is discussed as are constraints on the orbits, system age and evolution.Comment: 11 pages, 6 figure

    A Near-Infrared Spectroscopic Study of the Accreting Magnetic White Dwarf SDSS J121209.31+013627.7 and its Substellar Companion

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    The nature of the excess near-infrared emission associated with the magnetic white dwarf commonly known as SDSS 1212 is investigated primarily through spectroscopy, and also via photometry. The inferred low mass secondary in this system has been previously detected by the emission and variation of Hα\alpha, and the 1−2.51-2.5 μ\mum spectral data presented here are consistent with the presence of a late L or early T dwarf. The excess flux seen beyond 1.5 μ\mum in the phase-averaged spectrum is adequately modeled with an L8 dwarf substellar companion and cyclotron emission in a 7 MG magnetic field. This interesting system manifests several observational properties typical of polars, and is most likely an old interacting binary with a magnetic white dwarf and a substellar donor in an extended low state.Comment: 28 pages, 5 figures, Accepted to Ap

    Online Adjunct Faculty Perceptions of Professional Development to Support Personal and Professional Academic Growth During COVID-19

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    Objective: The purpose of this study was to understand what online adjunct faculty value as support services, specifically professional development opportunities, provided by their respective higher education institutions. Method: This qualitative narrative inquiry study centered on exploring perceptions and experiences of online adjunct faculty members from higher education institutions and their experiences and expectations of professional development (PD), prior to and during COVID-19. Results: The study resulted in the identification of possible improvements and enhancements to existing PD content that would further support faculty personal development, mental health, wellbeing, and academic growth. Conclusions: This study reminds us that there are numerous variables, including unforeseen crises such as the COVID-19 pandemic, that need to be considered when developing, implementing, and presenting PD for online adjunct faculty professional and personal growth. Because faculty want to be listened to and heard, the PD development and implementation process needs to be interactive to support online adjunct faculty, regardless of whether the university is for-profit or not-for-profit. Implication for Practice: The results based on online adjunct faculty experiences could lead to updating professional development opportunities employed in different higher education institutions to promote faculty self-actualization and ultimately, student success

    Considering Educators’ Perceptions of Ethics and Safety in Virtual Learning Environments (VLEs)

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    With the proliferation of students’ abilities to use technology, in particular virtual reality (VR) applications, teachers are experimenting with VR in virtual learning environments (VLE) to engage students; but clear ethics and safety guidelines are not available. Within the field of education additional research is needed to determine how VR is employed in VLEs. Additionally, what are the decision-making processes of educators for the VR programs chosen for classroom use based on ethics and student safety? Through qualitative inquiry, educators from K–12 and higher education shared their perceptions of ethics and safety concerns in VR applications for use in the classroom. We collected data from a sample of K–12 and higher education professionals from the Association for Educational Communications and Technology (AECT) membership, an educational organization emphasizing technology integration and learning. Data analysis from the individual interviews with open-ended questions revealed five primary themes and twelve sub-themes. Participants agreed that they need ethical and safety guidelines as they embark on new horizons that influence student well-being. The findings from this study may provide an in-depth understanding of the importance of developing ethics and safety guidelines for educational VR programs when used by students
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