130 research outputs found
The Case for Asymmetric Dust Around a C-Rich AGB star
JHKL observations of the mass-losing carbon Mira variable IRAS 15194-5115 (II
Lup) extending over about 18 years are presented and discussed. The pulsation
period is 575 days and has remained essentially constant over this time span.
The star has undergone an extensive obscuration minimum during this time. This
is complex and, like such minima in similar objects, e.g. R For, does not fit
the model predictions of a simple long term periodicity. Together with the high
resolution observations of Lopez et al. the results suggest that the
obscuration changes are due to the formation of dust clouds of limited extent
in the line-of-sight. This is an RCB-type model. The effective reddening law at
J and H is similar to that found for R For.Comment: 8 pages, 2 figures, accepted for publication in MNRA
Capacity Enhancement in Digital Humanities in the United Kingdom and Ireland: Training and Beyond
This first discussion paper, produced by the UK-Ireland Digital Humanities Network in consultation with the wider Digital Humanities (DH) community in the two countries and beyond, summarises the findings of a) the first workshop organised by the network and b) the post-workshop survey and offers recommendations based on these findings
Communicating the Value and Impact of Digital Humanities in Teaching, Research, and Infrastructure Development
This is the second discussion paper produced by the UK-Ireland Digital Humanities Network in consultation with the wider Digital Humanities (DH) Community in the two countries and beyond. It summarises the findings of the second workshop organised by the network, and offers recommendations based on these findings
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
A pair of TESS planets spanning the radius valley around the nearby mid-M dwarf LTT 3780
We present the confirmation of two new planets transiting the nearby mid-M
dwarf LTT 3780 (TIC 36724087, TOI-732, , , =0.374
R, =0.401 M, d=22 pc). The two planet candidates are
identified in a single TESS sector and are validated with reconnaissance
spectroscopy, ground-based photometric follow-up, and high-resolution imaging.
With measured orbital periods of days, days and sizes
R, R, the
two planets span the radius valley in period-radius space around low mass stars
thus making the system a laboratory to test competing theories of the emergence
of the radius valley in that stellar mass regime. By combining 63 precise
radial-velocity measurements from HARPS and HARPS-N, we measure planet masses
of M and
M, which indicates that LTT 3780b has a bulk composition consistent
with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope.
We show that the recovered planetary masses are consistent with predictions
from both photoevaporation and from core-powered mass loss models. The
brightness and small size of LTT 3780, along with the measured planetary
parameters, render LTT 3780b and c as accessible targets for atmospheric
characterization of planets within the same planetary system and spanning the
radius valley.Comment: Accepted to AJ. 8 figures, 6 tables. CSV file of the RV measurements
(i.e. Table 2) are included in the source cod
The L 98-59 System: Three Transiting, Terrestrial-size Planets Orbiting a Nearby M Dwarf
We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia-measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the corresponding stellar parameters yield planet radii ranging from 0.8 R ⊕ to 1.6 R ⊕. All three planets have short orbital periods, ranging from 2.25 to 7.45 days with the outer pair just wide of a 2:1 period resonance. Diagnostic tests produced by the TESS Data Validation Report and the vetting package DAVE rule out common false-positive sources. These analyses, along with dedicated follow-up and the multiplicity of the system, lend confidence that the observed signals are caused by planets transiting L 98-59 and are not associated with other sources in the field. The L 98-59 system is interesting for a number of reasons: the host star is bright (V = 11.7 mag, K = 7.1 mag) and the planets are prime targets for further follow-up observations including precision radial-velocity mass measurements and future transit spectroscopy with the James Webb Space Telescope; the near-resonant configuration makes the system a laboratory to study planetary system dynamical evolution; and three planets of relatively similar size in the same system present an opportunity to study terrestrial planets where other variables (age, metallicity, etc.) can be held constant. L 98-59 will be observed in four more TESS sectors, which will provide a wealth of information on the three currently known planets and have the potential to reveal additional planets in the system
Competition and Combative Advertising: An Historical Analysis
Fred K. Beard (PhD, University of Oklahoma) is a professor of advertising in the Gaylord College of Journalism and Mass Communication, University of Oklahoma. His research interests include comparative advertising, advertising humor, and advertising history. His work has appeared in the Journal of Advertising, the Journal of Advertising Research, the Journal of Business Ethics, the Journal of Business Research, Journalism History, the Journal of Historical Research in Marketing, the Journal of Macromarketing, and the Journal of Marketing Communications, among others.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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