Textiles, connection and meaning

Why do some items of clothing remain safely housed in our wardrobes whilst others are quickly relegated to opportunity shops? This paper will investigate the practical, emotional and nostalgic connections people make with their possessions. This understanding will be used to suggest ways in which we can better design and promote textiles for the fashion market. Textiles for the body can be functional, fashionable, symbolic or a combination of the three. The method of ‘slow design’ will be used, as a vehicle to explore ways that ensure textiles meet the practical and emotional needs of consumers for the long term. Slow design follows a holistic approach where each stage of the design process is carefully considered. Bespoke, well-crafted design can be appreciated on a variety of levels increasing the bond between object and owner. A garment with cultural significance purchased whilst on holiday has an emotional advantage over a cheap poorly made garment purchased on a whim during lunch hour. The holiday purchase becomes a nostalgic reminder of travels, experiences and people. The cheap disposable garment has an immediate purpose, to protect, or to project an awareness and acceptance of fashion. Fast fashion is consumed in a similar way to fast food. Its job is to satisfy immediate needs, not to nourish long term. Opportunity shops are currently overwhelmed with cheap disposable fashion due to a continual wave of desire and disappointment. If designers can connect with people on multiple levels the desire for quantity over quality may be reversed and relieve the drain on resources

Binary Stars as the Source of the Far-UV Excess in Elliptical Galaxies

The discovery of an excess of light in the far-ultraviolet (UV) spectrum in elliptical galaxies was a major surprise in 1969. While it is now clear that this UV excess is caused by an old population of hot helium-burning stars without large hydrogen-rich envelopes rather than young stars, their origin has remained a mystery. Here we show that these stars most likely lost their envelopes because of binary interactions, similar to the hot subdwarf population in our own Galaxy. This has major implications for understanding the evolution of the UV excess and of elliptical galaxies in general. In particular, it implies that the UV excess is not a sign of age, as had been postulated previously, and predicts that it should not be strongly dependent on the metallicity of the population.Comment: Proceedings of Puerto Vallarta 07, "New Quests in Stellar Astrophysics. II. The Ultraviolet Properties of Evolved Stellar Populations", 6 pages, 2 figures. A much better version of Figure 1 can be obtained on reques

Orbital Characteristics of the Subdwarf-B and F V Star Binary EC~20117-4014(=V4640 Sgr)

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC~20117-4014 (=V4640~Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion (O'Donoghue et al. 1997), however the period and the orbit semi-major axes have not been precisely determined. This paper presents orbital characteristics of the EC 20117-4014 binary system using 20 years of photometric data. Periodic Observed minus Calculated (O-C) variations were detected in the two highest amplitude pulsations identified in the EC 20117-4014 power spectrum, indicating the binary system's precise orbital period (P = 792.3 days) and the light-travel time amplitude (A = 468.9 s). This binary shows no significant orbital eccentricity and the upper limit of the eccentricity is 0.025 (using 3 $\sigma$ as an upper limit). This upper limit of the eccentricity is the lowest among all wide sdB binaries with known orbital parameters. This analysis indicated that the sdB is likely to have lost its hydrogen envelope through stable Roche lobe overflow, thus supporting hypotheses for the origin of sdB stars. In addition to those results, the underlying pulsation period change obtained from the photometric data was $\dot{P}$ = 5.4 ($\pm$0.7) $\times$ $10^{-14}$ d d$^{-1}$, which shows that the sdB is just before the end of the core helium-burning phase

An investigation of galactic structure made from the study of the northern-hemisphere early type stars at intermediate galactic latitudes

Photometric and spectroscopic observations have been made of northern hemisphere early type stars at intermediate galactic latitudes. Stellar distances, the corresponding distances from the galactic plane and the interstellar reddening along the lines of sight have been derived. The available published data was used to support the observational results. The HI spiral features seem to have corresponding optical counterparts, and the agreement between the two patterns is remarkably good. The neutral hydrogen kinematic distances depart from the stellar distances. This can be explained in terms of the density wave theory, with a small modification which may be the result of a non-zero distance from the galactic plane. The Local Arm extends to about 500pc above the galactic plane and the Perseus Arm to 1 kpc. Thus it seems that the interpretation of intermediate latitude high and intermediate velocity features, as vertical extensions to the spiral arms in the galactic plane, may be correct. Stellar and interstellar calcium radial velocities suggest that these intermediate latitude spiral features adhere closely to differential galactic rotation, and that the small departures from this motion exhibit a significant correlation with the predictions of the density wave theory. Published proper motions are used together with the stellar radial velocities to derive the components of the stellar space motions with respect to their local standards of rest. In cases where the component normal to the galactic plane was significantly different from zero, the dynamical lifetime was calculated on the assumption that the star was formed in the galactic plane. These were found to be compatible with the evolutionary lifetimes for only half of the stars considered, suggesting that about 50% of intermediate latitude OB stars were formed in or near the galactic plane and subsequently ejected from it. The remainder seem to have been formed at considerable distances from the galactic plane, and a scheme for explaining this is proposed. This scheme also explains the apparent asymmetry between the northern and southern galactic hemispheres. A few interesting high velocity stars and OB star associations are also considered

Hot Subdwarfs in Binaries as the Source of the Far-UV Excess in Elliptical Galaxies

The excess of far-ultraviolet (far-UV) radiation in elliptical galaxies has remained one of their most enduring puzzles. In contrast, the origin of old blue stars in the Milky Way, hot subdwarfs, is now reasonably well understood: they are hot stars that have lost their hydrogen envelopes by various binary interactions. Here, we review the main evolutionary channels that produce hot subdwarfs in the Galaxy and present the results of binary population synthesis simulations that reproduce the main properties of the Galactic hot-subdwarf population. Applying the same model to elliptical galaxies, we show how this model can explain the main observational properties of the far-UV excess, including the far-UV spectrum, without the need to invoke ad hoc physical processes. The model implies that the UV excess is not a sign of age, as has been postulated previously, and predicts that it should not be strongly dependent on the metallicity of the population.Comment: 11 pages, 6 figures (preprint version

Exomol line lists – xliv. Infrared and ultraviolet line list for silicon monoxide (28si16o)

A new silicon monoxide ( 28Si16O) line list covering infrared, visible, and ultraviolet regions called SiOUVenIR is presented. This line list extends the infrared EBJT ExoMol line list by including vibronic transitions to the A 1 and E 1+ electronic states. Strong perturbations to the A 1 band system are accurately modelled through the treatment of six dark electronic states: C 1−, D 1 , a 3+, b 3, e 3−, and d 3 . Along with the X 1+ ground state, these nine electronic states were used to build a comprehensive spectroscopic model of SiO using a combination of empirical and ab initio curves, including the potential energy (PE), spin–orbit, electronic angular momentum, and (transition) dipole moment curves. The ab initio PE and coupling curves, computed at the multireference configuration interaction level of theory, were refined by fitting their analytical representations to 2617 experimentally derived SiO energy levels determined from 97 vibronic bands belonging to the X–X, E–X, and A–X electronic systems through the MARVEL (Measured Active Rotational–Vibrational Energy Levels) procedure. 112 observed forbidden transitions from the C–X, D–X, e–X, and d–X bands were assigned using our predictions, and these could be fed back into the MARVEL procedure. The SiOUVenIR line list was computed using published ab initio transition dipole moments for the E–X and A–X bands; the line list is suitable for temperatures up to 10 000 K and for wavelengths longer than 140 nm. SiOUVenIR is available from www.exomol.com and the CDS data base