51 research outputs found
Exploring Chinese students’ experience of curriculum internationalisation: a comparative study of Scotland and Australia
Increasing enrolment of Chinese students has become a key feature of internationalisation for Western universities, but there is limited research into how curriculum internationalisation affects Chinese students’ learning experiences. Using the typologies of curriculum internationalisation (Edwards et al, 2003) as a framework, this paper explores and compares how Scottish and Australian universities integrate international and intercultural elements into their curriculum to support Chinese postgraduate taught students’ study. Interviews, focus groups and a survey are used as the main research methods. Analysis reveals that the practice of curriculum internationalisation in both countries is rather limited, and that Chinese students express a desire for more international perspectives in the course content, and for more mobility experiences, in order to prepare for their future careers. The mismatch between academics’ and students’ understandings of curriculum internationalisation is highlighted as an arena of power differential and an area for further study
Exoplanet Catalogues
One of the most exciting developments in the field of exoplanets has been the
progression from 'stamp-collecting' to demography, from discovery to
characterisation, from exoplanets to comparative exoplanetology. There is an
exhilaration when a prediction is confirmed, a trend is observed, or a new
population appears. This transition has been driven by the rise in the sheer
number of known exoplanets, which has been rising exponentially for two decades
(Mamajek 2016). However, the careful collection, scrutiny and organisation of
these exoplanets is necessary for drawing robust, scientific conclusions that
are sensitive to the biases and caveats that have gone into their discovery.
The purpose of this chapter is to discuss and demonstrate important
considerations to keep in mind when examining or constructing a catalogue of
exoplanets. First, we introduce the value of exoplanetary catalogues. There are
a handful of large, online databases that aggregate the available exoplanet
literature and render it digestible and navigable - an ever more complex task
with the growing number and diversity of exoplanet discoveries. We compare and
contrast three of the most up-to-date general catalogues, including the data
and tools that are available. We then describe exoplanet catalogues that were
constructed to address specific science questions or exoplanet discovery space.
Although we do not attempt to list or summarise all the published lists of
exoplanets in the literature in this chapter, we explore the case study of the
NASA Kepler mission planet catalogues in some detail. Finally, we lay out some
of the best practices to adopt when constructing or utilising an exoplanet
catalogue.Comment: 14 pages, 6 figures. Invited review chapter, to appear in "Handbook
of Exoplanets", edited by H.J. Deeg and J.A. Belmonte, section editor N.
Batalh
Probing the close environment of young stellar objects with interferometry
The study of Young Stellar Objects (YSOs) is one of the most exciting topics
that can be undertaken by long baseline optical interferometry. The magnitudes
of these objects are at the edge of capabilities of current optical
interferometers, limiting the studies to a few dozen, but are well within the
capability of coming large aperture interferometers like the VLT
Interferometer, the Keck Interferometer, the Large Binocular Telescope or
'OHANA. The milli-arcsecond spatial resolution reached by interferometry probes
the very close environment of young stars, down to a tenth of an astronomical
unit. In this paper, I review the different aspects of star formation that can
be tackled by interferometry: circumstellar disks, multiplicity, jets. I
present recent observations performed with operational infrared
interferometers, IOTA, PTI and ISI, and I show why in the next future one will
extend these studies with large aperture interferometers.Comment: Review to be published in JENAM'2002 proceedings "The Very Large
Telescope Interferometer Challenges for the future
Accreting Protoplanets in the LkCa 15 Transition Disk
Exoplanet detections have revolutionized astronomy, offering new insights
into solar system architecture and planet demographics. While nearly 1900
exoplanets have now been discovered and confirmed, none are still in the
process of formation. Transition discs, protoplanetary disks with inner
clearings best explained by the influence of accreting planets, are natural
laboratories for the study of planet formation. Some transition discs show
evidence for the presence of young planets in the form of disc asymmetries or
infrared sources detected within their clearings, as in the case of LkCa 15.
Attempts to observe directly signatures of accretion onto protoplanets have
hitherto proven unsuccessful. Here we report adaptive optics observations of
LkCa 15 that probe within the disc clearing. With accurate source positions
over multiple epochs spanning 2009 - 2015, we infer the presence of multiple
companions on Keplerian orbits. We directly detect H{\alpha} emission from the
innermost companion, LkCa 15 b, evincing hot (~10,000 K) gas falling deep into
the potential well of an accreting protoplanet.Comment: 35 pages, 3 figures, 1 table, 9 extended data item
SPECULOOS exoplanet search and its prototype on TRAPPIST
One of the most significant goals of modern science is establishing whether
life exists around other suns. The most direct path towards its achievement is
the detection and atmospheric characterization of terrestrial exoplanets with
potentially habitable surface conditions. The nearest ultracool dwarfs (UCDs),
i.e. very-low-mass stars and brown dwarfs with effective temperatures lower
than 2700 K, represent a unique opportunity to reach this goal within the next
decade. The potential of the transit method for detecting potentially habitable
Earth-sized planets around these objects is drastically increased compared to
Earth-Sun analogs. Furthermore, only a terrestrial planet transiting a nearby
UCD would be amenable for a thorough atmospheric characterization, including
the search for possible biosignatures, with near-future facilities such as the
James Webb Space Telescope. In this chapter, we first describe the physical
properties of UCDs as well as the unique potential they offer for the detection
of potentially habitable Earth-sized planets suitable for atmospheric
characterization. Then, we present the SPECULOOS ground-based transit survey,
that will search for Earth-sized planets transiting the nearest UCDs, as well
as its prototype survey on the TRAPPIST telescopes. We conclude by discussing
the prospects offered by the recent detection by this prototype survey of a
system of seven temperate Earth-sized planets transiting a nearby UCD,
TRAPPIST-1.Comment: Submitted as a chapter in the "Handbook of Exoplanets" (editors: H.
Deeg & J.A. Belmonte; Section Editor: N. Narita). 16 pages, 4 figure
A rocky planet transiting a nearby low-mass star
M-dwarf stars -- hydrogen-burning stars that are smaller than 60 per cent of
the size of the Sun -- are the most common class of star in our Galaxy and
outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M
dwarfs host Earth-sized planets in great numbers: the average number of M-dwarf
planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per
star. The nearest such planets known to transit their star are 39 parsecs away,
too distant for detailed follow-up observations to measure the planetary masses
or to study their atmospheres. Here we report observations of GJ 1132b, a
planet with a size of 1.2 Earth radii that is transiting a small star 12
parsecs away. Our Doppler mass measurement of GJ 1132b yields a density
consistent with an Earth-like bulk composition, similar to the compositions of
the six known exoplanets with masses less than six times that of the Earth and
precisely measured densities. Receiving 19 times more stellar radiation than
the Earth, the planet is too hot to be habitable but is cool enough to support
a substantial atmosphere, one that has probably been considerably depleted of
hydrogen. Because the host star is nearby and only 21 per cent the radius of
the Sun, existing and upcoming telescopes will be able to observe the
composition and dynamics of the planetary atmosphere.Comment: Published in Nature on 12 November 2015, available at
http://dx.doi.org/10.1038/nature15762. This is the authors' version of the
manuscrip
Misaligned Protoplanetary Disks in a Young Binary System
Many extrasolar planets follow orbits that differ from the nearly coplanar
and circular orbits found in our solar system; orbits may be eccentric or
inclined with respect to the host star's equator, and the population of giant
planets orbiting close to their host stars suggests significant orbital
migration. There is currently no consensus on what produces such orbits.
Theoretical explanations often invoke interactions with a binary companion star
on an orbit that is inclined relative to the planet's orbital plane. Such
mechanisms require significant mutual inclinations between planetary and binary
star orbital planes. The protoplanetary disks in a few young binaries are
misaligned, but these measurements are sensitive only to a small portion of the
inner disk, and the three-dimensional misalignment of the bulk of the
planet-forming disk mass has hitherto not been determined. Here we report that
the protoplanetary disks in the young binary system HK Tau are misaligned by
60{\deg}-68{\deg}, so one or both disks are significantly inclined to the
binary orbital plane. Our results demonstrate that the necessary conditions
exist for misalignment-driven mechanisms to modify planetary orbits, and that
these conditions are present at the time of planet formation, apparently due to
the binary formation process.Comment: Published in Nature, July 31 2014. 18 pages. This version has slight
differences from the final published version. Final version is available at
http://www.nature.com/nature/journal/v511/n7511/full/nature13521.htm
Discovery of molecular hydrogen in a high-velocity cloud of the Galactic halo
We report the discovery of molecular hydrogen absorption in a Galactic
high-velocity cloud (HVC) in the direction of the Large Magellanic Cloud. For
the same HVC we derive an iron abundance which is half of the solar value.
Thus, all evidence points to a Galactic origin for high-velocity cloud complex
in front of the LMC.Comment: Published in Nature, this week; 14 pages, 3 figure
Planetary Dynamics and Habitable Planet Formation In Binary Star Systems
Whether binaries can harbor potentially habitable planets depends on several
factors including the physical properties and the orbital characteristics of
the binary system. While the former determines the location of the habitable
zone (HZ), the latter affects the dynamics of the material from which
terrestrial planets are formed (i.e., planetesimals and planetary embryos), and
drives the final architecture of the planets assembly. In order for a habitable
planet to form in a binary star system, these two factors have to work in
harmony. That is, the orbital dynamics of the two stars and their interactions
with the planet-forming material have to allow terrestrial planet formation in
the habitable zone, and ensure that the orbit of a potentially habitable planet
will be stable for long times. We have organized this chapter with the same
order in mind. We begin by presenting a general discussion on the motion of
planets in binary stars and their stability. We then discuss the stability of
terrestrial planets, and the formation of potentially habitable planets in a
binary-planetary system.Comment: 56 pages, 29 figures, chapter to appear in the book: Planets in
Binary Star Systems (Ed. N. Haghighipour, Springer publishing company
A dusty torus around the luminous young star LkHa 101
A star forms when a cloud of dust and gas collapses. It is generally believed
that this collapse first produces a flattened rotating disk, through which
matter is fed onto the embryonic star at the center of the disk. When the
temperature and density at the center of the star pass a critical threshold,
thermonuclear fusion begins. The remaining disk, which can still contain up to
0.3 times the mass of the star, is then sculpted and eventually dissipated by
the radiation and wind from the newborn star. Unfortunately this picture of the
structure and evolution of the disk remains speculative because of the lack of
morphological data of sufficient resolution and uncertainties regarding the
underlying physical processes. Here we present resolved images of a young star,
LkHa 101 in which the structure of the inner accretion disk is resolved. We
find that the disk is almost face-on, with a central gap (or cavity) and a hot
inner edge. The cavity is bigger than previous theoretical predictions, and we
infer that the position of the inner edge is probably determined by sublimation
of dust grains by direct stellar radiation, rather than by disk reprocessing or
the viscous heating processes as usually assumed.Comment: 7 pages, 1 figure. Appears in Nature, 22 Feb, 2001 (Vol 409
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