Astrophysics at St.Andrews
Lead Research Organisation:
University of St Andrews
Department Name: Physics and Astronomy
Abstract
Our Galaxy contains many fossils of its formation history. Smaller galaxies that collided with the Milky Way long ago formed streams of stars that still linger as fossils of the Galaxy's formation, orbiting in the gravitational field of the Galaxy's primordial dark-matter halo. From 2011 the GAIA mission will map the positions and motions of these streams. We will develop new techniques to use data from GAIA to map the dark matter, and to test whether conventional theories of gravity work as expected at large distances. Clusters of new stars and planetary systems are constantly forming inside the dark clouds of gas and dust that delineate the Milky Way's spiral arms. In the biggest clusters, stars form that are up to 100 times as massive as the Sun. These massive stars burn so brightly that they are clearly visible in neighbouring galaxies. Many of them are binary stars. Our measurements of their mutual eclipses and spectra will reveal their sizes and temperatures, and hence the distances to the nearest galaxies. We do not yet understand how these massive stars form, or why so many of them are binaries. We will simulate how the most massive and hottest stars manage to form despite the tendency of their radiation fields to blow away the gas that feeds them. We also aim to find out how their winds, and the shock waves from the supernova explosions that eventually blow them apart, affect neighbouring gas clouds, perhaps triggering new bursts of star formation. The dark clouds where stars form contain needle-like dust grains that line up with the Galaxy's magnetic fields and polarize radiation passing through them. We will measure the polarization of infrared and mm-wave radiation coming from regions where cloud material is just beginning to form new stars, to discover what is happening to the magnetic field and to the grains themselves as the star condenses. Newly-born stars are surrounded by flat, rotating discs of gas and dust, which persist for two or three million years. As planets form in the disc material, some gas continues to feed the growing star, which at this stage possesses a strong magnetic field. We can now map these stars' magnetic fields using new instruments. We will use these maps to predict how the magnetic field acts to channel material into streams, and how the field structure regulates the flow rate on to the star and the star's spin. We will seek out rapidly rotating young stars near the Sun, in remnants of star clusters that formed up to 50 million years ago but fell apart. By this age the discs have gone, but an enigmatic fossil remnant of earlier processes lingers in their spin rates. Among otherwise identical stars in the same cluster, some spin much faster than others. We want to know if this difference in spin rate is a clue as to how many stars possess planetary systems, or if the difference originates in some peculiarity of the stars' magnetic fields. We will map the magnetic fields of the fast rotators and their more slowly-rotating siblings, to see if there is a difference in the rate at which hot gas flowing out along the field lines can carry away the star's spin. Finally, we will seek out planetary systems around nearby and distant stars. We are working with astronomers at several other institutions to monitor the brightnesses of hundreds of thousands of nearby stars, in order to pick out tiny dips in light caused by close-orbiting Jupiter-sized planets passing in front of their parent stars. We aim to discover dozens of such planets, and to measure their sizes, masses and temperatures. We will also search for planets further from their stars, by monitoring distant stars whose light is being temporarily magnified by the gravitational field of a foreground star. Distortions in the resulting light variation have already revealed Jupiter-mass planets around a couple of these foreground stars. We aim to find many more using a network of new robotic telescopes.
Organisations
Publications
Gentile G
(2008)
Neutrinos as galactic dark matter in the Ursa Major galaxy group?
in Monthly Notices of the Royal Astronomical Society: Letters
Gentile G
(2007)
Tidal dwarf galaxies as a test of fundamental physics
in Astronomy & Astrophysics
Getman K
(2008)
X-Ray Flares in Orion Young Stars. II. Flares, Magnetospheres, and Protoplanetary Disks
in The Astrophysical Journal
Gettel S
(2016)
THE KEPLER-454 SYSTEM: A SMALL, NOT-ROCKY INNER PLANET, A JOVIAN WORLD, AND A DISTANT COMPANION
in The Astrophysical Journal
Gillon M
(2009)
Discovery and characterization of WASP-6b, an inflated sub-Jupiter mass planet transiting a solar-type star
in Astronomy & Astrophysics
Gould A
(2009)
THE EXTREME MICROLENSING EVENT OGLE-2007-BLG-224: TERRESTRIAL PARALLAX OBSERVATION OF A THICK-DISK BROWN DWARF
in The Astrophysical Journal
Gould A
(2006)
Microlens OGLE-2005-BLG-169 Implies That Cool Neptune-like Planets Are Common
in The Astrophysical Journal
Greaves J
(2009)
Debris discs around nearby solar analogues
in Monthly Notices of the Royal Astronomical Society
Greaves J
(2006)
Space debris and planet detection
in Astronomy and Geophysics
Greaves J
(2009)
Millimetre observations of Pleiades stars: a lack of solar-analogue planetesimal discs at 100 Myr?
in Monthly Notices of the Royal Astronomical Society: Letters
Greaves J
(2008)
Enhanced dust emission in the HL Tau disc: a low-mass companion in formation?
in Monthly Notices of the Royal Astronomical Society: Letters
Greaves J
(2006)
Metallicity, debris discs and planets
in Monthly Notices of the Royal Astronomical Society
Greaves J
(2007)
Predicting the frequencies of diverse exo-planetary systems
in Monthly Notices of the Royal Astronomical Society: Letters
Gregory S
(2016)
The influence of radiative core growth on coronal X-ray emission from pre-main-sequence stars
in Monthly Notices of the Royal Astronomical Society
Gregory S
(2006)
Rotationally modulated X-ray emission from T Tauri stars
in Monthly Notices of the Royal Astronomical Society
Gregory S
(2007)
Why are accreting T Tauri stars observed to be less luminous in X-rays than non-accretors?
in Monthly Notices of the Royal Astronomical Society: Letters
Gregory S
(2009)
The magnetic fields of accreting T Tauri stars
Gregory S
(2008)
The non-dipolar magnetic fields of accreting T Tauri stars The non-dipolar fields of T Tauri stars
in Monthly Notices of the Royal Astronomical Society
Gregory S
(2006)
Mass accretion on to T Tauri stars
in Monthly Notices of the Royal Astronomical Society
Gregory, S
(2009)
Multi-wavelength observing of a forming solar-like star
in High Resolution X-ray Spectroscopy: Towards IXO Proceedings of the international workshop held at the Mullard Space Science Laboratory of University College London, Holmbury St Mary, Dorking, Surrey, UK, March 19 - 20, 2009
Grunblatt S
(2015)
DETERMINING THE MASS OF KEPLER-78b WITH NONPARAMETRIC GAUSSIAN PROCESS ESTIMATION
in The Astrophysical Journal
Gu S
(2007)
Photometric follow-up observation of some SuperWASP transiting planet candidates
in Proceedings of the International Astronomical Union
Gómez Maqueo Chew Y
(2014)
The EBLM project II. A very hot, low-mass M dwarf in an eccentric and long-period, eclipsing binary system from the SuperWASP Survey?
in Astronomy & Astrophysics
Haffner L
(2009)
The warm ionized medium in spiral galaxies
in Reviews of Modern Physics
Halle A
(2008)
A Nonuniform Dark Energy Fluid: Perturbation Equations
in The Astrophysical Journal Supplement Series
Han C
(2009)
INTERPRETATION OF STRONG SHORT-TERM CENTRAL PERTURBATIONS IN THE LIGHT CURVES OF MODERATE-MAGNIFICATION MICROLENSING EVENTS
in The Astrophysical Journal
Hay K
(2016)
WASP-92b, WASP-93b and WASP-118b: three new transiting close-in giant planets
in Monthly Notices of the Royal Astronomical Society
Haywood R
(2016)
The Sun as a planet-host star: proxies from SDO images for HARPS radial-velocity variations
in Monthly Notices of the Royal Astronomical Society
Hebb L
(2009)
WASP-12b: THE HOTTEST TRANSITING EXTRASOLAR PLANET YET DISCOVERED
in The Astrophysical Journal
Hellier C
(2009)
An orbital period of 0.94 days for the hot-Jupiter planet WASP-18b.
in Nature
Hellier C
(2009)
WASP-7: A BRIGHT TRANSITING-EXOPLANET SYSTEM IN THE SOUTHERN HEMISPHERE
in The Astrophysical Journal
Hellier C
(2015)
THREE WASP-SOUTH TRANSITING EXOPLANETS: WASP-74b, WASP-83b, AND WASP-89b
in The Astronomical Journal
Hilditch R
(2006)
Eclipsing Binaries in Local Group Galaxies
in Astrophysics and Space Science
Hilditch R. W.
(2007)
Astrophysical parameters forthe eclipsing binary IZ Persei
in OBSERVATORY
Holzwarth V
(2006)
Theoretical mass loss rates of cool main-sequence stars
in Astronomy & Astrophysics
Holzwarth V
(2006)
The impact of meridional circulation on stellar butterfly diagrams and polar caps Stellar butterfly diagrams and polar caps
in Monthly Notices of the Royal Astronomical Society
Holzwarth V
(2007)
Formation of polar starspots through meridional circulation
in Astronomische Nachrichten
Hong-Bo T
(2014)
Photometric Observation and Study of the Transiting Exoplanetary System HAT-P-8
in Chinese Astronomy and Astrophysics
Hood B
(2008)
Reflected light from 3D exoplanetary atmospheres and simulation of HD 209458b
in Monthly Notices of the Royal Astronomical Society
Horne K
(2006)
X-ray gas in the galaxy cluster Abell 2029: conformal gravity versus dark matter Conformal gravity analysis of Abell 2029
in Monthly Notices of the Royal Astronomical Society
Howard C
(2008)
The Bulge Radial Velocity Assay (BRAVA). I. Sample Selection and a Rotation Curve
in The Astrophysical Journal
Howard C
(2009)
KINEMATICS AT THE EDGE OF THE GALACTIC BULGE: EVIDENCE FOR CYLINDRICAL ROTATION
in The Astrophysical Journal
Hussain G
(2009)
Surface magnetic fields on two accreting T Tauri stars: CV Cha and CR Cha
in Monthly Notices of the Royal Astronomical Society
Hussain G
(2007)
The coronal structure of AB Doradus determined from contemporaneous Doppler imaging and X-ray spectroscopy
in Monthly Notices of the Royal Astronomical Society
Hynes R
(2006)
Multiwavelength Observations of EXO 0748-676. I. Reprocessing of X-Ray Bursts
in The Astrophysical Journal
Indebetouw R
(2006)
Three-dimensional Models of Embedded High-Mass Stars: Effects of a Clumpy Circumstellar Medium
in The Astrophysical Journal
Jardine M
(2008)
Stellar mass ejections
in Proceedings of the International Astronomical Union
Jardine M
(2006)
X-ray emission from T Tauri stars
in Monthly Notices of the Royal Astronomical Society
Jardine M
(2008)
Radio emission from exoplanets: the role of the stellar coronal density and magnetic field strength
in Astronomy & Astrophysics
Jardine M
(2008)
Magnetic coronae of active main-sequence stars
in Proceedings of the International Astronomical Union
Description | Not applicable this year |
Exploitation Route | Not applicable this year |
Sectors | Education |