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
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
Gu S
(2007)
Photometric follow-up observation of some SuperWASP transiting planet candidates
in Proceedings of the International Astronomical Union
Grunblatt S
(2015)
DETERMINING THE MASS OF KEPLER-78b WITH NONPARAMETRIC GAUSSIAN PROCESS ESTIMATION
in The Astrophysical Journal
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
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
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
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
Gillon M
(2009)
Discovery and characterization of WASP-6b, an inflated sub-Jupiter mass planet transiting a solar-type star
in Astronomy & Astrophysics
Gettel S
(2016)
THE KEPLER-454 SYSTEM: A SMALL, NOT-ROCKY INNER PLANET, A JOVIAN WORLD, AND A DISTANT COMPANION
in The Astrophysical Journal
Getman K
(2008)
X-Ray Flares in Orion Young Stars. II. Flares, Magnetospheres, and Protoplanetary Disks
in The Astrophysical Journal
Gentile G
(2009)
Universality of galactic surface densities within one dark halo scale-length.
in Nature
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
Gaudi B
(2008)
Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing
in Science
Fynbo JP
(2006)
No supernovae associated with two long-duration gamma-ray bursts.
in Nature
Fiori E
(2017)
Letter regarding 'Covered versus uncovered metal stents for malignant gastric outlet obstruction: Systematic review and meta-analysis'.
in Digestive endoscopy : official journal of the Japan Gastroenterological Endoscopy Society
Feix M
(2008)
Is Gravitational Lensing by Intercluster Filaments Always Negligible?
in The Astrophysical Journal
Faria J
(2016)
Uncovering the planets and stellar activity of CoRoT-7 using only radial velocities
in Astronomy & Astrophysics
Fares R
(2013)
A small survey of the magnetic fields of planet-host stars?
in Monthly Notices of the Royal Astronomical Society
Fares R
(2009)
Magnetic cycles of the planet-hosting star t Bootis - II. A second magnetic polarity reversal
in Monthly Notices of the Royal Astronomical Society
Famaey B
(2007)
Escaping from modified Newtonian dynamics
in Monthly Notices of the Royal Astronomical Society: Letters
Famaey B
(2007)
Insight into the baryon-gravity relation in galaxies
in Physical Review D
Díaz R
(2016)
The HARPS search for southern extra-solar planets XXXVIII. Bayesian re-analysis of three systems. New super-Earths, unconfirmed signals, and magnetic cycles ???
in Astronomy & Astrophysics
Dunstone N
(2008)
Differential rotation on both components of the pre-main-sequence binary system HD 155555
in Monthly Notices of the Royal Astronomical Society
Dunstone N
(2006)
The coronal structure of Speedy Mic - II. Prominence masses and off-disc emission*
in Monthly Notices of the Royal Astronomical Society
Dunstone N
(2008)
The first magnetic maps of a pre-main-sequence binary star system - HD 155555
in Monthly Notices of the Royal Astronomical Society
Dunstone N
(2006)
The coronal structure of Speedy Mic -- I. A densely packed prominence system beyond corotation
in Monthly Notices of the Royal Astronomical Society
Dumusque X
(2017)
Radial-velocity fitting challenge II. First results of the analysis of the data set?
in Astronomy & Astrophysics
Dumusque X
(2015)
HARPS-N OBSERVES THE SUN AS A STAR
in The Astrophysical Journal
Dressing C
(2015)
THE MASS OF Kepler-93b AND THE COMPOSITION OF TERRESTRIAL PLANETS
in The Astrophysical Journal
Donati JF
(2006)
The large-scale axisymmetric magnetic topology of a very-low-mass fully convective star.
in Science (New York, N.Y.)
Donati J
(2008)
Large-scale magnetic topologies of early M dwarfs ?
in Monthly Notices of the Royal Astronomical Society
Donati J
(2017)
The hot Jupiter of the magnetically active weak-line T Tauri star V830 Tau
in Monthly Notices of the Royal Astronomical Society
Donati J
(2007)
Magnetic fields and accretion flows on the classical T Tauri star V2129 Oph*
in Monthly Notices of the Royal Astronomical Society
Donati J
(2008)
Magnetospheric accretion on the T Tauri star BP Tauri
in Monthly Notices of the Royal Astronomical Society
Donati J
(2014)
Modelling the magnetic activity and filtering radial velocity curves of young Suns : the weak-line T Tauri star LkCa 4
in Monthly Notices of the Royal Astronomical Society
Donati J
(2008)
Magnetic cycles of the planet-hosting star t Bootis
in Monthly Notices of the Royal Astronomical Society
Donati J
(2006)
The surprising magnetic topology of Sco: fossil remnant or dynamo output?
in Monthly Notices of the Royal Astronomical Society
Dominik M
(2007)
Adaptive contouring - an efficient way to calculate microlensing light curves of extended sources
in Monthly Notices of the Royal Astronomical Society
Description | Not applicable this year |
Exploitation Route | Not applicable this year |
Sectors | Education |