Cathie Clarke

Last updated
Cathie Clarke
FRS
Born
Catherine Jane Clarke
Alma mater University of Oxford (DPhil)
Awards Eddington Medal (2017) [1]
Scientific career
Fields Star formation
Exoplanets
Institutions University of Cambridge
Thesis Accretion disc structure in binary star and galactic potentials  (1987)
Doctoral advisor Geoffrey Bath [2]
Doctoral students James E. Owen
Website www.ast.cam.ac.uk/people/cathie.j.clarke

Catherine Jane Clarke FRS is a Professor of Theoretical Astrophysics at the University of Cambridge and a fellow of Clare College, Cambridge. [3] In 2017 she became the first woman to be awarded the Eddington Medal by the Royal Astronomical Society. In 2022 she became the first female director of the Institute of Astronomy, Cambridge. [4]

Contents

Education

Clarke matriculated in 1980 to study the Natural Sciences tripos at Clare College, Cambridge where she completed her undergraduate education in 1983. She was subsequently educated at the University of Oxford where she received a Doctor of Philosophy degree in 1987 for research on binary stars supervised by Geoffrey Bath. [2] Her doctoral thesis was titled "Accretion disc structure in binary star and galactic potentials". [2]

Career and research

Clarke studies astrophysical fluid dynamics, including accretion and protoplanetary discs and stellar winds. She was the first to demonstrate how protoplanetary disc formation around low-mass young stars is determined by their radiation field. [1] This removes material from the disc and is integral for various models of planet formation and migration. [1] Clarke uses hydrodynamical simulations to study the physics of photoevaporation. [5] [6]

In 2001 she was awarded the University of Cambridge Pilkington Prize for teaching and learning. [7] She co-authored the Principles of Astrophysical Fluid Dynamics textbook with Bob Carswell in 2014. [8] It is a primer for the fluid dynamics required to understand astronomical phenomena. [8] She developed the course in 1996, and delivered it as part of Part II Astrophysics between 1996 and 1999. [8] She contributed to the book Dynamics of Young Star Clusters and Associations in 2015. [9]

Her recent work has combined analytical observation and hydrodynamical simulations in exoplanet discovery. [1] She demonstrated the first evidence of external disc photoevaporation in a low-mass star in 2017. The star studied was IM Lupi, which was shown to have a CO (carbon monoxide) halo that extends beyond 1,000 AU. [10]

Clarke identified a young star with four planets, the size of Jupiter and Saturn, in orbit around it. [11] The star, CI Tauri, hosts the first hot Jupiter candidate in a protoplanetary disc system. [12] She used the Atacama Large Millimeter Array to search for nearby planets. The closest is in an equivalent orbit to Mercury, whilst the furthest has an orbit three times that of Neptune. [12] The two outer planets are similar masses to the sun. [12] She demonstrated that proximity to nearby stars impacts the lifetime of protoplanetary discs. [13] [14] She serves as editor of the Elsevier Journal, New Astronomy Reviews. [15] She is a member of the International Astronomical Union.

Clarke's other research interests include self-gravity in disc evolution and formation of brown dwarfs in unstable multiple systems. [1]

Awards and honours

In 2017, Clarke was awarded the Eddington Medal by the Royal Astronomical Society; she is the first woman to win this medal. [1] She was elected a Fellow of the Royal Society in 2023. [16]

Publications

Related Research Articles

<span class="mw-page-title-main">Planetesimal</span> Solid objects in protoplanetary disks and debris disks

Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. Believed to have formed in the Solar System about 4.6 billion years ago, they aid study of its formation.

<span class="mw-page-title-main">Nebular hypothesis</span> Astronomical theory about the Solar System

The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System. It suggests the Solar System is formed from gas and dust orbiting the Sun which clumped up together to form the planets. The theory was developed by Immanuel Kant and published in his Universal Natural History and Theory of the Heavens (1755) and then modified in 1796 by Pierre Laplace. Originally applied to the Solar System, the process of planetary system formation is now thought to be at work throughout the universe. The widely accepted modern variant of the nebular theory is the solar nebular disk model (SNDM) or solar nebular model. It offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the original nebular theory are echoed in modern theories of planetary formation, but most elements have been superseded.

<span class="mw-page-title-main">Protoplanetary disk</span> Gas and dust surrounding a newly formed star

A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may also be considered an accretion disk for the star itself, because gases or other material may be falling from the inner edge of the disk onto the surface of the star. This process should not be confused with the accretion process thought to build up the planets themselves. Externally illuminated photo-evaporating protoplanetary disks are called proplyds.

<span class="mw-page-title-main">Proplyd</span> Dust ring surrounding large stars thousands of solar radii wide

A proplyd, short for ionized protoplanetary disk, is an externally illuminated photoevaporating protoplanetary disk around a young star. Nearly 180 proplyds have been discovered in the Orion Nebula. Images of proplyds in other star-forming regions are rare, while Orion is the only region with a large known sample due to its relative proximity to Earth.

Photoevaporation is the process where energetic radiation ionises gas and causes it to disperse away from the ionising source. The term is typically used in an astrophysical context where ultraviolet radiation from hot stars acts on clouds of material such as molecular clouds, protoplanetary disks, or planetary atmospheres.

<span class="mw-page-title-main">Accretion (astrophysics)</span> Accumulation of particles into a massive object by gravitationally attracting more matter

In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, into an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.

<span class="mw-page-title-main">Protoplanetary nebula</span> Nebula surrounding a dying star

A protoplanetary nebula or preplanetary nebula is an astronomical object which is at the short-lived episode during a star's rapid evolution between the late asymptotic giant branch (LAGB)[a] phase and the subsequent planetary nebula (PN) phase. A PPN emits strongly in infrared radiation, and is a kind of reflection nebula. It is the second-from-the-last high-luminosity evolution phase in the life cycle of intermediate-mass stars.

<span class="mw-page-title-main">Bipolar outflow</span> Two continuous flows of gas from the poles of a star

A bipolar outflow comprises two continuous flows of gas from the poles of a star. Bipolar outflows may be associated with protostars, or with evolved post-AGB stars.

HD 98800, also catalogued as TV Crateris, is a quadruple star system in the constellation of Crater. Parallax measurements made by the Hipparcos spacecraft put it at a distance of about 150 light-years away. The system is located within the TW Hydrae association (TWA), and has received the designation TWA 4.

<span class="mw-page-title-main">History of Solar System formation and evolution hypotheses</span>

The history of scientific thought about the formation and evolution of the Solar System began with the Copernican Revolution. The first recorded use of the term "Solar System" dates from 1704. Since the seventeenth century, philosophers and scientists have been forming hypotheses concerning the origins of our Solar System and the Moon and attempting to predict how the Solar System would change in the future. René Descartes was the first to hypothesize on the beginning of the Solar System; however, more scientists joined the discussion in the eighteenth century, forming the groundwork for later hypotheses on the topic. Later, particularly in the twentieth century, a variety of hypotheses began to build up, including the now-commonly accepted nebular hypothesis.

James Edward Pringle is a British astrophysicist. He is a professor of theoretical astronomy at the Institute of Astronomy, Cambridge part of the University of Cambridge.

<span class="mw-page-title-main">Accretion disk</span> Structure formed by diffuse material in orbital motion around a massive central body

An accretion disk is a structure formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward toward the central body. Gravitational and frictional forces compress and raise the temperature of the material, causing the emission of electromagnetic radiation. The frequency range of that radiation depends on the central object's mass. Accretion disks of young stars and protostars radiate in the infrared; those around neutron stars and black holes in the X-ray part of the spectrum. The study of oscillation modes in accretion disks is referred to as diskoseismology.

<span class="mw-page-title-main">Circumstellar disc</span> Accumulation of matter around a star

A circumstellar disc is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the reservoirs of material out of which planets may form. Around mature stars, they indicate that planetesimal formation has taken place, and around white dwarfs, they indicate that planetary material survived the whole of stellar evolution. Such a disc can manifest itself in various ways.

In planetary science a streaming instability is a hypothetical mechanism for the formation of planetesimals in which the drag felt by solid particles orbiting in a gas disk leads to their spontaneous concentration into clumps which can gravitationally collapse. Small initial clumps increase the orbital velocity of the gas, slowing radial drift locally, leading to their growth as they are joined by faster drifting isolated particles. Massive filaments form that reach densities sufficient for the gravitational collapse into planetesimals the size of large asteroids, bypassing a number of barriers to the traditional formation mechanisms. The formation of streaming instabilities requires solids that are moderately coupled to the gas and a local solid to gas ratio of one or greater. The growth of solids large enough to become moderately coupled to the gas is more likely outside the ice line and in regions with limited turbulence. An initial concentration of solids with respect to the gas is necessary to suppress turbulence sufficiently to allow the solid to gas ratio to reach greater than one at the mid-plane. A wide variety of mechanisms to selectively remove gas or to concentrate solids have been proposed. In the inner Solar System the formation of streaming instabilities requires a greater initial concentration of solids or the growth of solid beyond the size of chondrules.

<span class="mw-page-title-main">GG Tauri</span> Star in the constellation Taurus

GG Tauri, often abbreviated as GG Tau, is a quintuple star system in the constellation Taurus. At a distance of about 450 light years away, it is located within the Taurus-Auriga Star Forming Region. The system comprises three stars orbiting each other in a hierarchical triple system, known as GG Tauri A, and another binary star system more distant from the central system, known as GG Tauri B.

<span class="mw-page-title-main">PDS 70</span> T Tauri-type star in the constellation Centaurus

PDS 70 is a very young T Tauri star in the constellation Centaurus. Located 370 light-years from Earth, it has a mass of 0.76 M☉ and is approximately 5.4 million years old. The star has a protoplanetary disk containing two nascent exoplanets, named PDS 70b and PDS 70c, which have been directly imaged by the European Southern Observatory's Very Large Telescope. PDS 70b was the first confirmed protoplanet to be directly imaged.

<span class="mw-page-title-main">CI Tauri</span> Star in the constellation Taurus

CI Tauri is a young star, about 2 million years old, located approximately 523 light-years away in the constellation Taurus. It is still accreting material from a debris disk at an unsteady pace, possibly modulated by the eccentric orbital motion of an inner planet. The spectral signatures of compounds of sulfur were detected from the disk.

<span class="mw-page-title-main">Circumplanetary disk</span> Accumulation of matter around a planet

A circumplanetary disk is a torus, pancake or ring-shaped accumulation of matter composed of gas, dust, planetesimals, asteroids or collision fragments in orbit around a planet. They are reservoirs of material out of which moons may form. Such a disk can manifest itself in various ways.

<span class="mw-page-title-main">RW Aurigae</span> Young binary star system in the constellation Auriga

RW Aurigae is a young binary system in the constellation of Auriga about 530 light years away, belonging to the Taurus-Auriga association of the Taurus Molecular Cloud. RW Aurigae B was discovered in 1944.

James E. Owen is an astrophysicist at Imperial College London who studies exoplanets and accretion disks.

References

  1. 1 2 3 4 5 6 Glynn, Thomas (2017). "2017 Eddington Medal in Astronomy". www.staff.admin.cam.ac.uk. Retrieved 2018-10-19.
  2. 1 2 3 Clarke, Catherine Jane (1987). Accretion disc structure in binary star and galactic potentials. copac.jisc.ac.uk (DPhil thesis). University of Oxford. OCLC   499843339. EThOS   uk.bl.ethos.376904.
  3. ↑ Anon. "Fellows of Clare College, Cambridge". www.clare.cam.ac.uk. Archived from the original on 2020-08-08. Retrieved 2018-10-19.
  4. ↑ "People at the Institute". 24 January 2023.
  5. ↑ Stamatellos, Dimitris; Goodwin, Simon; Ward-Thompson, Derek (2014). The Labyrinth of Star Formation. Springer Science & Business Media. doi:10.1007/978-3-319-03041-8. ISBN   9783319030418.
  6. ↑ "Hydrodynamical simulations of protoplanetary discs in the era of ALMA imaging | Projects | FP7-IDEAS-ERC | CORDIS | European Commission". CORDIS | European Commission. Retrieved 2018-10-19.
  7. ↑ Starkey, Isabel (2016-03-02). "All Prize Winners". www.cctl.cam.ac.uk. Archived from the original on 2019-04-11. Retrieved 2018-10-19.
  8. 1 2 3 Clarke, Cathie (2014). Principles of Astrophysical Fluid Dynamics. Cambridge: Cambridge University Press. doi:10.1017/CBO9780511813450. ISBN   9781107666917. OCLC   892455461.
  9. ↑ J., Clarke, Cathie (2015-09-11). Dynamics of young star clusters and associations : Saas-Fee advanced course 42. Mathieu, Robert D.,, Reid, I. Neill,, Schweizerische Gesellschaft für Astrophysik und Astronomie. Heidelberg. ISBN   9783662472903. OCLC   921176157.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: multiple names: authors list (link)
  10. ↑ Haworth, Thomas J.; Facchini, Stefano; Clarke, Cathie J.; Cleeves, L. Ilsedore (2017). "First evidence of external disc photoevaporation in a low mass star forming region: the case of IM Lup". Monthly Notices of the Royal Astronomical Society: Letters. 468 (1): L108–L112. arXiv: 1703.03409 . Bibcode:2017MNRAS.468L.108H. doi: 10.1093/mnrasl/slx037 . ISSN   1745-3925. S2CID   56215417.
  11. ↑ "Giant planets around young star raise questions about how planets form". University of Cambridge. 2018-10-15. Retrieved 2018-10-19.
  12. 1 2 3 Clarke, C. J.; Tazzari, M.; Juhasz, A.; Rosotti, G.; Booth, R.; Facchini, S.; Ilee, J. D.; Johns-Krull, C. M.; M. Kama (2018). "High-resolution Millimeter Imaging of the CI Tau Protoplanetary Disk: A Massive Ensemble of Protoplanets from 0.1 to 100 au". The Astrophysical Journal Letters. 866 (1): L6. arXiv: 1809.08147 . Bibcode:2018ApJ...866L...6C. doi: 10.3847/2041-8213/aae36b . ISSN   2041-8205. S2CID   119042020.
  13. ↑ "Talks, Colloquia". www.physik.uni-heidelberg.de. Retrieved 2018-10-19.
  14. ↑ Haworth, Thomas J; Facchini, Stefano; Clarke, Cathie J; Mohanty, Subhanjoy (2018). "Where can a Trappist-1 planetary system be produced?". Monthly Notices of the Royal Astronomical Society. 475 (4): 5460–5473. arXiv: 1801.05822 . Bibcode:2018MNRAS.475.5460H. doi: 10.1093/mnras/sty168 . ISSN   0035-8711. S2CID   119460112.
  15. ↑ "Cathie Clarke". www.journals.elsevier.com. Retrieved 2018-10-19.
  16. ↑ "Cathie Clarke". royalsociety.org. Retrieved 2023-05-24.
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