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The accurate measurement of light (photometry)听from听astrophysical sources听enables us to investigate听different objects in the Universe, from planetary satellites, through extrasolar planets, to distant supernovae. [The plot above shows the change in brightness observed as听Triton, one of Neptune's moons, occults听(passes听in front of) a background star (data听recorded on 5 October 2017 by a team of staff and undergraduate students).]
- Exoplanet Transits
We have regularly observed the transits of听extrasolar planets using UCLO telescopes. From the light curves obtained, one can听constrain physical parameters of the exoplanet, such as the planet radius and tilt of its orbit.听
One of our early successes was the independent discovery of the transit of the unusual听exoplanet known as HD80606b, which moves in听a highly eccentric听orbit with period听111 days: observations were carried out through the night of Feb 13-14, 2009, by a team of staff and undergraduate students, and the resulting light curve provided important constraints on the nature of the exoplanet system. An illustration of the light curve is shown below.
Observations of the transits of other exoplanet systems have been made, often by final-year undergraduate project students who have investigated specific aspects of different exoplanet systems; many of our students who got their first experience of exoplanet science using UCLO observations听have progressed to doctoral听research programmes in exoplanet science, 澳门历史开奖记录 and elsewhere.
UCLO observations of exoplanet transits have been published听; and in the .
- Microlensing
We monitor the brightness variations exhibited by microlensing sources, where stars are seen to change brightness due to the amplification听of light by the gravitational field of听a听(generally,听unseen) foreground object; we have concentrated听in particular on those microlensing events听triggered by听the听. We contributed data for the monitoring of the听light curve of the unusual binary microlensing events known as Gaia16aye : the rapid fade in the source听brightness during a so-called `caustic crossing', as observed in UCLO images obtained on the Celestron 35-cm telescopes听by undergraduate students, is shown below.
- Supernovae
The nearby Type Ia supernova known as SN2014J in the galaxy Messier 82 was discovered during a routine undergraduate teaching session 澳门历史开奖记录O on January 21, 2014. The image shows a colour composite obtained on the night of 23-24 January (image credit: Prof. Ian Howarth), with the supernova indicated.
The supernova was discovered serendipitously听by Dr. Steve Fossey and a team of undergraduate students - Ben Cooke, Guy Pollack, Matt Wilde and Tom Wright - during an undergraduate training session on the C14 telescope. Steve's presentation of the story of the discovery, and its importance, are available in the听UCL Lunch Hour lecture that he gave in October 2014:
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