Comet science: Rosetta and beyond
Lead Research Organisation:
The Open University
Department Name: Faculty of Sci, Tech, Eng & Maths (STEM)
Abstract
Comets have fascinated, and terrified, people throughout recorded history. The unpredictable appearances of bright comets, even in times when the motions of the "wandering stars" (planets) were well understood, meant that they were treated with suspicion. Today, our knowledge of comets has come a long way, but there are still many puzzles left to solve. As I write this, telescopes and spacecraft scattered all over the solar system are tracking comet ISON as it plunges toward the Sun, but we still cannot predict whether it will light up the sky as a "Great comet" or fizzle out before it arrives.
Nowadays we are interested in comets not as harbingers of doom, but because we can use them to learn about the disc of rock and ice that formed the planets. Comets and asteroids are the leftover "building blocks" from the early days of the solar system; the survivors that didn't get incorporated into one of the planets, crash into the Sun, or get thrown out of the system altogether.
The next few years will be an exciting time in cometary science, as the ESA mission "Rosetta" will be exploring comet 67P/Churyumov-Gerasimenko in great detail. This audacious mission will, for the first time ever, rendezvous with a comet and follow it on its orbit around the Sun. Its array of scientific instruments will watch as the activity of the comet evolves. This mission will not only get closer to a comet than any previous spacecraft (down to only a few km from the surface, flying deep within jets of gas and dust), and be the first to spend an extended period of time watching changes on the comet; it will also land a probe on the surface, to find out exactly what the comet is made of.
I will work on the data that will be returned by Rosetta, especially through the camera system OSIRIS, and also by parallel ground-based observations of the comet. Such ground-based context observations are of critical importance: While the spacecraft will return very detailed information about the nucleus and inner coma of one particular comet, we need to be able to see how these details correspond to the large-scale activity that can be observed with telescopes in order to relate this to comets in general. I am coordinating a campaign of observations from telescopes worldwide. This will include a significant contribution from amateur astronomers, and from UK schools via the Faulkes Telescope project, when the comet is bright enough. Together, these data will reveal how cometary activity works.
In addition to 67P, I will also observe other comets for comparison. These will include those of the same class, the short-period "Jupiter family" comets, and also other types such as main belt and long-period comets, including comet ISON. The interaction between the Sun and comets like ISON, which get very close to the solar surface, not only tells us about how highly active comets behave under extreme heating conditions, but can also reveal new information about the Sun itself and the environment around it. Main belt comets are at the other end of the cometary activity scale: They are a recently discovered missing link between icy comets and rocky asteroids, with asteroid-like orbits but weak comet-like activity. They are also a potential source of Earth's water: It is much easier to have delivered water from the outer asteroid belt to the early Earth than it is to account for all of it from the impact of "normal" comets.
My work will look at the differences in the activity of the three classes of comet (high-activity near-Sun comets, medium-activity Jupiter family comets, and low-activity main belt comets), and the question of whether the variation is due to the different source regions they come from, or due to the environment in which they are active now. This "nature vs. nurture" question for comets will provide clues about the properties of different areas of the planet-forming disc, and the evolution of icy bodies over the age of the solar system.
Nowadays we are interested in comets not as harbingers of doom, but because we can use them to learn about the disc of rock and ice that formed the planets. Comets and asteroids are the leftover "building blocks" from the early days of the solar system; the survivors that didn't get incorporated into one of the planets, crash into the Sun, or get thrown out of the system altogether.
The next few years will be an exciting time in cometary science, as the ESA mission "Rosetta" will be exploring comet 67P/Churyumov-Gerasimenko in great detail. This audacious mission will, for the first time ever, rendezvous with a comet and follow it on its orbit around the Sun. Its array of scientific instruments will watch as the activity of the comet evolves. This mission will not only get closer to a comet than any previous spacecraft (down to only a few km from the surface, flying deep within jets of gas and dust), and be the first to spend an extended period of time watching changes on the comet; it will also land a probe on the surface, to find out exactly what the comet is made of.
I will work on the data that will be returned by Rosetta, especially through the camera system OSIRIS, and also by parallel ground-based observations of the comet. Such ground-based context observations are of critical importance: While the spacecraft will return very detailed information about the nucleus and inner coma of one particular comet, we need to be able to see how these details correspond to the large-scale activity that can be observed with telescopes in order to relate this to comets in general. I am coordinating a campaign of observations from telescopes worldwide. This will include a significant contribution from amateur astronomers, and from UK schools via the Faulkes Telescope project, when the comet is bright enough. Together, these data will reveal how cometary activity works.
In addition to 67P, I will also observe other comets for comparison. These will include those of the same class, the short-period "Jupiter family" comets, and also other types such as main belt and long-period comets, including comet ISON. The interaction between the Sun and comets like ISON, which get very close to the solar surface, not only tells us about how highly active comets behave under extreme heating conditions, but can also reveal new information about the Sun itself and the environment around it. Main belt comets are at the other end of the cometary activity scale: They are a recently discovered missing link between icy comets and rocky asteroids, with asteroid-like orbits but weak comet-like activity. They are also a potential source of Earth's water: It is much easier to have delivered water from the outer asteroid belt to the early Earth than it is to account for all of it from the impact of "normal" comets.
My work will look at the differences in the activity of the three classes of comet (high-activity near-Sun comets, medium-activity Jupiter family comets, and low-activity main belt comets), and the question of whether the variation is due to the different source regions they come from, or due to the environment in which they are active now. This "nature vs. nurture" question for comets will provide clues about the properties of different areas of the planet-forming disc, and the evolution of icy bodies over the age of the solar system.
Publications
A'Hearn M. F.
(2015)
Imaging the Gas from 67P/Churyumov-Gerasimenko
in 46th Annual Lunar and Planetary Science Conference
A'Hearn Michael F.
(2015)
Rotational Variation of Outgassing Morphology in 67P/Churyumov-Gerasimenko
in IAU General Assembly
Arellano Ferro A
(2016)
Erratum: A detailed census of variable stars in the globular cluster NGC 6333 (M9) from CCD differential photometry
in Monthly Notices of the Royal Astronomical Society
Bachelet E
(2018)
First Assessment of the Binary Lens OGLE-2015-BLG-0232
in The Astrophysical Journal
Bennett D
(2016)
THE FIRST CIRCUMBINARY PLANET FOUND BY MICROLENSING: OGLE-2007-BLG-349L(AB)c
in The Astronomical Journal
Bhattacharya A
(2016)
DISCOVERY OF A GAS GIANT PLANET IN MICROLENSING EVENT OGLE-2014-BLG-1760
in The Astronomical Journal
Blum J
(2017)
Evidence for the formation of comet 67P/Churyumov-Gerasimenko through gravitational collapse of a bound clump of pebbles
in Monthly Notices of the Royal Astronomical Society
Bodewits D
(2016)
CHANGES IN THE PHYSICAL ENVIRONMENT OF THE INNER COMA OF 67P/CHURYUMOV-GERASIMENKO WITH DECREASING HELIOCENTRIC DISTANCE
in The Astronomical Journal
Bowles N
(2018)
CASTAway: An asteroid main belt tour and survey
in Advances in Space Research
Bozza V
(2016)
SPITZER OBSERVATIONS OF OGLE-2015-BLG-1212 REVEAL A NEW PATH TOWARD BREAKING STRONG MICROLENS DEGENERACIES
in The Astrophysical Journal
Davidsson B
(2016)
The primordial nucleus of comet 67P/Churyumov-Gerasimenko
in Astronomy & Astrophysics
Davidsson Bjorn
(2015)
The primordial nucleus of Comet 67P/Churyumov-Gerasimenko
in AAS/Division for Planetary Sciences Meeting Abstracts #47
Deller J
(2015)
A new approach to modelling impacts on rubble pile asteroid simulants
in Monthly Notices of the Royal Astronomical Society
Dias-Oliveira A
(2015)
PLUTO's ATMOSPHERE FROM STELLAR OCCULTATIONS IN 2012 AND 2013
in The Astrophysical Journal
Dias-Oliveira Alex
(2015)
Pluto's atmosphere from stellar occultations in 2012 and 2013
in AAS/Division for Planetary Sciences Meeting Abstracts #47
Dominik M
(2019)
OGLE-2014-BLG-1186: gravitational microlensing providing evidence for a planet orbiting the foreground star or for a close binary source?
in Monthly Notices of the Royal Astronomical Society
Dominik Martin
(2015)
GravityCam: ground-based wide-field high-resolution imaging and high-speed photometry
in AAS/Division for Extreme Solar Systems Abstracts
Evans D
(2018)
High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP) II. Lucky Imaging results from 2015 and 2016
in Astronomy & Astrophysics
Evans D
(2016)
High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP) I. Lucky imaging observations of 101 systems in the southern hemisphere???
in Astronomy & Astrophysics
Fernandez Yanga R.
(2016)
The Distribution of Geometric Albedos of Jupiter-Family Comets From SEPPCoN and Visible-Wavelength Photometry
in American Astronomical Society Meeting Abstracts #227
Fernandez Yanga R.
(2015)
The Distribution of Geometric Albedos of Jupiter-Family Comets From SEPPCoN and Visible-Wavelength Photometry
in AAS/Division for Planetary Sciences Meeting Abstracts #47
Figuera Jaimes R
(2016)
Many new variable stars discovered in the core of the globular cluster NGC 6715 (M 54) with EMCCD observations
in Astronomy & Astrophysics
Figuera Jaimes R
(2016)
Exploring the crowded central region of ten Galactic globular clusters using EMCCDs Variable star searches and new discoveries???
in Astronomy & Astrophysics
Fitzsimmons A
(2017)
Spectroscopy and thermal modelling of the first interstellar object 1I/2017 U1 'Oumuamua
in Nature Astronomy
Fraser W
(2018)
The tumbling rotational state of 1I/'Oumuamua
in Nature Astronomy
Fulle M
(2019)
The refractory-to-ice mass ratio in comets
in Monthly Notices of the Royal Astronomical Society
Fulle M.
(2015)
Dust Measurements in the Coma of Comet 67P/Churyumov-Gerasimenko Inbound to the Sun Between 3.7 and 3.4 AU
in 46th Annual Lunar and Planetary Science Conference
Giannini E
(2016)
MiNDSTEp differential photometry of the gravitationally lensed quasars WFI 2033-4723 and HE 0047-1756: microlensing and a new time delay
in Astronomy & Astrophysics
Grün E
(2016)
The 2016 Feb 19 outburst of comet 67P/CG: an ESA Rosetta multi-instrument study
in Monthly Notices of the Royal Astronomical Society
Han C
(2016)
OGLE-2015-BLG-0479LA,B: BINARY GRAVITATIONAL MICROLENS CHARACTERIZED BY SIMULTANEOUS GROUND-BASED AND SPACE-BASED OBSERVATIONS
in The Astrophysical Journal
Han C
(2018)
OGLE-2017-BLG-0329L: A Microlensing Binary Characterized with Dramatically Enhanced Precision Using Data from Space-based Observations
in The Astrophysical Journal
Hansen K
(2016)
Evolution of water production of 67P/Churyumov-Gerasimenko: An empirical model and a multi-instrument study
in Monthly Notices of the Royal Astronomical Society
Henderson C
(2016)
Campaign 9 of the K2 Mission: Observational Parameters, Scientific Drivers, and Community Involvement for a Simultaneous Space- and Ground-based Microlensing Survey
in Publications of the Astronomical Society of the Pacific
Herique A
(2018)
Direct observations of asteroid interior and regolith structure: Science measurement requirements
in Advances in Space Research
Hines Dean C.
(2015)
Hubble Space Telescope Imaging Polarimetry of Comet 67P/Churyumov-Gerasimenko Obtained During the Rosetta Mission
in AAS/Division for Planetary Sciences Meeting Abstracts #47
Hsieh H
(2015)
SUBLIMATION-DRIVEN ACTIVITY IN MAIN-BELT COMET 313P/GIBBS
in The Astrophysical Journal
Hundertmark M
(2018)
RoboTAP: Target priorities for robotic microlensing observations
in Astronomy & Astrophysics
Hyland M
(2019)
Near-UV and optical spectroscopy of comets using the ISIS spectrograph on the WHT
in Monthly Notices of the Royal Astronomical Society
Jones G
(2017)
The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets
in Space Science Reviews
Jones G
(2018)
The proposed Caroline ESA M3 mission to a Main Belt Comet
in Advances in Space Research
Jørgensen U
(2018)
GravityCam: higher resolution visible wide-field imaging
Kains N
(2016)
Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry (Corrigendum)
in Astronomy & Astrophysics
Kains N
(2015)
A census of variability in globular cluster M 68 (NGC 4590)
in Astronomy & Astrophysics
Knight M
(2017)
Gemini and Lowell observations of 67P/Churyumov-Gerasimenko during the Rosetta mission
in Monthly Notices of the Royal Astronomical Society
Knight M
(2016)
COMET 322P/ SOHO 1: AN ASTEROID WITH THE SMALLEST PERIHELION DISTANCE?
in The Astrophysical Journal
Knight Matthew M.
(2015)
322P/SOHO 1: Sunskirting Comet or Asteroid?
in AAS/Division for Planetary Sciences Meeting Abstracts #47
Kokotanekova R
(2018)
Implications of the small spin changes measured for large Jupiter-family comet nuclei
in Monthly Notices of the Royal Astronomical Society
Kokotanekova R
(2017)
Rotation of cometary nuclei: new light curves and an update of the ensemble properties of Jupiter-family comets
in Monthly Notices of the Royal Astronomical Society
Koshimoto N
(2017)
MOA-2016-BLG-227Lb: A Massive Planet Characterized by Combining Light-curve Analysis and Keck AO Imaging
in The Astronomical Journal
Kwon Y
(2021)
VLT spectropolarimetry of comet 67P: dust environment around the end of its intense southern summer
in Astronomy & Astrophysics