Jay
M. Pasachoff specializes in studying the sun at total solar eclipses. With his colleagues and students, he carries out
observations to study the million-degree-temperature of the solar corona in
order to find out how the corona gets so hot and to study coronal structur3 and
dynamics. Their work has been principally supported by the National
Geographic Society, the National Science Foundation’s Solar Terrestrial Program
of the Atmospheric and Geospace Sciences Division, and the Keck Northeast
Astronomy Consortium.
See
http://www.solarcorona.com (or the former, archived
website at http://www.williams.edu/astronomy/eclipse)
for images and discussions of his 70 previous eclipse expeditions (as of early
2019), and of the student participation in it.
As Chair of the
International Astronomical Union's Working Group on Solar Eclipses, Pasachoff
supervises the group’s website at http://www.eclipses.info.
Drs.
Pasachoff, Souza, and Babcock and their students worked closely with the late
James Elliot and with Michael Person and Amanda Bosh of MIT and Amanda Sickafoose
of the South African Astronomical Observatory and MIT on occultations of stars
by objects in the outer solar system. Their 2002 observations of an occultation
of a star by Pluto showed that Pluto's atmosphere is undergoing global warming.
Their 2005 observations of a rare occultation of a star by Pluto's moon Charon
improved measurements of Charon's diameter and density and set new limits on
Charon's atmosphere. They have continued monitoring Pluto's atmosphere, which
has leveled off its temperature variation, most recently with observations from
two weeks before NASA’s New Horizon flyby of Pluto on July 14, 2015. Their work was supported by a grant
from NASA, and they use electronic cameras purchased on a previous NASA grant.
Pasachoff
participated, with Muzhou Lu ’13 (who is working for SpaceX as of 2019), on a
NASA-sponsored expedition to Argentina in 2017 to try to pin down the position
of 2014 MU69, since nicknamed Ultima Thule, a small object a billion
miles beyond Pluto. New Horizons
successfully flew by only 2,200 miles from its surface on January 1, 2019,
guided by that and subsequent occultation observations.
Pasachoff
and students observed the solar chromosphere, the middle layer of the solar
atmosphere, in high resolution using simultaneously the 1-m Swedish Solar
Telescope on La Palma in the Canary Islands and NASA's Transition Region and
Coronal Explorer (TRACE) spacecraft. They worked in collaboration with Drs.
Leon Golub and Ed DeLuca of the Harvard-Smithsonian Center for Astrophysics and
with scientists from the Lockheed Martin Solar and Astrophysics Laboratory. Their work was supported by a research grant
from NASA in the Guest Investigator Program for TRACE.
Owen
Westbrook '06 and Jennifer Yee (Keck Northeast Astronomy Consortium Summer
Fellow, Swarthmore '07) worked with Pasachoff in Williamstown and at the Roque
de los Muchachos Observatory on La Palma. Westbrook continued the project
as his senior thesis. They continued work that involved the senior thesis
of Kamen Kozarev '05 and earlier La Palma observations made with David Butts
'06 and Joseph Gangestad '06.
The
results of the Canary Islands spicule studies, related to studies from NASA's
Transition Region and Coronal Spacecraft, were included in the senior thesis of
Will Jacobson '08, and appeared in print, jointly with Alphonse Sterling of
NASA, as:
Pasachoff, Jay M., William A. Jacobson, and Alphonse C. Sterling, 2009,
"Limb Spicules from the Ground and from Space," Solar Phys., 260, #1,
59-82. arXiv astro-ph 0909.0027; DOI 10.1007/s11207-009-9430-x http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s11207-009-9430-x
Pasachoff
is included in a proposal to make high-resolution observations of spicules with
the Daniel K. Inouye Solar Telescope when it opens on Haleakala, Hawaii.
Pasachoff
has been investigating transits of Mercury and Venus, using ground-based
observations and observations from a variety of solar spacecraft. His
work has been in collaboration with Glenn Schneider of the Steward Observatory,
University of Arizona. Their analysis of a transit of Mercury across the
face of the sun led to an explanation of the long-questioned black-drop effect.
They applied their analysis to the observations from a NASA spacecraft and from
the Williams College Transit of Venus Expeditions to Thessaloniki, Greece, on
June 8, 2004 (the first transit of Venus visible since the year 1882, and
therefore much anticipated) and in 2012 from Haleakala, Hawaii. See the
special Williams website at http://www.transitofvenus.info for information about current and past transits. Pasachoff
and Suranjit Tilakawardane '07 observed the transit of Mercury in November 2006
from Haleakala, Maui, Hawaii. Bryce Babcock, working also with Kevin Reardon
'92, who is then at the Arcetri Observatory in Italy and is now at the U.S.
National Solar Observatory in Boulder, Colorado. They used one of our electronic cameras to
observe the transit of Mercury from the Sacramento Peak Observatory of the
National Solar Observatory, Sunspot, New Mexico. Reardon has since used a camera he helped
develop to observe from the Sacramento Peak Observatory for the 2016 transit
and potentially the 2019 transit.
The
2004 Williams College Transit of Venus Expedition included Pasachoff, Babcock,
David Butts '06, Joseph Gangestad '06, Owen Westbrook '06, Alan Cordova '06,
Kayla Gaydosh (Keck Northeast Astronomy Consortium Summer Fellow, Bryn Mawr
'05), and Rob Wittenmyer '98. They worked in Greece in collaboration with
Prof. John Seiradakis of the Aristotelian University of Thessaloniki. Dr.
Steven Souza observed the transit from Williamstown. The 2012 Williams College Transit of Venus
expedition team at Haleakala included Jay Pasachoff, Glenn Schneider, Bryce
Babcock, Muzhou Lu ’13, Ron Dantowitz, Aram Friedman, Rob Lucas, Eric Pilger
’82, Naomi Pasachoff, Helen Robinson, Claudia Pilger, Raisha Friedman, and
Helen Robinson. We were represented at Sacramento Peak by Kevin Reardon ’92. We
were assisted with data processing in Williamstown by Eric Edelman ’13.
The
Williams College Transit of Venus Expeditions of 2004 and 2012 were supported
by grants from the Committee for Research and Exploration of the National
Geographic Society.
For
the 2004 transit, Pasachoff and Schneider also worked with Dr. Richard Willson
of Columbia University with observations of the total solar irradiance as
observed from Willson's ACRIMsat, a spacecraft that measures what used to be
called the solar constant. For the 2012 transit, they worked with Greg
Kopp of the University of Colorado at Boulder, and have a joint paper pending
on the Total Solar Irradiance measurements from space satellites. Their observations of Venus's effect on the
Total Solar Irradiance has applications to transit observations of the many newly
discovered exoplanets, planets orbiting other stars, that have been discovered
with the transit technique.
Pasachoff
and his students worked with Drs. Nancy Evans and Scott Wolk of the
Harvard-Smithsonian Center for Astrophysics on studying x-ray observations of
galactic star clusters made with the Chandra X-ray Observatory. The
observations began with the double cluster h and chi Persei. The work was supported by a grant from
NASA through the Smithsonian Astrophysical Observatory.
Megan
Bruck '07 worked on the project in Williamstown and Cambridge and continued her
summer work as an Independent Study course. She worked after graduation as a
research assistant in x-ray astronomy at the Harvard-Smithsonian Center for
Astrophysics, got her Ph.D. in planetary sciences at Brown University, and is
on the staff working on planetary defense (killer asteroids) at Lawrence
Livermore National Laboratory.
Pasachoff
also studies cosmic deuterium and its relation to cosmology. Theory shows that
all the deuterium (heavy hydrogen) in the Universe was formed in the first 3
minutes after the big bang; studies of the current distribution of deuterium in
our Milky Way Galaxy can lead to an evaluation of the density of matter in the
Universe and thus whether the Universe has enough gravity to eventually cease
its expansion. Pasachoff and students, along with colleague Donald Lubowich of
the American Institute of Physics, have used telescopes at the Kitt Peak
National Observatory and the National Radio Astronomy Observatory to study
deuterium in galactic stars and in the Sagittarius A radio source at the center
of our galaxy. They have also obtained observations in the direction of
the star iota Herculis and of the Orion Nebula at the Kitt Peak National
Observatory. They worked with Prof. Tom Millar of the University of Manchester
on explaining various deuterium molecular observations with chemical
interstellar models.
Terry-Ann
Suer '05 worked on various stages of the project and set up a Web page with
historical papers at http://www.cosmicdeuterium.info. Dr. Suer received her
Ph.D. on high-pressure diamond-anvil measurements at the University of Paris
and as of 2018-19 is a postdoctoral fellow in the geosciences department at
Harvard University.
Prof.
Pasachoff works with Prof. Roberta J. M. Olson of the New-York Historical
Society, Professor Emerita of Art History at Wheaton College, to study the
relation of art and astronomy. They began with a study of images of comets
in 18th and 19th century British art and the growth of scientific accuracy in
artistic representation. On twin grants from the Getty Foundation, as Getty
Fellows they wrote a book about the subject, which involved research in London,
Cambridge, and Edinburgh at the Royal Society, the Royal Astronomical Society,
the Royal Observatories in Greenwich, Edinburgh, and Cambridge, the British
Museum, the Tate Collection, and elsewhere. The book was published as Olson and
Pasachoff: Fire in the Sky: Comets and Meteors,
the Decisive Centuries, in British Art and Science (Cambridge University Press,
hardback 1998; paperback, 1999). Students participated in a Winter Study
course in England recreating many of the research sites.
Pasachoff
and Olson gave an invited paper about comets in science and art in early
Renaissance Italy at the meeting of the Division of Planetary Sciences of the
American Astronomical Society in Padua, Italy. They subsequently gave a
paper about astronomy in the Medician Court at a meeting of the College Art
Association in Seattle.
Pasachoff
and Olson studied a painting in a Bavarian abbey showing St. Benedict viewing a
total solar eclipse. See 2007, "St. Benedict Sees the Light: Asam's Solar
Eclipses as a Metaphor," Religion and the Arts 11, 299-329.
(www.brill.nl/rart). Also http://apod.nasa.gov/apod/ap080128.html.
They
subsequently discussed comets in art at a European Space Agency comet workshop
in Brussels.
Pasachoff
and Olson gave a paper about solar eclipses in art history at the 6th meeting
on The Inspiration of Astronomical Phenomena held in Venice, Italy, in 2009.
They gave a paper about Caroline Herschel, and the eight or more comets she
discovered during the 1790's, at the 7th meeting on The Inspiration of
Astronomical Phenomena held in Bath, England, in 2010. www.insap.org.
Their
joint magnum opus, Cosmos: The Art and
Science of the Universe, is being published in 2019 by Reaktion Books
(London), with U.S. distribution from U. Chicago Press.