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Astronomical Observatory: Publications

Publications of the Calvin College Observatory

Rehoboth domeThe central mission of the Calvin College Observatory is educational, and the telescopes are used by students at all levels from first year non-science majors to fourth year physics majors. However, an excellent way to learn about science is to do science—to discover something new. Therefore, the laboratory portion of most Calvin astronomy classes contains some "new science" project. Dedicated telescopes of modest aperture are especially well suited to contribute to the study of objects that vary in position or brightness with time.

Part of doing science is to submit the results to a refereed journal to make them known to the larger scientific community. The purpose of this web page is to document those publications based on observations made with the Calvin telescopes. Additional astronomy publications by Calvin staff and students may be found in the Physics and Astronomy Department publications page.

Variable Stars

"A New Dynamical Class of High Period Derivative Contact Binaries", Lawrence Molnar, Michaela Blain, Evan Cook, Sarah Whitten, and Henry Kobulnicky, (Presentation at the 233rd Meeting of the American Astronomical Society, 2019 January 10) [Eposter] Coauthors include Calvin Professor Lawrence Molnar and Calvin students Michaela G. Blain, Evan M. Cook, and Sarah M. Whitten.

"The First Post-Kepler Brightness Dips of KIC 8462852", Tabetha S. Boyajian and many coauthors, (Astrophysical Journal Letters, 853:L8, 2018 January 20) [ApJ] [Full text of arXiv]. Coauthors include Calvin Professor Lawrence Molnar and Calvin students Michaela G. Blain, Evan M. Cook, and Kenton A. Greene.

The Kepler satellite showed mysterious dips in brightness from this star on several occasions over its four-year survey. In this paper we show for the first time that the dips are wavelength-dependent: more blue light is lost than red. This result is consistent with dust along the line of sight (the origin of which remains a mystery) but rules out solid objects (such as alien megastructures, which would show wavelength independent dimming). This conclusion was long awaited and received wide media attention. Examples include The Washington Post, Sky and Telescope, and National Geographic.

"Prediction of a red nova outburst in KIC 9832227", Lawrence A. Molnar, Daniel M. Van Noord, Karen Kinemuchi, Jason P. Smolinski, Cara E. Alexander, Evan M. Cook, Byoungchan Jang, Henry A. Kobulnicky, Christopher J. Spedden, Steven D. Steenwyk, Astrophysical Journal (840:1 2017 May 1) [ApJ] [Full text on arXiv]

Asteroid Discovery

Each Fall and Spring, students in the Astronomy 110 and 111 classes have a single lab in which they hunt for new asteroids. Each Spring, students in the Physics 134 class have an extended set of labs in which they seek to discover and follow the orbits of new asteroids. Follow-up is necessary in order to determine the orbital parameters precisely enough for the asteroids to have permanent numbers assigned by the Minor Planet Center. This requires observations over at least four oppositions. All Calvin observations are submitted to the Minor Planet Center for inclusion in their publications and central data base. These data are used by solar system dynamicists seeking to reconstruct the history of the asteroid belt in particular and the planets with which they interact.

As a result of submission of thousands of measurements since 2003:

  • 181 asteroids have received permanent designations crediting the Calvin observatory as the discovery site.

See the full list of asteroid discoveries for more details.

Asteroid Rotation

"Efficient spin sense determination of Flora-region asteroids via the epoch method", Melissa J. Dykhuis, Lawrence A. Molnar, Christopher J. Gates, Joshua A. Gonzales, Jared J. Huffman, Aaron R. Maat, Stacy L. Maat, Matthew I. Marks, Alyssa R. Massey-Plantinga, Nathan D. McReynolds, Jeremy A. Schut, Joshua P. Stoep, Andrew J. Stutzman, Brandon C. Thomas, George W. Vander Tuig, Jess W. Vriesema, and Richard Greenberg, Icarus, vol. 267, pp. 174-203 (January 2016).

[NOTE: All authors except the last one are student coauthors working with Prof. L. Molnar.]

"New Constraints on the Asteroid 298 Baptistina, the Alleged Family Member of the K/T Impactor", Daniel J. Majaess, David Higgins, Larry A. Molnar, Melissa J. Haegert, David J. Lane, David G. Turner, and Inga Nielsen, Journal of the Royal Astronomical Society of Canada, volume 103, pages 7-10 (February, 2009).

[NOTE: The rotation rate of this particular asteroid is of special interest because of the connection that has been suggested between it and the asteroid that struck the Earth at the time of the K/T boundary. This paper is reflects an international collaboration (and observatories over a range of longitudes), which is especially valuable for longer period objects (16.23 hours in this case). The Calvin measurements were made by Prof. Molnar and student Melissa Haegert as part of a broader study of the dynamics of asteroids in this region of the asteroid belt (see the next entry for more on that).]

"The Yarkovsky Effect in the Flora and Baptistina Asteroid Families", Lawrence A. Molnar & Melissa J. Haegert, 2008, Bulletin of the American Astronomical Society, Volume 40, p. 286. (An oral presentation made at the 39th meeting of the Division for Dynamical Astronomy of the American Astronomical Society in Boulder, Colorado, 2008 April 28.)

"Lightcurve Analysis of an Unbiased Sample of Trojan Asteroids", Lawrence A. Molnar, Melissa J. Haegert, and Kathleen M. Hoogeboom, The Minor Planet Bulletin, volume 35, pages 82-84 (2008 April).

[NOTE: The observations reported in this paper were taken in part by Calvin student Kathy Hoogeboom for an upper level research course, Astronomy 395, and in part by student Melissa Haegert as part of a summer research project.]

"Lightcurve Analysis of a Magnitude Limited Asteroid Sample", Lawrence A. Molnar, Melissa J. Haegert, Christopher N. Beaumont, Marjorie J. Block, Timothy H. Brom, Andrew R. Butler, Peter L. Cook, Allyson G. Green, Joshua P. Holtrop, Kathleen M. Hoogeboom, Jason J. Kulisek, Jonathan S. Lovelace, Jeffery S. Olivero, Achyut Shrestha, Jessie F. Taylor, Kenneth D. Todd, John D. Vander Heide, and Samuel O. Van Scoter, The Minor Planet Bulletin, volume 35, pages 9-12 (2008 January).

[NOTE: The observations reported in this paper were taken for and analyzed by the Spring 2006 Astronomy 211 class. The students in that class are all coauthors on the newly published paper.]:

"Lightcurve analysis of five main belt asteroids at the Calvin-Rehoboth Observatory", Lawrence A. Molnar and Melissa J. Haegert, The Minor Planet Bulletin, volume 34, pages 126-128 (2007 October).

[NOTE: The observations reported in this paper were taken in part as a planning exercise for the Spring 2006 Astronomy 211 project. Final analysis was done by Calvin student Melissa Haegert as part of a summer research project.]


"Calvin-Rehoboth Robotic Twin Telescopes" Haarsma, D. B., Molnar, L. A., and Van Baak, D. A. Bulletin of the American Astronomical Society, volume 36, p. 1499 (2004 December).

[NOTE: See a powerpoint copy of the poster presentation made at the January 2005 American Astronomical Society meeting.]

Pluto Occultation

"Pluto's lower atmosphere and pressure evolution from ground-based stellar occultations, 1988-2016" Meza, E. Sicardy, B., (and many others, including L. Molnar). Astronomy and Astrophysics (accepted for publication March 1, 2019).

[NOTE: Calvin College observed occultations by Pluto of background stars on 2007 March 18 (from New Mexico) and 2008 August 25 (from Grand Rapids, Michigan). This paper combines a large number of Pluto occultation measurements to explore the properties of Pluto's tenuous atmosphere. It shows large seasonal increases in atmospheric pressure occurring over the time range observed.]

"Pluto's Atmospheric Activity, Ephemeris Offset and Satellite Detections from Observations in 2007" Sicardy, B., Widemann, T., Colas, F., Doressoundiram, A., Lecacheux, J., Vacier, F., Beisker, W., Assafin, M., Camargo, J., da Silva Neto, D., Ribas, F. B., Andrei, A., Vieira Martins, R., Behrend, R., Hubbard, W., Larson, S., Marchis, F., Wong, M. H., Severson, S., Dunham, D., Warner, B. D., Peterson, C., Molnar, L. A., George, T., Maley, P., Coziol, R., Choi, Y., ESO team, Bath, K., and Kretlow, M. Bulletin of the American Astronomical Society, volume 39, No. 3, pp. 540-541 (2007 October).

[NOTE: Calvin College contributed a lightcurve of the 18 March 2007 occultation of a 15th magnitude star to this presentation to the 39th meeting of the Division for Planetary Sciences. Our northwest New Mexico observing site was forecast to be near the center of the occultation event. The resulting lightcurve, combined with lightcurves from other sites, is being used to significantly revise the orbit of Pluto as well as to explore the properties of its tenuous atmosphere.]

This page updated March 7, 2019.


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