My CV (Last updated July 2007)

ADS First-Author Publications
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My Homegrown IDL Routines, where kludges add in quadrature

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Selected Publications

  • A New Planet Around an M Dwarf: Revealing a Correlation Between Exoplanets and Stellar Mass John Asher Johnson, R. Paul Butler, Geoffrey W. Marcy, Debra A. Fischer, Steven S. Vogt, Jason T. Wright, Kathryn M. G. Peek, 2007, ApJ Accepted (astro-ph/0707.2409)
  • Retired A Stars and Their Companions: Exoplanets Orbiting Three Intermediate-Mass Subgiants John Asher Johnson, Debra A. Fischer, Geoffrey W. Marcy, Jason T. Wright, Peter Driscoll, R. Paul Butler, Saskia Hekker, Sabine Reffert, 2007, ApJ, 665, 785 (astro-ph/0704.2455)
  • A Long-Period Jupiter-Mass Planet Orbiting the Nearby M Dwarf GJ 849 R. Paul Butler, John Asher Johnson, Geoffrey W. Marcy, Jason T. Wright, Steven S. Vogt, Debra A. Fischer, PASP, 118, 1685
  • An Eccentric Hot Jupiter Orbiting the Subgiant HD 185269 John Asher Johnson, Geoffrey W. Marcy, Debra A. Fischer, Gregory W. Henry, Jason T. Wright, Howard Isaacson, Chris McCarthy, 2006, ApJ, 652, 1724
  • The N2K Consortium VI: Doppler Shifts Without Templates and Three New Short-Period Planets John Asher Johnson, Geoffrey W. Marcy, Debra A. Fischer, Gregory Laughlin, R. Paul Butler, Gregory W. Henry, Jeff A. Valenti, Eric B. Ford, Steven S. Vogt, Jason T. Wright, 2006, ApJ, 647, 600
  • Measurement of the Spin-Orbit Alignment of the Exoplanetary System HD 189733 Josh Winn, John Asher Johnson, Geoff Marcy, R. Paul Butler, Steve Vogt, Greg Henry, A. Roussanova, Matt Holman, et al., 2006, ApJL, in press (astro-ph/0609506)
  • The N2K Consortium. II. A Transiting Hot Saturn around HD 149026 with a Large Dense Core Sato, Bun'ei; Fischer, Debra A.; Henry, Gregory W.; Laughlin, Greg; Butler, R. Paul; Marcy, Geoffrey W.; Vogt, Steven S.; Bodenheimer, Peter; Ida, Shigeru; Toyota, Eri; Wolf, Aaron; Valenti, Jeff A.; Boyd, Louis J.; Johnson, John A.; Wright, Jason T.; Ammons, Mark; Robinson, Sarah; Strader, Jay; McCarthy, Chris; Tah, K. L.; Minniti, Dante (2005 ApJ)
  • Measurement of Spin-Orbit Alignment in an Extrasolar Planetary System Joshua Winn, Robert Noyes, Matthew Holman, David Charbonneau, Yasuhiro Ohta, Atsushi Taruya, Yasushi Suto, Norio Narita, Edwin Turner, John Johnson, Geoffrey Marcy, Paul Butler, Steven Vogt (2005 ApJ)
  • The History of the Mysterious Eclipses of KH 15D II. Asiago, Kiso, Kitt Peak, Mt. Wilson, Palomar, Tautenburg and Rozhen Observatories, 1954-97 John Johnson, Joshua Winn, Francesca Rampazzi, Cesare Barbieri, Hiroyuki Mito, Ken-ichi Tarusawa, Milcho Tsvetkov, Ana Borisova, Helmut Meusinger (2005 AJ)
  • Five New Extrasolar Planets Geoffrey Marcy, R. Paul Butler, Stephen Vogt, Debra Fischer, Gregory Henry, Greg Laughlin, Jason Wright, John Johnson (2005 ApJ)
  • KH 15D: A Spectroscopic Binary John Johnson, Geoffrey Marcy, Catrina Hamilton, William Herbst, Christopher Johns-Krull (2004 AJ)
  • KH 15D: Gradual Occultation of a Pre-Main-Sequence Binary Joshua Winn, Matthew Holman, John Johnson, Krzysztof Stanek, Peter Garnavich (2004 ApJ)
  • The History of the Mysterious Eclipses of KH 15D: Asiago Observatory, 1967-1982 John Johnson & Joshua Winn (2004 AJ)

    Research Interests

    (Last updated May 2007)

    Current Projects

    head in hole Subgiants:
    I currently work for Geoff Marcy and the California & Carnegie Planet Search. My thesis project involves searching for planets around stars more massive than ~1.3 solar by monitoring the radial velocities of a sample of ~150 subgiants. Subgiants are cooler and rotate slower than their main-sequence progenitors. G- and K-type subgiants therefore have more and narrower lines than A- and F-type main-sequence stars of the same mass, which may make them ideal planet search targets among higher-mass stars.

    Here are some cool articles about my work:

    Planets of Massive, Retired A Stars (Sky & Telescope)
    Heftier Stars More Likely To Host Planets (New Scientist)

    Other Projects

    I have also worked on the spectroscopic analysis of the eclising pre-main-sequence star KH 15D in collaboration with Bill Herbst from Weslyan University and Josh Winn at Harvard CfA. KH 15D is a sun-like star in the young (~3 Myr old) star forming region NGC 2264 which is about 2200 light years away. This star is an extremely intriguing object because it undergoes deep, 3.5 magnitude eclipses every 48 days which last 24 days with a very steep ingress and egress. No object quite like this has ever been observed. Here is a light curve obtained at the Van Vleck observatory.

    The leading theory is that KH 15D is a pre-main-sequence binary system with an inclined, nodally precessing, circumbinary disk (see Winn et al., Chiang & Murray-Clay). This theory was inspired by the historical light curve derived from the analysis of archival photographic plates (Johnson & Winn 2004 and Johnson et al. 2005) and the spectroscopic evidence of a stellar-mass binary companion (Johnson et al. 2004) .