Browsing by Author "Irwin, Jonathan"

Now showing items 1-15 of 15

    • An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-Type M Dwarfs 

      West, Andrew A.; Weisenburger, Kolby L.; Irwin, Jonathan; Berta-Thompson, Zachory K.; Charbonneau, David; Dittmann, Jason Adam; Pineda, J. Sebastian (IOP Publishing, 2015)
      Using spectroscopic observations and photometric light curves of 238 nearby M dwarfs from the MEarth exoplanet transit survey, we examine the relationships between magnetic activity (quantified by Hα emission), rotation ...

    • Calibration of the MEarth Photometric System: Optical Magnitudes and Photometric Metallicity Estimates for 1802 Nearby M-dwarfs 

      Dittmann, Jason Adam; Irwin, Jonathan; Charbonneau, David; Newton, Elisabeth R (American Astronomical Society, 2016)
      The MEarth Project is a photometric survey systematically searching the smallest stars nearest to the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected ...

    • Constraints on Planet Occurrence Around Nearby Mid-to-Late M Dwarfs From the Mearth Project 

      Berta, Zachory; Irwin, Jonathan; Charbonneau, David (IOP Publishing, 2013)
      The MEarth Project is a ground-based photometric survey intended to find planets transiting the closest and smallest main-sequence stars. In its first four years, MEarth discovered one transiting exoplanet, the 2.7 R⊕ ...

    • A Disintegrating Minor Planet Transiting a White Dwarf 

      Vanderburg, Andrew Michael; Johnson, John Asher; Rappaport, Saul; Bieryla, Allyson; Irwin, Jonathan; Lewis, John Arban; Kipping, David; Brown, Warren R.; Dufour, Patrick; Ciardi, David R.; Angus, Ruth; Schaefer, Laura Kay; Latham, David Winslow; Charbonneau, David; Beichman, Charles; Eastman, Jason D.; McCrady, Nate; Wittenmyer, Robert A.; Wright, Jason T. (Springer Nature, 2015)
      White dwarfs are the end state of most stars, including the Sun, after they exhaust their nuclear fuel. Between 1/4 and 1/2 of white dwarfs have elements heavier than helium in their atmospheres1,2, even though these ...

    • An Empirical Calibration to Estimate Cool Dwarf Fundamental Parameters From H-Band Spectra 

      Newton, Elisabeth R; Charbonneau, David; Irwin, Jonathan; Mann, Andrew W. (IOP Publishing, 2015)
      Interferometric radius measurements provide a direct probe of the fundamental parameters of M dwarfs. However, interferometry is within reach for only a limited sample of nearby, bright stars. We use interferometrically ...

    • Exoplanet Characterization by Proxy: A Transiting 2.15 R⊕ Planet Near the Habitable Zone of the Late K Dwarf Kepler-61 

      Ballard, Sarah; Charbonneau, David; Fressin, Francois; Torres, Guillermo; Irwin, Jonathan; Desert, Jean-Michel; Newton, Elisabeth R; Mann, Andrew W.; Ciardi, David R.; Crepp, Justin R.; Henze, Christopher E.; Bryson, Stephen T.; Howell, Steven B.; Horch, Elliott P.; Everett, Mark E.; Shporer, Avi (IOP Publishing, 2013)
      We present the validation and characterization of Kepler-61b: a 2.15 R ⊕ planet orbiting near the inner edge of the habitable zone of a low-mass star. Our characterization of the host star Kepler-61 is based upon a comparison ...

    • The Impact of Stellar Rotation on the Detectability of Habitable Planets Around M Dwarfs 

      Newton, Elisabeth R; Irwin, Jonathan; Charbonneau, David; Berta-Thompson, Zachory K.; Dittmann, Jason Adam (American Astronomical Society, 2016)
      Stellar activity and rotation frustrate the detection of exoplanets through the radial velocity technique. This effect is particularly of concern for M dwarfs, which can remain magnetically active for billions of years. ...

    • The MEarth-North and MEarth-South transit surveys: searching for habitable super-Earth exoplanets around nearby M-dwarfs 

      Irwin, Jonathan; Berta-Thompson, Zachory; Charbonneau, David; Dittmann, Jason Adam; Falco, Emilio; Newton, Elisabeth R; Nutzman, Philip (2014)
      Detection and characterization of potentially habitable Earthsize extrasolar planets is one of the major goals of contemporary astronomy. By applying the transit method to very low-mass M-dwarfs, it is possible to find ...

    • Near-Infrared Metallicities, Radial Velocities and Spectral Types for 447 Nearby M Dwarfs 

      Newton, Elisabeth R; Charbonneau, David; Irwin, Jonathan; Berta-Thompson, Zachory K.; Rojas-Ayala, Barbara; Covey, Kevin; Lloyd, James P. (IOP Publishing, 2013)
      We present metallicities, radial velocities, and near-infrared (NIR) spectral types for 447 M dwarfs determined from moderate resolution (R ≈ 2000) NIR spectra obtained with the NASA Infrared Telescope Facility (IRTF)/SpeX. ...

    • A rocky planet transiting a nearby low-mass star 

      Berta-Thompson, Zachory K.; Irwin, Jonathan; Charbonneau, David; Newton, Elisabeth R; Dittmann, Jason Adam; Astudillo-Defru, Nicola; Bonfils, Xavier; Gillon, Michaël; Jehin, Emmanuël; Stark, Antony A.; Stalder, Brian; Bouchy, Francois; Delfosse, Xavier; Forveille, Thierry; Lovis, Christophe; Mayor, Michel; Neves, Vasco; Pepe, Francesco; Santos, Nuno C.; Udry, Stéphane; Wünsche, Anaël (Springer Nature, 2015)
      M-dwarf stars – hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun – are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown ...

    • The Rotation and Galactic Kinematics of Mid M Dwarfs in the Solar Neighborhood 

      Newton, Elisabeth R; Irwin, Jonathan; Charbonneau, David; Berta-Thompson, Zachory K.; Dittmann, Jason Adam; West, Andrew A. (American Astronomical Society, 2016)
      Rotation is a directly observable stellar property, and it drives magnetic field generation and activity through a magnetic dynamo. Main-sequence stars with masses below approximately 0.35 ${M}_{\odot }$ (mid-to-late M ...

    • A Super-Earth Transiting a Nearby Low-Mass Star 

      Charbonneau, David; Berta, Zachory Kaczmarczyk; Irwin, Jonathan M; Burke, Christopher J.; Nutzman, Philip Andrew; Buchhave, Lars A.; Lovis, Christophe; Bonfils, Xavier; Latham, David W.; Udry, Stéphane; Murray-Clay, Ruth Ann; Holman, Matthew J.; Falco, Emilio E.; Winn, Joshua N.; Queloz, Didier; Pepe, Francesco; Mayor, Michel; Delfosse, Xavier; Forveille, Thierry (Nature Publishing Group, 2009)
      A decade ago, the detection of the first transiting extrasolar planet provided a direct constraint on its composition and opened the door to spectroscopic investigations of extrasolar planetary atmospheres. Because such ...

    • Transit detection in the MEarth survey of nearby M dwarfs: bridging the clean-first search-later divide 

      Berta, Zachory; Irwin, Jonathan; Charbonneau, David; Burke, Christopher J.; Falco, Emilio E. (IOP Publishing, 2012)
      In the effort to characterize the masses, radii, and atmospheres of potentially habitable exoplanets, there is an urgent need to find examples of such planets transiting nearby M dwarfs. The MEarth Project is an ongoing ...

    • Trigonometric Parallaxes for 1,507 Nearby Mid-to-late M-dwarfs 

      Dittmann, Jason Adam; Irwin, Jonathan; Charbonneau, David; Berta-Thompson, Zachory K. (IOP Publishing, 2014)
      The MEarth survey is a search for small rocky planets around the smallest, nearest stars to the Sun as identified by high proper motion with red colors. We augmented our planetary search time series with lower cadence ...

    • Zodiacal Exoplanets in Time (Zeit) Iii: A Short-Period Planet Orbiting a Pre-Main-Sequence Star in the Upper Scorpius Ob Association 

      Mann, Andrew W.; Newton, Elisabeth R; Rizzuto, Aaron C.; Irwin, Jonathan; Feiden, Gregory A.; Gaidos, Eric; Mace, Gregory N.; Kraus, Adam L.; James, David J.; Ansdell, Megan; Charbonneau, David; Covey, Kevin R.; Ireland, Michael J.; Jaffe, Daniel T.; Johnson, Marshall C.; Kidder, Benjamin; Vanderburg, Andrew Michael (American Astronomical Society, 2016)
      We confirm and characterize a close-in (Porb = 5.425 days), super-Neptune sized (5.04+0.34 −0.37 R⊕) planet transiting K2-33 (2MASS J16101473-1919095), a late-type (M3) pre-main sequence (11 Myr-old) star in the Upper ...