Browsing by Author "Sasselov, Dimitar"

Now showing items 1-20 of 23

    • A 1.9 Earth Radius Rocky Planet and the Discovery of a Non-Transiting Planet in the Kepler-20 System 

      Buchhave, Lars A.; Dressing, Courtney D.; Dumusque, Xavier; Rice, Ken; Vanderburg, Andrew Michael; Mortier, Annelies; Lopez-Morales, Mercedes; Lopez, Eric; Lundkvist, Mia S.; Kjeldsen, Hans; Affer, Laura; Bonomo, Aldo S.; Charbonneau, David; Cameron, Andrew Collier; Cosentino, Rosario; Figueira, Pedro; Fiorenzano, Aldo F. M.; Harutyunyan, Avet; Haywood, Raphaelle D.; Johnson, John Asher; Latham, David Winslow; Lovis, Christophe; Malavolta, Luca; Mayor, Michel; Micela, Giusi; Molinari, Emilio; Motalebi, Fatemeh; Nascimbeni, Valerio; Pepe, Francesco; Phillips, David F.; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Sasselov, Dimitar D.; Ségransan, Damien; Sozzetti, Alessandro; Udry, Stéphane; Watson, Chris (American Astronomical Society, 2016)
      Kepler-20 is a solar-type star (V = 12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own solar system. A transition from rocky to gaseous planets with a ...

    • An astro-comb calibrated solar telescope to search for the radial velocity signature of Venus 

      Phillips, David F.; Glenday, Alex; Dumusque, Xavier; Buchschacher, Nicolas; Cameron, Andrew Collier; Cecconi, Massimo; Charbonneau, David; Cosentino, Rosario; Ghedina, Adriano; Haywood, Raphaelle D.; Latham, David Winslow; Li, Chih-Hao; Lodi, Marcello; Lovis, Christophe; Molinari, Emilio; Pepe, Francesco; Sasselov, Dimitar D.; Szentgyorgyi, Andrew H.; Udry, Stephane; Walsworth, Ronald Lee (2016)
      We recently demonstrated sub-m/s sensitivity in measuring the radial velocity (RV) between the Earth and Sun using a simple solar telescope feeding the HARPS-N spectrograph at the Italian National Telescope, which is ...

    • Atmospheric Constraints on the Surface UV Environment of Mars at 3.9 Ga Relevant to Prebiotic Chemistry 

      Ranjan, Sukrit; Wordsworth, Robin; Sasselov, Dimitar D. (Mary Ann Liebert Inc, 2017)
      Recent findings suggest Mars may have been a clement environment for the emergence of life, and may even have compared favorably to Earth in this regard. These findings have revived interest in the hypothesis that prebiotically ...

    • Characterizing K2 Planet Discoveries: A Super-Earth Transiting the Bright K Dwarf Hip 116454 

      Vanderburg, Andrew Michael; Montet, Benjamin T.; Johnson, John Asher; Buchhave, Lars A.; Zeng, Li; Pepe, Francesco; Cameron, Andrew Collier; Latham, David Winslow; Molinari, Emilio; Udry, Stéphane; Lovis, Christophe; Matthews, Jaymie M.; Cameron, Chris; Law, Nicholas; Bowler, Brendan P.; Angus, Ruth; Baranec, Christoph; Bieryla, Allyson; Boschin, Walter; Charbonneau, David; Cosentino, Rosario; Dumusque, Xavier; Figueira, Pedro; Guenther, David B.; Harutyunyan, Avet; Hellier, Coel; Kuschnig, Rainer; Lopez-Morales, Mercedes; Mayor, Michel; Micela, Giusi; Moffat, Anthony F. J.; Pedani, Marco; Phillips, David F.; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Rice, Ken; Riddle, Reed; Rowe, Jason F.; Rucinski, Slavek M.; Sasselov, Dimitar D.; Ségransan, Damien; Sozzetti, Alessandro; Szentgyorgyi, Andrew H.; Watson, Chris; Weiss, Werner W. (IOP Publishing, 2015)
      We report the first planet discovery from the two-wheeled Kepler (K2) mission: HIP 116454 b. The host star HIP 116454 is a bright (V = 10.1, K = 8.0) K1 dwarf with high proper motion and a parallax-based distance of 55.2 ...

    • An Earth-sized planet with an Earth-like density 

      Pepe, Francesco; Cameron, Andrew Collier; Latham, David Winslow; Molinari, Emilio; Udry, Stéphane; Bonomo, Aldo S.; Buchhave, Lars A.; Charbonneau, David; Cosentino, Rosario; Dressing, Courtney; Dumusque, Xavier; Figueira, Pedro; Fiorenzano, Aldo F. M.; Gettel, Sara; Harutyunyan, Avet; Haywood, Raphaelle D.; Horne, Keith; Lopez-Morales, Mercedes; Lovis, Christophe; Malavolta, Luca; Mayor, Michel; Micela, Giusi; Motalebi, Fatemeh; Nascimbeni, Valerio; Phillips, David F.; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Rice, Ken; Sasselov, Dimitar D.; Ségransan, Damien; Sozzetti, Alessandro; Szentgyorgyi, Andrew H.; Watson, Christopher A. (Springer Nature, 2013)
      Recent analyses1–4 of data from the NASA Kepler spacecraft5 have established that planets with radii within 25 per cent of Earth’s (R⊕) are commonplace throughout the Galaxy, orbiting at least 16.5 per cent of Sun-like ...

    • A giant impact as the likely origin of different twins in a compact exoplanet system 

      Zeng, Li; Sasselov, Dimitar
      Understanding the origin of the astonishing diversity in the composition of small planets (R p < 3 Earth radii) is one of the most important issues in exoplanetary science. Discoveries range from low-density sub-Neptunes ...

    • Going Over the Cliff: MOOC Dropout Behavior at Chapter Transition 

      Chen, Chen; Sonnert, Gerhard; Sadler, Philip; Sasselov, Dimitar; Fredericks, Colin; Malan, David (Informa UK Limited, 2020-01-02)
      Participants’ engagement in massive online open courses (MOOCs) is highly irregular and self-directed. It is well known in the field of television media that substantial parts of the audience tend to drop out at major ...

    • HARPS-N Observes the Sun as a Star 

      Dumusque, Xavier; Glenday, Alex; Phillips, David F.; Buchschacher, Nicolas; Cameron, Andrew Collier; Cecconi, Massimo; Charbonneau, David; Cosentino, Rosario; Ghedina, Adriano; Latham, David Winslow; Li, Chih-Hao; Lodi, Marcello; Lovis, Christophe; Molinari, Emilio; Pepe, Francesco; Udry, Stéphane; Sasselov, Dimitar D.; Szentgyorgyi, Andrew H.; Walsworth, Ronald Lee (IOP Publishing, 2015)
      Radial velocity (RV) perturbations induced by stellar surface inhomogeneities including spots, plages and granules currently limit the detection of Earth-twins using Doppler spectroscopy. Such stellar noise is poorly ...

    • The HARPS-N Rocky Planet Search 

      Motalebi, F.; Udry, S.; Gillon, M.; Lovis, C.; Ségransan, D.; Buchhave, L. A.; Demory, B. O.; Malavolta, L.; Dressing, Courtney Danielle; Sasselov, Dimitar D.; Rice, K.; Charbonneau, David; Collier Cameron, A.; Latham, David Winslow; Molinari, E.; Pepe, F.; Affer, L.; Bonomo, A. S.; Cosentino, R.; Dumusque, X.; Figueira, P.; Fiorenzano, A. F. M.; Gettel, S.; Harutyunyan, A.; Haywood, Raphaelle D.; Johnson, John Asher; Lopez, E.; Lopez-Morales, Maria Mercedes; Mayor, M.; Micela, G.; Mortier, A.; Nascimbeni, V.; Philips, D.; Piotto, G.; Pollacco, D.; Queloz, D.; Sozzetti, A.; Vanderburg, A.; Watson, C. A. (EDP Sciences, 2015)
      We know now from radial velocity surveys and transit space missions that planets only a few times more massive than our Earth are frequent around solar-type stars. Fundamental questions about their formation history, ...

    • Hues of Habitability: Characterizing Pale Blue Dots Around Other Stars 

      Rugheimer, Sarah M. (2015-05-16)
      A wide range of potentially rocky transiting planets in the habitable zone (HZ) have been detected by Kepler as well as ground-based searches. The spectral type of the host star will influence our ability to detect atmospheric ...

    • The impact of student misconceptions on student persistence in a MOOC 

      Chen, Chen; Sonnert, Gerhard; Sadler, Philip; Sasselov, Dimitar; Fredericks, Colin (Wiley, 2019-12-18)
      Massive Online Open Courses (MOOCs) provide opportunities to learn a vast range of subjects. Because MOOCs are open to anyone with computer access and rarely have prerequisite requirements, the range of student backgrounds ...

    • In-Situ Determination of Astro-Comb Calibrator Lines to Better Than 10 cm \(s^{-1}\) 

      Li, Chih-Hao; Glenday, Alexander Graham; Benedick, Andrew J.; Chang, Guoqing; Chen, Li-Jin; Cramer, Claire; Fendel, Peter; Furesz, Gabor; Kärtner, Franz X.; Korzennik, Sylvain G.; Phillips, David F.; Sasselov, Dimitar D.; Szentgyorgyi, Andrew H.; Walsworth, Ronald Lee (Optical Society of America (OSA), 2010)
      Improved wavelength calibrators for high-resolution astrophysical spectrographs will be essential for precision radial velocity (RV) detection of Earth-like exoplanets and direct observation of cosmological deceleration. ...

    • In-situ determination of astro-comb calibrator lines to better than \(\textrm{10 cm s}^{-1}\) 

      Li, Chih-Hao; Glenday, Alexander G.; Benedick, Andrew J.; Chang, Guoqing; Chen, Li-Jin; Cramer, Claire; Fendel, Peter; Furesz, Gabor; Kärtner, Franz X.; Korzennik, Sylvain G.; Phillips, David M.; Sasselov, Dimitar D.; Szentgyorgyi, Andrew H.; Walsworth, Ronald L. (Optical Society of America, 2010)
      Improved wavelength calibrators for high-resolution astrophysical spectrographs will be essential for precision radial velocity (RV) detection of Earth-like exoplanets and direct observation of cosmological deceleration. ...

    • Interior Structure and Chemistry of Solid Exoplanets 

      Zeng, Li (2015-05-08)
      Understanding the interior structures and chemistry of Earth-like exoplanets is crucial for us to characterize exoplanets, and to find potentially habitable planets. First, I provide a model grid of the mass-radius ...

    • The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet. 

      Dumusque, Xavier; Bonomo, Aldo S.; Haywood, Raphaelle D.; Malavolta, Luca; Ségransan, Damien; Buchhave, Lars A.; Cameron, Andrew Collier; Latham, David Winslow; Molinari, Emilio; Pepe, Francesco; Udry, Stéphane; Charbonneau, David; Cosentino, Rosario; Dressing, Courtney; Figueira, Pedro; Fiorenzano, Aldo F. M.; Gettel, Sara; Harutyunyan, Avet; Horne, Keith; Lopez-Morales, Mercedes; Lovis, Christophe; Mayor, Michel; Micela, Giusi; Motalebi, Fatemeh; Nascimbeni, Valerio; Phillips, David F.; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Rice, Ken; Sasselov, Dimitar D.; Sozzetti, Alessandro; Szentgyorgyi, Andrew H.; Watson, Chris (IOP Publishing, 2014)
      Kepler-10b was the first rocky planet detected by the Kepler satellite and confirmed with radial velocity follow-up observations from Keck-HIRES. The mass of the planet was measured with a precision of around 30%, which ...

    • Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates 

      Gautier, Thomas N.; Charbonneau, David; Rowe, Jason F.; Marcy, Geoffrey W.; Isaacson, Howard; Torres, Guillermo; Fressin, Francois; Rogers, Leslie A.; Désert, Jean-Michel; Buchhave, Lars A.; Latham, David Winslow; Quinn, Samuel N.; Ciardi, David R.; Fabrycky, Daniel C.; Ford, Eric B.; Gilliland, Ronald L.; Walkowicz, Lucianne M.; Bryson, Stephen T.; Cochran, William D.; Endl, Michael; Fischer, Debra A.; Howell, Steve B.; Horch, Elliott P.; Barclay, Thomas; Batalha, Natalie; Borucki, William J.; Christiansen, Jessie L.; Geary, John Charles; Henze, Christopher E.; Holman, Matthew Jon; Ibrahim, Khadeejah; Jenkins, Jon M.; Kinemuchi, Karen; Koch, David G.; Lissauer, Jack J.; Sanderfer, Dwight T.; Sasselov, Dimitar D.; Seager, Sara; Silverio, Kathryn; Smith, Jeffrey C.; Still, Martin; Stumpe, Martin C.; Tenenbaum, Peter; Van Cleve, Jeffrey (IOP Publishing, 2012)
      We present the discovery of the Kepler-20 planetary system, which we initially identified through the detection of five distinct periodic transit signals in the Kepler light curve of the host star 2MASS J19104752+4220194. ...

    • The Kepler-454 System: A Small, Not-rocky Inner Planet, a Jovian World, and a Distant Companion 

      Gettel, Sara; Charbonneau, David; Dressing, Courtney D.; Buchhave, Lars A.; Dumusque, Xavier; Vanderburg, Andrew Michael; Bonomo, Aldo S.; Malavolta, Luca; Pepe, Francesco; Cameron, Andrew Collier; Latham, David Winslow; Udry, Stéphane; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew W.; Davies, Guy R.; Aguirre, Victor Silva; Kjeldsen, Hans; Bedding, Timothy R.; Lopez, Eric; Affer, Laura; Cosentino, Rosario; Figueira, Pedro; Fiorenzano, Aldo F. M.; Harutyunyan, Avet; Johnson, John Asher; Lopez-Morales, Mercedes; Lovis, Christophe; Mayor, Michel; Micela, Giusi; Molinari, Emilio; Motalebi, Fatemeh; Phillips, David F.; Piotto, Giampaolo; Queloz, Didier; Rice, Ken; Sasselov, Dimitar D.; Ségransan, Damien; Sozzetti, Alessandro; Watson, Chris; Basu, Sarbani; Campante, Tiago L.; Christensen-Dalsgaard, Jørgen; Kawaler, Steven D.; Metcalfe, Travis S.; Handberg, Rasmus; Lund, Mikkel N.; Lundkvist, Mia S.; Huber, Daniel; Chaplin, William J. (American Astronomical Society, 2016)
      Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity ...

    • The Mass of Kepler-93b and the Composition of Terrestrial Planets 

      Dressing, Courtney Danielle; Charbonneau, David; Dumusque, Xavier; Gettel, Sara; Pepe, Francesco; Collier Cameron, Andrew; Latham, David Winslow; Molinari, Emilio; Udry, Stéphane; Affer, Laura; Bonomo, Aldo S.; Buchhave, Lars A.; Cosentino, Rosario; Figueira, Pedro; Fiorenzano, Aldo F. M.; Harutyunyan, Avet; Haywood, Raphaelle D.; Johnson, John Asher; Lopez-Morales, Mercedes; Lovis, Christophe; Malavolta, Luca; Mayor, Michel; Micela, Giusi; Motalebi, Fatemeh; Nascimbeni, Valerio; Phillips, David F.; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Rice, Ken; Sasselov, Dimitar D.; Ségransan, Damien; Sozzetti, Alessandro; Szentgyorgyi, Andrew H.; Watson, Chris (IOP Publishing, 2015)
      Kepler-93b is a 1.478 ± 0.019 R⊕ planet with a 4.7 day period around a bright (V = 10.2), astroseismically characterized host star with a mass of 0.911 ± 0.033 M and a radius of 0.919 ± 0.011 R. Based on 86 radial velocity ...

    • The Orbit and Mass of the Third Planet in the Kepler-56 System 

      Otor, Oderah Justin; Montet, Benjamin T.; Johnson, John Asher; Charbonneau, David; Collier-Cameron, Andrew; Howard, Andrew W.; Isaacson, Howard; Latham, David Winslow; Lopez-Morales, Mercedes; Lovis, Christophe; Mayor, Michel; Micela, Giusi; Molinari, Emilio; Pepe, Francesco; Piotto, Giampaolo; Phillips, David F.; Queloz, Didier; Rice, Ken; Sasselov, Dimitar D.; Ségransan, Damien; Sozzetti, Alessandro; Udry, Stéphane; Watson, Chris (American Astronomical Society, 2016)
      While the vast majority of multiple-planet systems have orbital angular momentum axes that align with the spin axis of their host star, Kepler-56 is an exception: its two transiting planets are coplanar yet misaligned by ...

    • Origins of Gas Giant Compositions: The Role of Disk Location and Dynamics 

      Piso, Ana-Maria Adriana (2016-05-04)
      The composition of planets is determined by and tightly linked to the composition of the protoplanetary disk in which they form. In the first part of my thesis, I study giant planet formation through core accretion. I show ...