Now showing items 1-20 of 20

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

(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 ﻿

(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 ﻿

(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 ﻿

(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 ﻿

(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 ...
• #### HARPS-N Observes the Sun as a Star ﻿

(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 ﻿

(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 ﻿

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

(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 $\textrm{10 cm s}^{-1}$ ﻿

(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 ﻿

(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. ﻿

(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 ﻿

(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 ﻿

(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 ﻿

(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 ﻿

(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 ﻿

(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 ...
• #### The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up ﻿

(American Astronomical Society, 2017)
Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational ...
• #### Transiting Exoplanet Survey Satellite ﻿

(SPIE-Intl Soc Optical Eng, 2014)
The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be ...
• #### Two Earth-sized planets orbiting Kepler-20 ﻿

(Springer Nature, 2011)
Since the discovery of the first extrasolar giant planets around Sun-like stars1,2, evolving observational capabilities have brought us closer to the detection of true Earth analogues. The size of an exoplanet can be ...