Transiting exoplanets orbiting young nearby stars are ideal laboratories for testing theories of ... more Transiting exoplanets orbiting young nearby stars are ideal laboratories for testing theories of planet formation and evolution. However, to date only a handful of stars with age <1 Gyr have been found to host transiting exoplanets. Here we present the discovery and validation of a sub-Neptune around HD 18599 , a young (300 Myr), nearby (d = 40 pc) K star. We validate the transiting planet candidate as a bona fide planet using data from the TESS , Spitzer , and Gaia missions, ground-based photometry from IRSF , LCO , PEST , and NGTS , speckle imaging from Gemini, and spectroscopy from CHIRON , NRES , FEROS , and Minerva-Australis . The planet has an orbital period of 4.13 d , and a radius of 2.7 R⊕ . The RV data yields a 3-σ mass upper limit of 30.5 M⊕ which is explained by either a massive companion or the large observed jitter typical for a young star. The brightness of the host star (V∼9 mag) makes it conducive to detailed characterization via Doppler mass measurement which ...
OI-500 (also known as HIP 34269, TIC 134200185 and CD-47 2804) is a high-proper-motion star (Tabl... more OI-500 (also known as HIP 34269, TIC 134200185 and CD-47 2804) is a high-proper-motion star (Table 1) with a radial velocity of 55.6 km s −1 (ref. 1) and a V-band magnitude of 10.54 (ref. 2) located at a distance of 47.39 pc from the Sun 1. The National Aeronautics and Space Administration's (NASA's) Transiting Exoplanet Survey Satellite 3 (TESS) observed TOI-500 for the first time in sectors 6, 7 and 8 between 11 December 2018 and 28 February 2019. The TESS Science Processing Operations Center 4 (SPOC) identified the signature of a possible Earth-sized transiting planet with an orbital period of nearly 13 hours. The candidate was subsequently designated as TOI-500.01 by the TESS Science Office and announced on 8 March 2019. We performed an independent analysis of the TESS light curves with the codes Détection Spécialisée de Transits 5 and Transit Least Square 6 , which confirmed the presence of the candidate (Fig. 1) and excluded additional significant transit signals. We used the Las Cumbres Observatory Global Telescope 7 (LCOGT) to perform photometric observations of the 78 neighbouring stars up to about Δmag ≈ 10 at angular separation between 12″ and 2.5′ from TOI-500 (Extended Data Fig. 1). The analysis of the retrieved light curves allowed us to exclude that those sources are contaminating eclipsing binaries mimicking the transit signal detected in the TESS light curves. Speckle images acquired with the 4.1 m Southern Astrophysical Research (SOAR) telescope (Cerro Tololo Inter-American Observatory, Chile) and the 8.1 m Gemini South telescope (Cerro Pachón, Chile) excluded the presence of nearby stars up to about Δmag ≈ 7, as close as 0.02″ (Zorro@Gemini speckle inner working angle; Extended Data Fig. 2) and out to 3″ (SOAR outer limit; Extended Data Fig. 3). Finally, we confirmed the planetary nature of the transit signal with an intensive radial velocity (RV) follow-up campaign carried out with the High-Accuracy Radial Velocity Planet Searcher 8 (HARPS) spectrograph mounted at the 3.6 m telescope of the European Southern Observatory (ESO, La Silla, Chile). We collected nearly 200 HARPS spectra of TOI-500 between 22 March 2019 and 23 March 2020. Our RV measurements also unveiled the presence of three additional Doppler signals that have no counterpart in any of the stellar activity indicators, providing strong evidence that they are induced by three additional planets (Extended Data Figs. 4-6). TOI-500 is thus orbited by (at least) four planets, three of which are not seen to transit their host star. To determine the planetary parameters, we
We report the discovery of TOI-700 e, a 0.95 R ⊕ planet residing in the Optimistic Habitable Zone... more We report the discovery of TOI-700 e, a 0.95 R ⊕ planet residing in the Optimistic Habitable Zone (HZ) of its host star. This discovery was enabled by multiple years of monitoring from NASA's Transiting Exoplanet Survey Satellite (TESS) mission. The host star, TOI-700 (TIC 150428135), is a nearby (31.1 pc), inactive, M2.5 dwarf (V mag = 13.15). TOI-700 is already known to host three planets, including the small, HZ planet, TOI-700 d. The new planet has an orbital period of 27.8 days and, based on its radius (0.95 R ⊕), it is likely rocky. TOI-700 was observed for 21 sectors over Years 1 and 3 of the TESS mission, including 10 sectors at 20-second cadence in Year 3. Using this full set of TESS data and additional follow-up observations, we identify, validate, and characterize TOI-700 e. This discovery adds another world to the short list of small, HZ planets transiting nearby
Proceedings of the International Astronomical Union, Aug 1, 2006
The Kepler Mission is a space-based photometric mission with a differential photometric precision... more The Kepler Mission is a space-based photometric mission with a differential photometric precision of 14 ppm (at V = 12 for a 6.5 hour transit). It is designed to continuously observe a single field of view (FOV) of greater then 100 square degrees in the Cygnus-Lyra region for four or more years. The primary goal of the mission is to monitor more than one-hundred thousand stars for transits of Earth-size and smaller planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected and light curves produced. To enhance and optimize the mission results, the stellar characteristics for all the stars in the Kepler FOV with V < 16 will have been determined prior to launch. As part of the verification process, stars with transit candidates will have radial-velocity follow-up observations performed to determine the component masses and thereby separate eclipses caused by stellar companions from transits caused by planets. The result will be a rich database on EBs. The community will have access to the archive for further analysis, such as, for EB modeling of the high-precision light curves. A guest observer program is also planned to allow for photometric observations of objects not on the target list but within the FOV.
We report on the discovery and validation of Kepler-452b, a transiting planet identified by a sea... more We report on the discovery and validation of Kepler-452b, a transiting planet identified by a search through the 4 years of data collected by NASA's Kepler Mission. This possibly rocky 1.63 +0.23 −0.20-R ⊕ planet orbits its G2 host star every 384.843 +0.007 −0.012 days, the longest orbital period for a small (R P < 2 R ⊕) transiting exoplanet to date. The likelihood that this planet has a rocky composition lies between 49% and 62%. The star
Proceedings of the International Astronomical Union, May 1, 2008
The Kepler Mission is a space-based mission whose primary goal is to determine the frequency of E... more The Kepler Mission is a space-based mission whose primary goal is to determine the frequency of Earth-size and larger planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for patterns of transits with a differential photometric precision of 20 ppm at V = 12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years. This paper provides a short overview of the mission, a brief history of the mission development, expected results, new investigations by the recently chosen Participating Scientists, and the plans for the Guest Observer and Astrophysical Data Programs.
is a young (∼24 Myr), pre-Main Sequence M dwarf star that was observed in the first month of scie... more is a young (∼24 Myr), pre-Main Sequence M dwarf star that was observed in the first month of science observations of the Transiting Exoplanet Survey Satellite (TESS) and re-observed two years later. This target has photometric variability from a variety of sources that is readily apparent in the TESS light curves; spots induce modulation in the light curve, flares are present throughout (manifesting as sharp rises with slow exponential decay phases), and transits of AU Mic b may be seen by eye as dips in the light curve. We present a combined analysis of both TESS Sector 1 and Sector 27 AU Mic light curves including the new 20-second cadence data from TESS Year 3. We compare flare rates between both observations and analyze the spot evolution, showing that the activity levels increase slightly from Sector 1 to Sector 27. Furthermore, the 20-second data collection allows us to detect more flares, smaller flares, and better resolve flare morphology in white light as compared to the 2-minute data collection mode. We also refine the parameters for AU Mic b by fitting three additional transits of AU Mic b from Sector 27 using a model that includes stellar activity. We show that the transits exhibit clear transit timing variations (TTVs) with an amplitude of ∼80 seconds. We also detect three transits of a 2.8 R ⊕ planet, AU Mic c, which has a period of 18.86 days.
Astrophysical Journal Supplement Series, Jan 10, 2014
We provide updates to the Kepler planet candidate sample based upon nearly two years of high-prec... more We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ∼40% of the sample with R P ∼ 1 R ⊕ and represent ∼40% of the low equilibrium temperature (T eq < 300 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample.
We provide updates to the Kepler planet candidate sample based upon nearly two years of high-prec... more We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ∼40% of the sample with R P ∼ 1 R ⊕ and represent ∼40% of the low equilibrium temperature (T eq < 300 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample.
Doppler planet searches have discovered that giant planets follow orbits with a wide range of orb... more Doppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative
American Astronomical Society Meeting Abstracts #218, May 1, 2011
We describe an initial study into characterizing the completeness of the Kepler data reduction pi... more We describe an initial study into characterizing the completeness of the Kepler data reduction pipeline with respect to detecting transiting planets. The primary goal is to determine the transit detectability for a given set of planet radii and orbital periods of interest for a subset of the Kepler light curves covering a grid of stellar parameter space. We use a
AAS/Division for Planetary Sciences Meeting Abstracts #37, Aug 1, 2005
ABSTRACT A trade study was conducted to quantify the benefits of moving NASA Discovery&#39;s ... more ABSTRACT A trade study was conducted to quantify the benefits of moving NASA Discovery&#39;s Kepler Mission to a higher galactic latitude, b=+13.28° . We examined the extent of the background binary confusion problem relative to the number of primary target stars: those stars for which Kepler can detect transiting habitable planets &gt;= 1; Rearth. A Monte Carlo model of the Field of View (FOV) was constructed with the stellar population modeled using the Besançon galactic model (Robin et al. 2003). The number of primary target stars decreases by 4% and 7% from the original FOV center for a +5° and a +10° increase in b, respectively. We chose late, main sequence stars with 8.5
ABSTRACT The Kepler Mission will be able to detect transiting Earth-size planets in the habitable... more ABSTRACT The Kepler Mission will be able to detect transiting Earth-size planets in the habitable zone of 30,000 stars and 1.4 Earth radius planets around 100,000 stars. Such sensitivity will allow Kepler to detect hundreds of terrestrial planets if they are common, or place significant upper limits on their numbers if they are rare. In addition, Kepler will detect many astrophysical false-positives that mimic transit signals. Most will be background eclipsing binaries as much as nine magnitudes fainter than the target star. We expect 1000 background binaries with periods less than 3 days and 275 with longer periods. We have developed a series of automated tests on each detection, the results of which are used to decide whether planet candidates will be passed on for follow-up imaging and spectroscopic observations. The validation process begins with model planet and eclipsing binary signal fits to the candidate detections. After subtracting the best-fit planet model, we search the residual flux time series for additional transiting planets around the star. This process is repeated until there are no new candidate detections. The candidate’s centroid time series is then tested against the model planet signal(s) in order to eliminate background eclipsing binaries through the change in photocenter position during the eclipse. For a 12th magnitude G2 star we can discriminate a binary mimicking an Earth transit if it is separated from the target star by a quarter of a pixel or more. Tests are also performed to see if the candidate signal is detected anomalously in only a single pixel of the aperture (e.g., a variable bad pixel), or if the signal is seen in the background estimate, or in any of the engineering data (e.g., focal plane temperatures,). Funding for Kepler is provided by NASA’s Discovery Program.
We report the discovery and characterization of a transiting warm sub-Neptune planet around the n... more We report the discovery and characterization of a transiting warm sub-Neptune planet around the nearby bright (V = 8.75 mag, K = 7.15 mag) solar twin HD 183579, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located 56.8 ± 0.1 pc away with a radius of R* = 0.97 ± 0.02 R⊙ and a mass of M* = 1.03 ± 0.05 M⊙. We confirm the planetary nature by combining space and ground-based photometry, spectroscopy, and imaging. We find that HD 183579b (TOI-1055b) has a radius of Rp = 3.53 ± 0.13 R⊕ on a 17.47 d orbit with a mass of Mp = 11.2 ± 5.4 M⊕ (3σ mass upper limit of 27.4 M⊕). HD 183579b is the fifth brightest known sub-Neptune planet system in the sky, making it an excellent target for future studies of the interior structure and atmospheric properties. By performing a line-by-line differential analysis using the high-resolution and signal-to-noise ratio HARPS spectra, we find that HD 183579 joins the typical solar twin sample, without a statistically signific...
We report the first discovery of a transiting circumbinary planet detected from a single sector o... more We report the first discovery of a transiting circumbinary planet detected from a single sector of Transiting Exoplanet Survey Satellite (TESS) data. During Sector 21, the planet TIC 172900988b transited the primary star and then five days later it transited the secondary star. The binary is itself eclipsing, with a period P ≈ 19.7 days and an eccentricity e ≈ 0.45. Archival data from ASAS-SN, Evryscope, KELT, and SuperWASP reveal a prominent apsidal motion of the binary orbit, caused by the dynamical interactions between the binary and the planet. A comprehensive photodynamical analysis of the TESS, archival and follow-up data yields stellar masses and radii of M 1 = 1.2384 ±0.0007 M ⊙ and R 1 = 1.3827 ± 0.0016 R ⊙ for the primary and M 2 = 1.2019 ± 0.0007 M ⊙ and R 2 = 1.3124 ±0.0012 R ⊙ for the secondary. The radius of the planet is R 3 = 11.25 ± 0.44 R ⊕ (1.004 ± 0.039R Jup). The planet’s mass and orbital properties are not uniquely determined—there are six solutions with nearly...
We report the discovery and validation of four extrasolar planets hosted by the nearby, bright, S... more We report the discovery and validation of four extrasolar planets hosted by the nearby, bright, Sunlike (G3V) star HD 108236 using data from the Transiting Exoplanet Survey Satellite (TESS). We present transit photometry, reconnaissance and precise Doppler spectroscopy as well as high-resolution imaging, to validate the planetary nature of the objects transiting HD 108236, also known as the TESS Object of Interest (TOI) 1233. The innermost planet is a possibly-rocky super-Earth with a period of 3.79523 +0.00047 −0.00044 days and has a radius of 1.586 ± 0.098 R ⊕. The outer planets are sub-Neptunes, with potential gaseous envelopes, having radii of 2.068 +0.10 −0.091 R ⊕ , 2.72±0.11 R ⊕ , and 3.12 +0.13 −0.12 R ⊕ and periods of 6.20370 +0.00064 −0.00052 days, 14.17555 +0.00099 −0.0011 days, and 19.5917 +0.0022 −0.0020 days, respectively. With V and K s magnitudes of 9.2 and 7.6, respectively, the bright host star makes the transiting planets favorable targets for mass measurements and, potentially, for atmospheric characterization via transmission spectroscopy. HD 108236 is the brightest Sun-like star in the visual (V) band known to host four or more transiting exoplanets. The discovered planets span a broad range of planetary radii and equilibrium temperatures, and share a common history of insolation from a Sun-like star (R = 0.888 ± 0.017 R , T eff = 5730 ± 50 K), making HD 108236 an exciting, opportune cosmic laboratory for testing models of planet formation and evolution.
Transiting exoplanets orbiting young nearby stars are ideal laboratories for testing theories of ... more Transiting exoplanets orbiting young nearby stars are ideal laboratories for testing theories of planet formation and evolution. However, to date only a handful of stars with age <1 Gyr have been found to host transiting exoplanets. Here we present the discovery and validation of a sub-Neptune around HD 18599 , a young (300 Myr), nearby (d = 40 pc) K star. We validate the transiting planet candidate as a bona fide planet using data from the TESS , Spitzer , and Gaia missions, ground-based photometry from IRSF , LCO , PEST , and NGTS , speckle imaging from Gemini, and spectroscopy from CHIRON , NRES , FEROS , and Minerva-Australis . The planet has an orbital period of 4.13 d , and a radius of 2.7 R⊕ . The RV data yields a 3-σ mass upper limit of 30.5 M⊕ which is explained by either a massive companion or the large observed jitter typical for a young star. The brightness of the host star (V∼9 mag) makes it conducive to detailed characterization via Doppler mass measurement which ...
OI-500 (also known as HIP 34269, TIC 134200185 and CD-47 2804) is a high-proper-motion star (Tabl... more OI-500 (also known as HIP 34269, TIC 134200185 and CD-47 2804) is a high-proper-motion star (Table 1) with a radial velocity of 55.6 km s −1 (ref. 1) and a V-band magnitude of 10.54 (ref. 2) located at a distance of 47.39 pc from the Sun 1. The National Aeronautics and Space Administration's (NASA's) Transiting Exoplanet Survey Satellite 3 (TESS) observed TOI-500 for the first time in sectors 6, 7 and 8 between 11 December 2018 and 28 February 2019. The TESS Science Processing Operations Center 4 (SPOC) identified the signature of a possible Earth-sized transiting planet with an orbital period of nearly 13 hours. The candidate was subsequently designated as TOI-500.01 by the TESS Science Office and announced on 8 March 2019. We performed an independent analysis of the TESS light curves with the codes Détection Spécialisée de Transits 5 and Transit Least Square 6 , which confirmed the presence of the candidate (Fig. 1) and excluded additional significant transit signals. We used the Las Cumbres Observatory Global Telescope 7 (LCOGT) to perform photometric observations of the 78 neighbouring stars up to about Δmag ≈ 10 at angular separation between 12″ and 2.5′ from TOI-500 (Extended Data Fig. 1). The analysis of the retrieved light curves allowed us to exclude that those sources are contaminating eclipsing binaries mimicking the transit signal detected in the TESS light curves. Speckle images acquired with the 4.1 m Southern Astrophysical Research (SOAR) telescope (Cerro Tololo Inter-American Observatory, Chile) and the 8.1 m Gemini South telescope (Cerro Pachón, Chile) excluded the presence of nearby stars up to about Δmag ≈ 7, as close as 0.02″ (Zorro@Gemini speckle inner working angle; Extended Data Fig. 2) and out to 3″ (SOAR outer limit; Extended Data Fig. 3). Finally, we confirmed the planetary nature of the transit signal with an intensive radial velocity (RV) follow-up campaign carried out with the High-Accuracy Radial Velocity Planet Searcher 8 (HARPS) spectrograph mounted at the 3.6 m telescope of the European Southern Observatory (ESO, La Silla, Chile). We collected nearly 200 HARPS spectra of TOI-500 between 22 March 2019 and 23 March 2020. Our RV measurements also unveiled the presence of three additional Doppler signals that have no counterpart in any of the stellar activity indicators, providing strong evidence that they are induced by three additional planets (Extended Data Figs. 4-6). TOI-500 is thus orbited by (at least) four planets, three of which are not seen to transit their host star. To determine the planetary parameters, we
We report the discovery of TOI-700 e, a 0.95 R ⊕ planet residing in the Optimistic Habitable Zone... more We report the discovery of TOI-700 e, a 0.95 R ⊕ planet residing in the Optimistic Habitable Zone (HZ) of its host star. This discovery was enabled by multiple years of monitoring from NASA's Transiting Exoplanet Survey Satellite (TESS) mission. The host star, TOI-700 (TIC 150428135), is a nearby (31.1 pc), inactive, M2.5 dwarf (V mag = 13.15). TOI-700 is already known to host three planets, including the small, HZ planet, TOI-700 d. The new planet has an orbital period of 27.8 days and, based on its radius (0.95 R ⊕), it is likely rocky. TOI-700 was observed for 21 sectors over Years 1 and 3 of the TESS mission, including 10 sectors at 20-second cadence in Year 3. Using this full set of TESS data and additional follow-up observations, we identify, validate, and characterize TOI-700 e. This discovery adds another world to the short list of small, HZ planets transiting nearby
Proceedings of the International Astronomical Union, Aug 1, 2006
The Kepler Mission is a space-based photometric mission with a differential photometric precision... more The Kepler Mission is a space-based photometric mission with a differential photometric precision of 14 ppm (at V = 12 for a 6.5 hour transit). It is designed to continuously observe a single field of view (FOV) of greater then 100 square degrees in the Cygnus-Lyra region for four or more years. The primary goal of the mission is to monitor more than one-hundred thousand stars for transits of Earth-size and smaller planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected and light curves produced. To enhance and optimize the mission results, the stellar characteristics for all the stars in the Kepler FOV with V < 16 will have been determined prior to launch. As part of the verification process, stars with transit candidates will have radial-velocity follow-up observations performed to determine the component masses and thereby separate eclipses caused by stellar companions from transits caused by planets. The result will be a rich database on EBs. The community will have access to the archive for further analysis, such as, for EB modeling of the high-precision light curves. A guest observer program is also planned to allow for photometric observations of objects not on the target list but within the FOV.
We report on the discovery and validation of Kepler-452b, a transiting planet identified by a sea... more We report on the discovery and validation of Kepler-452b, a transiting planet identified by a search through the 4 years of data collected by NASA's Kepler Mission. This possibly rocky 1.63 +0.23 −0.20-R ⊕ planet orbits its G2 host star every 384.843 +0.007 −0.012 days, the longest orbital period for a small (R P < 2 R ⊕) transiting exoplanet to date. The likelihood that this planet has a rocky composition lies between 49% and 62%. The star
Proceedings of the International Astronomical Union, May 1, 2008
The Kepler Mission is a space-based mission whose primary goal is to determine the frequency of E... more The Kepler Mission is a space-based mission whose primary goal is to determine the frequency of Earth-size and larger planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for patterns of transits with a differential photometric precision of 20 ppm at V = 12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years. This paper provides a short overview of the mission, a brief history of the mission development, expected results, new investigations by the recently chosen Participating Scientists, and the plans for the Guest Observer and Astrophysical Data Programs.
is a young (∼24 Myr), pre-Main Sequence M dwarf star that was observed in the first month of scie... more is a young (∼24 Myr), pre-Main Sequence M dwarf star that was observed in the first month of science observations of the Transiting Exoplanet Survey Satellite (TESS) and re-observed two years later. This target has photometric variability from a variety of sources that is readily apparent in the TESS light curves; spots induce modulation in the light curve, flares are present throughout (manifesting as sharp rises with slow exponential decay phases), and transits of AU Mic b may be seen by eye as dips in the light curve. We present a combined analysis of both TESS Sector 1 and Sector 27 AU Mic light curves including the new 20-second cadence data from TESS Year 3. We compare flare rates between both observations and analyze the spot evolution, showing that the activity levels increase slightly from Sector 1 to Sector 27. Furthermore, the 20-second data collection allows us to detect more flares, smaller flares, and better resolve flare morphology in white light as compared to the 2-minute data collection mode. We also refine the parameters for AU Mic b by fitting three additional transits of AU Mic b from Sector 27 using a model that includes stellar activity. We show that the transits exhibit clear transit timing variations (TTVs) with an amplitude of ∼80 seconds. We also detect three transits of a 2.8 R ⊕ planet, AU Mic c, which has a period of 18.86 days.
Astrophysical Journal Supplement Series, Jan 10, 2014
We provide updates to the Kepler planet candidate sample based upon nearly two years of high-prec... more We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ∼40% of the sample with R P ∼ 1 R ⊕ and represent ∼40% of the low equilibrium temperature (T eq < 300 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample.
We provide updates to the Kepler planet candidate sample based upon nearly two years of high-prec... more We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ∼40% of the sample with R P ∼ 1 R ⊕ and represent ∼40% of the low equilibrium temperature (T eq < 300 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample.
Doppler planet searches have discovered that giant planets follow orbits with a wide range of orb... more Doppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative
American Astronomical Society Meeting Abstracts #218, May 1, 2011
We describe an initial study into characterizing the completeness of the Kepler data reduction pi... more We describe an initial study into characterizing the completeness of the Kepler data reduction pipeline with respect to detecting transiting planets. The primary goal is to determine the transit detectability for a given set of planet radii and orbital periods of interest for a subset of the Kepler light curves covering a grid of stellar parameter space. We use a
AAS/Division for Planetary Sciences Meeting Abstracts #37, Aug 1, 2005
ABSTRACT A trade study was conducted to quantify the benefits of moving NASA Discovery&#39;s ... more ABSTRACT A trade study was conducted to quantify the benefits of moving NASA Discovery&#39;s Kepler Mission to a higher galactic latitude, b=+13.28° . We examined the extent of the background binary confusion problem relative to the number of primary target stars: those stars for which Kepler can detect transiting habitable planets &gt;= 1; Rearth. A Monte Carlo model of the Field of View (FOV) was constructed with the stellar population modeled using the Besançon galactic model (Robin et al. 2003). The number of primary target stars decreases by 4% and 7% from the original FOV center for a +5° and a +10° increase in b, respectively. We chose late, main sequence stars with 8.5
ABSTRACT The Kepler Mission will be able to detect transiting Earth-size planets in the habitable... more ABSTRACT The Kepler Mission will be able to detect transiting Earth-size planets in the habitable zone of 30,000 stars and 1.4 Earth radius planets around 100,000 stars. Such sensitivity will allow Kepler to detect hundreds of terrestrial planets if they are common, or place significant upper limits on their numbers if they are rare. In addition, Kepler will detect many astrophysical false-positives that mimic transit signals. Most will be background eclipsing binaries as much as nine magnitudes fainter than the target star. We expect 1000 background binaries with periods less than 3 days and 275 with longer periods. We have developed a series of automated tests on each detection, the results of which are used to decide whether planet candidates will be passed on for follow-up imaging and spectroscopic observations. The validation process begins with model planet and eclipsing binary signal fits to the candidate detections. After subtracting the best-fit planet model, we search the residual flux time series for additional transiting planets around the star. This process is repeated until there are no new candidate detections. The candidate’s centroid time series is then tested against the model planet signal(s) in order to eliminate background eclipsing binaries through the change in photocenter position during the eclipse. For a 12th magnitude G2 star we can discriminate a binary mimicking an Earth transit if it is separated from the target star by a quarter of a pixel or more. Tests are also performed to see if the candidate signal is detected anomalously in only a single pixel of the aperture (e.g., a variable bad pixel), or if the signal is seen in the background estimate, or in any of the engineering data (e.g., focal plane temperatures,). Funding for Kepler is provided by NASA’s Discovery Program.
We report the discovery and characterization of a transiting warm sub-Neptune planet around the n... more We report the discovery and characterization of a transiting warm sub-Neptune planet around the nearby bright (V = 8.75 mag, K = 7.15 mag) solar twin HD 183579, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located 56.8 ± 0.1 pc away with a radius of R* = 0.97 ± 0.02 R⊙ and a mass of M* = 1.03 ± 0.05 M⊙. We confirm the planetary nature by combining space and ground-based photometry, spectroscopy, and imaging. We find that HD 183579b (TOI-1055b) has a radius of Rp = 3.53 ± 0.13 R⊕ on a 17.47 d orbit with a mass of Mp = 11.2 ± 5.4 M⊕ (3σ mass upper limit of 27.4 M⊕). HD 183579b is the fifth brightest known sub-Neptune planet system in the sky, making it an excellent target for future studies of the interior structure and atmospheric properties. By performing a line-by-line differential analysis using the high-resolution and signal-to-noise ratio HARPS spectra, we find that HD 183579 joins the typical solar twin sample, without a statistically signific...
We report the first discovery of a transiting circumbinary planet detected from a single sector o... more We report the first discovery of a transiting circumbinary planet detected from a single sector of Transiting Exoplanet Survey Satellite (TESS) data. During Sector 21, the planet TIC 172900988b transited the primary star and then five days later it transited the secondary star. The binary is itself eclipsing, with a period P ≈ 19.7 days and an eccentricity e ≈ 0.45. Archival data from ASAS-SN, Evryscope, KELT, and SuperWASP reveal a prominent apsidal motion of the binary orbit, caused by the dynamical interactions between the binary and the planet. A comprehensive photodynamical analysis of the TESS, archival and follow-up data yields stellar masses and radii of M 1 = 1.2384 ±0.0007 M ⊙ and R 1 = 1.3827 ± 0.0016 R ⊙ for the primary and M 2 = 1.2019 ± 0.0007 M ⊙ and R 2 = 1.3124 ±0.0012 R ⊙ for the secondary. The radius of the planet is R 3 = 11.25 ± 0.44 R ⊕ (1.004 ± 0.039R Jup). The planet’s mass and orbital properties are not uniquely determined—there are six solutions with nearly...
We report the discovery and validation of four extrasolar planets hosted by the nearby, bright, S... more We report the discovery and validation of four extrasolar planets hosted by the nearby, bright, Sunlike (G3V) star HD 108236 using data from the Transiting Exoplanet Survey Satellite (TESS). We present transit photometry, reconnaissance and precise Doppler spectroscopy as well as high-resolution imaging, to validate the planetary nature of the objects transiting HD 108236, also known as the TESS Object of Interest (TOI) 1233. The innermost planet is a possibly-rocky super-Earth with a period of 3.79523 +0.00047 −0.00044 days and has a radius of 1.586 ± 0.098 R ⊕. The outer planets are sub-Neptunes, with potential gaseous envelopes, having radii of 2.068 +0.10 −0.091 R ⊕ , 2.72±0.11 R ⊕ , and 3.12 +0.13 −0.12 R ⊕ and periods of 6.20370 +0.00064 −0.00052 days, 14.17555 +0.00099 −0.0011 days, and 19.5917 +0.0022 −0.0020 days, respectively. With V and K s magnitudes of 9.2 and 7.6, respectively, the bright host star makes the transiting planets favorable targets for mass measurements and, potentially, for atmospheric characterization via transmission spectroscopy. HD 108236 is the brightest Sun-like star in the visual (V) band known to host four or more transiting exoplanets. The discovered planets span a broad range of planetary radii and equilibrium temperatures, and share a common history of insolation from a Sun-like star (R = 0.888 ± 0.017 R , T eff = 5730 ± 50 K), making HD 108236 an exciting, opportune cosmic laboratory for testing models of planet formation and evolution.
Uploads
Papers by Jon Jenkins