ORCID Profile
0000-0001-7204-6727
Current Organisation
Princeton University
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Publisher: Springer Science and Business Media LLC
Date: 02-08-2012
Publisher: American Astronomical Society
Date: 11-08-2017
Publisher: IOP Publishing
Date: 09-2021
Publisher: American Astronomical Society
Date: 20-12-0002
Publisher: American Astronomical Society
Date: 14-01-2021
Publisher: American Astronomical Society
Date: 30-11-2018
Publisher: American Astronomical Society
Date: 28-04-2015
Publisher: American Astronomical Society
Date: 21-03-2007
DOI: 10.1086/517971
Publisher: American Astronomical Society
Date: 02-02-2017
Publisher: Wiley
Date: 10-2007
Publisher: EDP Sciences
Date: 10-2013
Publisher: American Astronomical Society
Date: 11-09-2019
Publisher: American Astronomical Society
Date: 14-08-2013
Publisher: EDP Sciences
Date: 08-2015
Publisher: American Astronomical Society
Date: 25-08-2015
Publisher: American Astronomical Society
Date: 22-01-2021
Publisher: American Astronomical Society
Date: 25-01-2019
Publisher: American Astronomical Society
Date: 03-06-2011
Publisher: Oxford University Press (OUP)
Date: 12-06-2015
Publisher: American Astronomical Society
Date: 11-02-2022
Abstract: The relative rarity of giant planets around low-mass stars compared with solar-type stars is a key prediction from the core-accretion planet formation theory. In this paper we report on the discovery of four gas giant planets that transit low-mass late K and early M dwarfs. The planets HATS-74Ab (TOI 737b), HATS-75b (TOI 552b), HATS-76b (TOI 555b), and HATS-77b (TOI 730b) were all discovered from the HATSouth photometric survey and follow-up using TESS and other photometric facilities. We use the new ESPRESSO facility at the VLT to confirm systems and measure their masses. We find that these planets have masses of 1.46 ± 0.14 M J, 0.491 ± 0.039 M J, 2.629 ± 0.089 M J, and 1.374 − 0.074 + 0.100 M J, respectively, and radii of 1.032 ± 0.021 R J, 0.884 ± 0.013 R J, 1.079 ± 0.031 R J, and 1.165 ± 0.021 R J, respectively. The planets all orbit close to their host stars with orbital periods ranging from 1.7319 days to 3.0876 days. With further work, we aim to test core-accretion theory by using these and further discoveries to quantify the occurrence rate of giant planets around low-mass host stars.
Publisher: American Astronomical Society
Date: 20-10-2016
Publisher: American Astronomical Society
Date: 21-09-2016
Publisher: American Astronomical Society
Date: 18-05-2020
Publisher: IOP Publishing
Date: 10-06-2016
Publisher: Oxford University Press (OUP)
Date: 09-06-2014
DOI: 10.1093/MNRAS/STU906
Publisher: American Astronomical Society
Date: 02-01-2019
Publisher: American Astronomical Society
Date: 03-2023
Abstract: We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry and confirmed with radial velocities from ESPRESSO and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of 0.665 ± 0.025 M J and a radius of 1.017 ± 0.044 R J . It orbits close to its host star, with an orbital period of 2.5926 days but has an equilibrium temperature of ≈ 604 K, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of 0.3939 ± 0.0030 M ☉ , a radius of 0.3697 ± 0.0018 R ☉ , an effective temperature of 3389 K, and a J -band magnitude of 11.706 ± 0.025. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M dwarfs for atmospheric characterization.
Publisher: IOP Publishing
Date: 02-2013
DOI: 10.1086/669529
Publisher: American Astronomical Society
Date: 17-07-2015
Publisher: American Astronomical Society
Date: 21-11-2012
Publisher: American Astronomical Society
Date: 16-08-2011
Publisher: American Astronomical Society
Date: 07-07-2015
Publisher: American Astronomical Society
Date: 10-12-2015
Publisher: American Astronomical Society
Date: 16-07-2019
Publisher: American Astronomical Society
Date: 08-03-2016
Publisher: American Astronomical Society
Date: 19-11-2015
Publisher: Oxford University Press (OUP)
Date: 11-2013
Publisher: American Astronomical Society
Date: 08-06-2021
Publisher: EDP Sciences
Date: 07-2020
DOI: 10.1051/0004-6361/202037941
Abstract: We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright ( V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 M J planet in a grazing transit configuration with an impact parameter of b = 1.17 −0.08 +0.10 . As a result the radius is poorly constrained, 2.03 −0.49 +0.61 R J . The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Q s ′ = 10 7 − 10 9 . We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13 M J and a radius of 1.29 ± 0.02 R J . It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star ( V = 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V = 12.4 G-type star. It has a mass of 0.79 ±0.06 M J and a radius of 1.09 −0.05 +0.08 R J . Despite having the longest orbital period ( P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with [Fe / H] ranging from 0.18 to0.24.
Publisher: American Astronomical Society
Date: 03-11-2020
Publisher: American Astronomical Society
Date: 14-11-2016
Publisher: American Astronomical Society
Date: 06-2021
Publisher: Oxford University Press (OUP)
Date: 28-02-2017
DOI: 10.1093/MNRAS/STX500
Publisher: Cambridge University Press (CUP)
Date: 06-2013
DOI: 10.1017/S1743921313009058
Abstract: We measured the spin-orbit misalignment for WASP-79b, a transiting hot Jupiter from the WASP survey. Using the Rossiter-McLaughlin effect during the transit event, we determined the sky-projected obliquity to be λ = −106 +10 −8 ○. This result indicates that the planet is in a nearly polar orbit.
Publisher: American Astronomical Society
Date: 22-10-2015
Publisher: American Astronomical Society
Date: 27-09-2013
Publisher: American Astronomical Society
Date: 18-10-2018
Publisher: American Astronomical Society
Date: 29-10-2020
Abstract: We present the discovery of two new 10 day period giant planets from the Transiting Exoplanet Survey Satellite mission, whose masses were precisely determined using a wide ersity of ground-based facilities. TOI-481 b and TOI-892 b have similar radii (0.99 ± 0.01 R J and 1.07 ± 0.02 R J , respectively), and orbital periods (10.3311 days and 10.6266 days, respectively), but significantly different masses (1.53 ± 0.03 M J versus 0.95 ± 0.07 M J , respectively). Both planets orbit metal-rich stars ( [ Fe / H ] = + 0.26 ± 0.05 dex and [ Fe / H ] = + 0.24 ± 0.05 for TOI-481 and TOI-892, respectively) but at different evolutionary stages. TOI-481 is a M ⋆ = 1.14 ± 0.02 M ⊙ , R ⋆ = 1.66 ± 0.02 R ⊙ G-type star ( T eff = 5735 ± 72 K), that with an age of 6.7 Gyr, is in the turn-off point of the main sequence. TOI-892 on the other hand, is a F-type dwarf star ( T eff = 6261 ± 80 K), which has a mass of M ⋆ = 1.28 ± 0.03 M ⊙ and a radius of R ⋆ = 1.39 ± 0.02 R ⊙ . TOI-481 b and TOI-892 b join the scarcely populated region of transiting gas giants with orbital periods longer than 10 days, which is important to constrain theories of the formation and structure of hot Jupiters.
Publisher: American Astronomical Society
Date: 27-10-2020
Publisher: American Astronomical Society
Date: 06-02-2019
Publisher: American Astronomical Society
Date: 04-11-2015
Publisher: EDP Sciences
Date: 08-2021
DOI: 10.1051/0004-6361/202141145
Abstract: We report the discovery of five transiting companions near the hydrogen-burning mass limit in close orbits around main sequence stars originally identified by the Transiting Exoplanet Survey Satellite (TESS) as TESS objects of interest (TOIs): TOI-148, TOI-587, TOI-681, TOI-746, and TOI-1213. Using TESS and ground-based photometry as well as radial velocities from the CORALIE, CHIRON, TRES, and FEROS spectrographs, we found the companions have orbital periods between 4.8 and 27.2 days, masses between 77 and 98 M Jup , and radii between 0.81 and 1.66 R Jup . These targets have masses near the uncertain lower limit of hydrogen core fusion (~73-96 M Jup ), which separates brown dwarfs and low-mass stars. We constrained young ages for TOI-587 (0.2 ± 0.1 Gyr) and TOI-681 (0.17 ± 0.03 Gyr) and found them to have relatively larger radii compared to other transiting companions of a similar mass. Conversely we estimated older ages for TOI-148 and TOI-746 and found them to have relatively smaller companion radii. With an effective temperature of 9800 ± 200 K, TOI-587 is the hottest known main-sequence star to host a transiting brown dwarf or very low-mass star. We found evidence of spin-orbit synchronization for TOI-148 and TOI-746 as well as tidal circularization for TOI-148. These companions add to the population of brown dwarfs and very low-mass stars with well measured parameters ideal to test formation models of these rare objects, the origin of the brown dwarf desert, and the distinction between brown dwarfs and hydrogen-burning main sequence stars.
Publisher: American Astronomical Society
Date: 09-2000
DOI: 10.1086/309340
Publisher: American Astronomical Society
Date: 26-03-2020
Publisher: American Astronomical Society
Date: 15-02-2018
Publisher: American Astronomical Society
Date: 18-01-2019
Publisher: American Astronomical Society
Date: 26-06-2014
Publisher: American Astronomical Society
Date: 06-05-0011
Publisher: IOP Publishing
Date: 22-02-2017
Publisher: Oxford University Press (OUP)
Date: 28-10-2015
Publisher: American Astronomical Society
Date: 22-01-2018
Publisher: Cambridge University Press (CUP)
Date: 10-2010
DOI: 10.1017/S1743921311020448
Abstract: The science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are? In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spitzer, Hubble, and large ground-based telescopes the spectra of bright close-in massive planets can be obtained and species like water vapour, methane, carbon monoxide and dioxide have been detected. With transit science came the first tangible remote sensing of these planetary bodies and so one can start to extrapolate from what has been learnt from Solar System probes to what one might plan to learn about their faraway siblings. As we learn more about the atmospheres, surfaces and near-surfaces of these remote bodies, we will begin to build up a clearer picture of their construction, history and suitability for life. The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. By characterising spectroscopically more bodies in different environments we will take detailed planetology out of the Solar System and into the Galaxy as a whole. EChO has now been selected by the European Space Agency to be assessed as one of four M3 mission candidates.
Publisher: American Astronomical Society
Date: 20-01-2015
Publisher: Oxford University Press (OUP)
Date: 22-12-2012
DOI: 10.1093/MNRAS/STS463
Publisher: American Astronomical Society
Date: 13-02-2018
Publisher: American Astronomical Society
Date: 04-10-2016
Publisher: Oxford University Press (OUP)
Date: 20-03-2018
DOI: 10.1093/MNRAS/STY726
No related grants have been discovered for Gaspar Bakos.