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result(s) for
"Brahm, Rafael"
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CERES: A Set of Automated Routines for Echelle Spectra
by
Espinoza, Néstor
,
Brahm, Rafael
,
Jordán, Andrés
in
methods: data analysis
,
planets and satellites: detection
,
techniques: radial velocities
2017
We present the Collection of Elemental Routines for Echelle Spectra (CERES). These routines were developed for the construction of automated pipelines for the reduction, extraction, and analysis of spectra acquired with different instruments, allowing the obtention of homogeneous and standardized results. This modular code includes tools for handling the different steps of the processing: CCD image reductions; identification and tracing of the echelle orders; optimal and rectangular extraction; computation of the wavelength solution; estimation of radial velocities; and rough and fast estimation of the atmospheric parameters. Currently, CERES has been used to develop automated pipelines for 13 different spectrographs, namely CORALIE, FEROS, HARPS, ESPaDOnS, FIES, PUCHEROS, FIDEOS, CAFE, DuPont/Echelle, Magellan/Mike, Keck/HIRES, Magellan/PFS, and APO/ARCES, but the routines can be easily used to deal with data coming from other spectrographs. We show the high precision in radial velocity that CERES achieves for some of these instruments, and we briefly summarize some results that have already been obtained using the CERES pipelines.
Journal Article
Inhomogeneous terminators on the exoplanet WASP-39 b
by
Lewis, David A.
,
Mancini, Luigi
,
Zamyatina, Maria
in
639/33/34/862
,
639/33/445/862
,
Chemical properties
2024
Transmission spectroscopy has been a workhorse technique used over the past two decades to constrain the physical and chemical properties of exoplanet atmospheres
1
–
5
. One of its classical key assumptions is that the portion of the atmosphere it probes—the terminator region—is homogeneous. Several works from the past decade, however, have put this into question for highly irradiated, hot (
T
eq
≳ 1,000 K) gas giant exoplanets, both empirically
6
–
10
and through three-dimensional modelling
11
–
17
. While models have predicted clear differences between the evening (day-to-night) and morning (night-to-day) terminators, direct morning and evening transmission spectra in a wide wavelength range have not been reported for an exoplanet so far. Under the assumption of precise and accurate orbital parameters for the exoplanet WASP-39 b, here we report the detection of inhomogeneous terminators on WASP-39 b, which has allowed us to retrieve its morning and evening transmission spectra in the near-infrared (2–5 μm) using the James Webb Space Telescope. We have observed larger transit depths in the evening, which are, on average, 405 ± 88 ppm larger than the morning ones, and also have qualitatively larger features than the morning spectrum. The spectra are best explained by models in which the evening terminator is hotter than the morning terminator by
17
7
−
57
+
65
K, with both terminators having C/O ratios consistent with solar. General circulation models predict temperature differences broadly consistent with the above value and point towards a cloudy morning terminator and a clearer evening terminator.
The atmospheric terminator region of WASP-39 b, a hot gas giant exoplanet, is inhomogeneous, despite past assumptions, with the evening terminator being hotter and thus probably clearer, and the morning terminator probably being cloudy and consequently cooler.
Journal Article
CERES
by
Espinoza, Néstor
,
Brahm, Rafael
,
Jordán, Andrés
in
Astronomical Software, Data Analysis, and Techniques
2017
We present the Collection of Elemental Routines for Echelle Spectra (CERES). These routines were developed for the construction of automated pipelines for the reduction, extraction, and analysis of spectra acquired with different instruments, allowing the obtention of homogeneous and standardized results. This modular code includes tools for handling the different steps of the processing: CCD image reductions; identification and tracing of the echelle orders; optimal and rectangular extraction; computation of the wavelength solution; estimation of radial velocities; and rough and fast estimation of the atmospheric parameters. Currently, CERES has been used to develop automated pipelines for 13 different spectrographs, namely CORALIE, FEROS, HARPS, ESPaDOnS, FIES, PUCHEROS, FIDEOS, CAFE, DuPont/Echelle, Magellan/Mike, Keck/HIRES, Magellan/PFS, and APO/ARCES, but the routines can be easily used to deal with data coming from other spectrographs. We show the high precision in radial velocity that CERES achieves for some of these instruments, and we briefly summarize some results that have already been obtained using the CERES pipelines.
Journal Article
An Independent Discovery of Two Hot Jupiters from the K2 Mission
We report the discovery of two hot Jupiters using photometry from Campaigns 4 and 5 of the two-wheeled Kepler (K2) mission. K2-30b has a mass of 0.589 0.023 MJ, a radius of 1.069 0.021 RJ, and transits its G dwarf (Teff = 5675 50 K), slightly metal-rich ([Fe/H] = +0.06 0.04 dex) host star in a 4.1 day circular orbit. K2-34b has a mass of 1.698 0.055 MJ, a radius of 1.377 0.014 RJ =, and an orbital period of 3.0 days in which it orbits a late F dwarf (Teff = 6149 55 K) solar metallicity star. Both planets were confirmed via precision radial velocity (RV) measurements obtained with three spectrographs from the southern hemisphere. They have physical and orbital properties similar to the ones of the already uncovered population of hot Jupiters and are well-suited candidates for further orbital and atmospheric characterization via detailed follow-up observations. Given that the discovery of both systems was recently reported by other groups we take the opportunity of refining the planetary parameters by including the RVs obtained by these independent studies in our global analysis.
Journal Article
TESS light curves of low-mass detached eclipsing binaries
by
Espinoza, Nestor
,
Jordán, Andrés
,
Brahm, Rafael
in
Astronomy
,
Contributed Papers
,
Extrasolar planets
2019
We present high-precision light curves of several M- and K-type, active detached eclipsing binaries (DEBs), recorded with 2-minute cadence by the Transiting Exoplanet Survey Satellite (TESS). Analysis of these curves, combined with new and literature radial velocity (RV) data, allows to vastly improve the accuracy and precision of stellar parameters with respect to previous studies of these systems. Results for one previously unpublished DEB are also presented.
Journal Article
An Independent Discovery of Two Hot Jupiters from the K2 Mission
by
Espinoza, Néstor
,
Pantoja, Blake
,
Jenkins, James S.
in
Astronomical photometry
,
Brown Dwarfs, Planets, and Planetary Systems (Including the Solar System)
,
Hot Jupiters
2016
We report the discovery of two hot Jupiters using photometry from Campaigns 4 and 5 of the two-wheeled Kepler (K2) mission. K2-30b has a mass of 0.589 ± 0.023 MJ
, a radius of 1.069 ± 0.021 RJ
, and transits its G dwarf (T
eff = 5675 ± 50 K), slightly metal-rich ([Fe/H] = +0.06 ± 0.04 dex) host star in a 4.1 day circular orbit. K2-34b has a mass of 1.698 ± 0.055 MJ
, a radius of 1.377 ± 0.014 RJ
=, and an orbital period of 3.0 days in which it orbits a late F dwarf (T
eff = 6149 ± 55 K) solar metallicity star. Both planets were confirmed via precision radial velocity (RV) measurements obtained with three spectrographs from the southern hemisphere. They have physical and orbital properties similar to the ones of the already uncovered population of hot Jupiters and are well-suited candidates for further orbital and atmospheric characterization via detailed follow-up observations. Given that the discovery of both systems was recently reported by other groups we take the opportunity of refining the planetary parameters by including the RVs obtained by these independent studies in our global analysis.
Journal Article
An Independent Discovery of Two Hot Jupiters from the K 2 Mission
2016
We report the discovery of two hot Jupiters using photometry from Campaigns 4 and 5 of the two-wheeled Kepler(K2) mission. K2-30b has a mass of 0.589 + or - 0.023 MJ, a radius of 1.069 + or - 0.021 RJ, and transits its G dwarf (T sub(eff)= 5675 + or - 50 K), slightly metal-rich ([Fe/H] = +0.06 + or - 0.04 dex) host star in a 4.1 day circular orbit. K2-34b has a mass of 1.698 + or - 0.055 MJ, a radius of 1.377 + or - 0.014 RJ=, and an orbital period of 3.0 days in which it orbits a late F dwarf (T sub(eff)= 6149 + or - 55 K) solar metallicity star. Both planets were confirmed via precision radial velocity (RV) measurements obtained with three spectrographs from the southern hemisphere. They have physical and orbital properties similar to the ones of the already uncovered population of hot Jupiters and are well-suited candidates for further orbital and atmospheric characterization via detailed follow-up observations. Given that the discovery of both systems was recently reported by other groups we take the opportunity of refining the planetary parameters by including the RVs obtained by these independent studies in our global analysis.
Journal Article
The Similar Seven: A set of very-alike exoplanets to test correlations between system parameters and atmospheric properties
by
Brahm, Rafael
,
Jordán, Andrés
,
López-Morales, Mercedes
in
Aerosols
,
Extrasolar planets
,
High altitude
2023
Studies of exoplanetary atmospheres have found no definite correlations between observed high altitude aerosols and other system parameters. This could be, in part, because of the lack of homogeneous exoplanet samples for which specific parameters can be isolated and inspected. Here we present a set of seven exoplanets with very similar system parameters. We analyze existing photometric timeseries, Gaia parallax, and high-resolution spectroscopic data to produce a new set of homogeneous stellar, planetary, and orbital parameters for these systems. With this we confirm that most measured parameters for all systems are very similar, except for the host stars' metallicities and possibly high energy irradiation levels, which require UV and X-ray observations to constrain. From the sample, WASP-6b, WASP-96b and WASP-110b, have observed transmission spectra that we use to estimate their aerosol coverage levels using the Na I doublet 5892.9Å. We find a tentative correlation between the metallicity of the host stars and the planetary aerosol levels. The trend we find with stellar metallicity can be tested by observing transmission spectra of the remaining planets in the sample. Based on our prediction, WASP-25b and WASP-55b should have higher levels of aerosols than WASP-124b and HATS-29b. Finally, we highlight how targeted surveys of alike planets like the ones presented here might prove key for identifying driving factors for atmospheric properties of exoplanets in the future and could be used as a sample selection criterium for future observations with e.g. JWST, ARIEL, and the next generation of ground-based telescopes.
Orbital alignment of the eccentric warm Jupiter TOI-677 b
by
Muñoz, Diego J
,
Hobson, Melissa J
,
Jordán, Andrés
in
Alignment
,
Axes of rotation
,
Extrasolar planets
2023
Warm Jupiters lay out an excellent laboratory for testing models of planet formation and migration. Their separation from the host star makes tidal reprocessing of their orbits ineffective, which preserves the orbital architectures that result from the planet-forming process. Among the measurable properties, the orbital inclination with respect to the stellar rotational axis, stands out as a crucial diagnostic for understanding the migration mechanisms behind the origin of close-in planets. Observational limitations have made the procurement of spin-orbit measurements heavily biased toward hot Jupiter systems. In recent years, however, high-precision spectroscopy has begun to provide obliquity measurements for planets well into the warm Jupiter regime. In this study, we present Rossiter-McLaughlin (RM) measurements of the projected obliquity angle for the warm Jupiter TOI-677 b using ESPRESSO at the VLT. TOI-677 b exhibits an extreme degree of alignment (\\(\\lambda = 0.3 \\pm 1.3\\) deg), which is particularly puzzling given its significant eccentricity (\\(e \\approx 0.45\\)). TOI-677 b thus joins a growing class of close-in giants that exhibit large eccentricities and low spin-orbit angles, which is a configuration not predicted by existing models. We also present the detection of a candidate outer brown dwarf companion on an eccentric, wide orbit (\\(e \\approx 0.4\\) and \\(P \\approx 13\\) yr). Using simple estimates, we show that this companion is unlikely to be the cause of the unusual orbit of TOI-677 b. Therefore, it is essential that future efforts prioritize the acquisition of RM measurements for warm Jupiters.
The evolution of PUCHEROS from a basic to a competitive tool for stellar astrophysics
by
Parra, Manuel
,
Avila, Gerardo
,
Zapata, Abner
in
European Southern Observatory
,
High resolution
,
Radial velocity
2025
We present PUCHEROS +, a new spectrograph developed as an enhanced version of PUCHEROS (Pontificia Universidad Catolica High Echelle Resolution Optical Spectrograph), which was the first high-resolution spectrograph built at the Pontificia Universidad Catolica de Chile (UC). With respect to its predecessor, PUCHEROS + includes a substantial number of improvements, mainly: a new scientific detector, improved objective optics, calibration system, guiding, active thermal control, and remote observing mode. These upgrades convert our early prototype into a much more powerful instrument for science. With a spectral resolution of R = 18000, a spectral range between 400 and 730 nm and an instrument efficiency of about 30 per cent, PUCHEROS + was tested at the ESO (European Southern Observatory) 1.52-m telescope where it has reached a limiting magnitude of about 12 in V band and radial velocity precision of about 30 m/s. The instrument was conceived as a pathfinder for the high-resolution echelle spectrograph PLATOSpec and at the same time, it demonstrates that a compact, relatively low-cost spectrograph can be efficiently employed for long-term monitoring campaigns and as support facility for space missions, in particular if operated remotely at relatively small- or medium-sized telescopes.