20 research outputs found
The CORALIE survey for southern extrasolar planets XIX. Brown dwarfs and stellar companions unveiled by radial velocity and astrometry
A historical planet-search on a sample of 1647 nearby southern main sequence
stars has been ongoing since 1998 with the CORALIE spectrograph at La Silla
Observatory, with a backup subprogram dedicated to the monitoring of binary
stars. We review 25 years of CORALIE measurements and search for Doppler
signals consistent with stellar or brown dwarf companions to produce an updated
catalog of both known and previously unpublished binary stars in the
planet-search sample, assessing the binarity fraction of the stellar population
and providing perspective for more precise planet-search in the binary sample.
We perform new analysis on the CORALIE planet-search sample radial velocity
measurements, searching for stellar companions and obtaining orbital solutions
for both known and new binary systems. We perform simultaneous radial velocity
and proper motion anomaly fits on the subset of these systems for which
Hipparcos and Gaia astrometry measurements are available, obtaining accurate
estimates of true mass for the companions. We find 218 stars in the CORALIE
sample to have at least one stellar companion, 130 of which are not yet
published in the literature and for which we present orbital solutions. The use
of proper motion anomaly allow us to derive true masses for the stellar
companions in 132 systems, which we additionally use to estimate stability
regions for possible planetary companions on circumprimary or circumbinary
orbits. Finally, we produce detection limit maps for each star in the sample
and obtain occurrence rates of and
for brown dwarf and stellar companions respectively
in the CORALIE sample.Comment: 34 pages, 15 figures, accepted for publication in A&
Two long-period transiting exoplanets on eccentric orbits: NGTS-20 b (TOI-5152 b) and TOI-5153 b
Long-period transiting planets provide the opportunity to better understand
the formation and evolution of planetary systems. Their atmospheric properties
remain largely unaltered by tidal or radiative effects of the host star, and
their orbital arrangement reflects a different, and less extreme, migrational
history compared to close-in objects. The sample of long-period exoplanets with
well determined masses and radii is still limited, but a growing number of
long-period objects reveal themselves in the TESS data. Our goal is to vet and
confirm single transit planet candidates detected in the TESS space-based
photometric data through spectroscopic and photometric follow up observations
with ground-based instruments. We use the Next Generation Transit Survey (NGTS)
to photometrically monitor the candidates in order to observe additional
transits. We report the discovery of two massive, warm Jupiter-size planets,
one orbiting the F8-type star TOI-5153 and the other orbiting the G1-type star
NGTS-20 (=TOI-5152). From our spectroscopic analysis, both stars are metal-rich
with a metallicity of 0.12 and 0.15, respectively. Follow-up radial velocity
observations were carried out with CORALIE, CHIRON, FEROS, and HARPS. TOI-5153
hosts a 20.33 day period planet with a planetary mass of 3.26 (+-0.18) Mj, a
radius of 1.06 (+-0.04) Rj , and an orbital eccentricity of 0.091 (+-0.026).
NGTS-20 b is a 2.98 (+-0.16) Mj planet with a radius of 1.07 (+-0.04) Rj on an
eccentric (0.432 +- 0.023) orbit with an orbital period of 54.19 days. Both
planets are metal-enriched and their heavy element content is in line with the
previously reported mass-metallicity relation for gas giants. Both warm
Jupiters orbit moderately bright host stars making these objects valuable
targets for follow-up studies of the planetary atmosphere and measurement of
the spin-orbit angle of the system.Comment: 17 pages, 13 figures, accepted to A&
Three long period transiting giant planets from TESS
We report the discovery and orbital characterization of three new transiting
warm giant planets. These systems were initially identified as presenting
single transit events in the light curves generated from the full frame images
of the Transiting Exoplanet Survey Satellite (TESS). Follow-up radial velocity
measurements and additional light curves were used to determine the orbital
periods and confirm the planetary nature of the candidates. The planets orbit
slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has
a mass of = 0.30 0.04 , a radius of = 1.00 0.02
, and a low eccentricity orbit (e=0.15 0.05) with a period of P=
30.08364 0.00005 d . TOI 2338b has a mass of = 5.98 0.20
, a radius of = 1.00 0.01 , and a highly eccentric orbit (e=
0.676 0.002 ) with a period of P= 22.65398 0.00002 d . Finally, TOI
2589b has a mass of = 3.50 0.10 , a radius of = 1.08
0.03 , and an eccentric orbit (e = 0.522 0.006 ) with a
period of P= 61.6277 0.0002 d . TOI 4406b and TOI 2338b are enriched in
metals compared to their host stars, while the structure of TOI 2589b is
consistent with having similar metal enrichment to its host star.Comment: 24 pages, 16 figures, accepted in A
TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars From The Full-Frame Images
We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA\u27s Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP = 1.01–1.77 RJ) and have masses that range from 0.85 to 6.33 MJ. The host stars of these systems have F and G spectral types (5595 ≤ Teff ≤ 6460 K) and are all relatively bright (9.5 \u3c V \u3c 10.8, 8.2 \u3c K \u3c 9.3), making them well suited for future detailed characterization efforts. Three of the systems in our sample (TOI-640 b, TOI-1333 b, and TOI-1601 b) orbit subgiant host stars ( g \u3c 4.1). TOI-640 b is one of only three known hot Jupiters to have a highly inflated radius (RP \u3e 1.7 RJ, possibly a result of its host star\u27s evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of MJ and a statistically significant, nonzero orbital eccentricity of e = . This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P = 10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA\u27s TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals
TRAPPIST Habitable Atmosphere Intercomparison (THAI) workshop report
This is the final version. Available on open access from IOP Publishing via the DOI in this recordThe era of atmospheric characterization of terrestrial exoplanets is just around the corner. Modeling prior to observations is crucial in order to predict the observational challenges and to prepare for the data interpretation. This paper presents the report of the TRAPPIST Habitable Atmosphere Intercomparison (THAI) workshop (14-16 September 2020). A review of the climate models and parameterizations of the atmospheric processes on terrestrial exoplanets, model advancements and limitations, as well as direction for future model development was discussed. We hope that this report will be used as a roadmap for future numerical simulations of exoplanet atmospheres and maintaining strong connections to the astronomical community
TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images
We present the discovery and characterization of five hot and warm Jupiters - TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960) - based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (R P = 1.01-1.77 R J) and have masses that range from 0.85 to 6.33 M J. The host stars of these systems have F and G spectral types (5595 ≤ T eff ≤ 6460 K) and are all relatively bright (9.5 1.7 R J, possibly a result of its host star's evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of 6.31-0.30+0.28 M J and a statistically significant, nonzero orbital eccentricity of e = 0.074-0.022+0.021. This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P = 10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA's TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals
TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images
We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP = 1.01–1.77 RJ) and have masses that range from 0.85 to 6.33 MJ. The host stars of these systems have F and G spectral types (5595 ≤ Teff ≤ 6460 K) and are all relatively bright (9.5 1.7 RJ, possibly a result of its host star's evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of MJ and a statistically significant, nonzero orbital eccentricity of e = . This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P = 10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA's TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals
Comportement en vapocraquage de molécules modèles et de distillats sous vide hydrotraités. Deuxième partie : pyrolyse de molécules modèles représentatives des distillats sous vide bruts et hydrotraités
La pyrolyse de molécules modèles a permis sur la base d'écarts de rendements obtenus entre le n -décane et leur mélange à 20 % avec celui-ci, l'établissement d'une échelle de potentialité de craquage présentée précédemment. L'approche des phénomènes de pyrolyse par des schémas réactionnels simplifiés est développée dans le présent article pour des molécules modèles, exemples de chaque grande famille susceptible de constituer le distillat sous vide : le perhydrophénanthrène pour les naphtènes lourds, l'octahydrophénanthrène symétrique pour les naphténoaromatiques, le naphtalène et l'alpha méthylnaphtalène pour les aromatiques méthylés ou non, le dodécylbenzène pour les aromatiques substitués par une longue chaîne aliphatique. Le cas de l'acénaphtylène a été examiné à part
Comportement en vapocraquage de molécules modèles et de distillats sous vide hydrotraités. Première partie : potentialité de craquage, réacteur à profil de température rectangulaire et à court temps de séjour Steam-Cracking Behavior of Model Molecules and Hydrotreated Vacuum Distillates
Dans le cadre de la valorisation des coupes lourdes par vapocraquage, des distillats sous vide plus ou moins hydrotraités et des molécules modèles ont été pyrolysés. Cette étude a été réalisée sur un micropilote dont la partie réactionnelle est chauffée entre 680 et 860°C, par induction électromagnétique haute fréquence; le débit total peut varier de 60 à 800 g/h avec une perte de charge inférieure à 0,3 bar. Deux réacteurs tubulaires spiralés de rapport surface/volume allant jusqu'à 2000 m-1 permettent d'atteindre des temps de séjour de 10 à 400 millisecondes. Un indice quantifiant l'aptitude de chaque molécule à produire de l'éthylène, du propylène et des composés lourds, a permis l'établissement d'une échelle de potentialité de craquage, permettant d'orienter les performances d'un catalyseur de prétraitement : optimisation de la consommation d'hydrogène, meilleure valorisation des charges lourdes lors du vapocraquage. Grâce au profil de température rectangulaire du micropilote, des gains très importants de rendements d'éthylène et une production très faible d'asphaltènes ont été mis en évidence par pyrolyse de distillats sous vide hydrotraités. L'importance primordiale de la température dans le couple température-temps de séjour a été confirmée. Within the framework of the upgrading of heavy cuts for steam cracking, more or less hydrotreated vacuum distillates and model molecules were pyrolyzed. This research was done in a micropilot plant in which the reaction section was heated to between 680 and 860°C by high-frequency electromagnetic induction. The total flow rate can vary from 60 to 800 g/h with a pressure drop of less than 0. 3 bar. Two spiral tubular reactors with a high surface/volume ratio of up to 2000 m-1 enable residence times of 10 to 400 milliseconds to be obtained. An index quantifying the capacity of each molecule to produce ethylene, propylene and heavy compounds was used to determine a scale of cracking potential, so that the performances of a pretreatment catalyst could be oriented, i. e. optimization of hydrogen consumption and better upgrading of heavy feedstocks during steam cracking. Thanks to the rectangular temperature profile of the micropilot plant, very great improvements in ethylene production and very low asphaltene production were revealed by the pyrolysis of hydrotreated vacuum distillates. The primordial importance of temperature in the temperature/residence-time pair was confirmed