- ID:
- ivo://CDS.VizieR/J/A+A/631/A76
- Title:
- MASCARA-3b radial and light curves
- Short Name:
- J/A+A/631/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of MASCARA-3b, a hot Jupiter orbiting its bright (V=8.33) late F-type host every 5.55149+/-0.00001-days in an almost circular orbit (e=0.050^+0.020^_-0.017_). This is the fourth exoplanet discovered with the Multi-site All-Sky CAmeRA (MASCARA), and the first of these that orbits a late-type star. Follow-up spectroscopic measurements were obtained in and out of transit with the Hertzsprung SONG telescope. Combining the MASCARA photometry and SONG radial velocities reveals a radius and mass of 1.36+/-0.05R_Jup_ and 4.2+/-0.2M_Jup_. In addition, SONG spectroscopic transit observations were obtained on two separate nights. From analyzing the mean out-of-transit broadening function, we obtain vsini*=20.4+/-0.4km/s. In addition, investigating the Rossiter-McLaughlin effect, as observed in the distortion of the stellar lines directly and through velocity anoma lies, we find the projected obliquity to be {lambda}=1.2^+8.2^_-7.4_deg, which is consistent with alignment.
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- ID:
- ivo://CDS.VizieR/J/A+A/628/A9
- Title:
- MASCARA-2b transmission spectra
- Short Name:
- J/A+A/628/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ultra-hot Jupiters orbit very close to their host star and consequently receive strong irradiation, causing their atmospheric chemistry to be different from the common gas giants. Here, we have studied the atmosphere of one of these particular hot planets, MASCARA- 2b/KELT-20b, using four transit observations with high resolution spectroscopy facilities. Three of these observations were performed with HARPS-N and one with CARMENES. Additionally, we simultaneously observed one of the transits with MuSCAT2 to monitor possible spots in the stellar surface. At high resolution, the transmission residuals show the effects of Rossiter-McLaughlin and centre- to-limb variations from the stellar lines profiles, which we have corrected to finally extract the transmission spectra of the planet. We clearly observe the absorption features of CaII, FeII, NaI, H{alpha}, and H{beta} in the atmosphere of MASCARA-2b, and indications of H{gamma} and MgI at low signal-to-noise ratio. In the case of NaI, the true absorption is difficult to disentangle from the strong telluric and interstellar contamination. The results obtained with CARMENES and HARPS-N are consistent, measuring an H{alpha} absorption depth of 0.68+/-0.05 and 0.59+/-0.07%, and NaI absorption of 0.11+/-0.04 and 0.09+/-0.05% for a 0.75{AA} passband, in the two instruments respectively. The H{alpha} absorption corresponds to ~1.2Rp, which implies an expanded atmosphere, as a result of the gas heating caused by the irradiation received from the host star. For H{beta} and H{gamma} only HARPS-N covers this wavelength range, measuring an absorption depth of 0.28+/-0.06 and 0.21+/-0.07%, respectively. For CaII, only CARMENES covers this wavelength range measuring an absorption depth of 0.28+/-0.05, 0.41+/-0.05 and 0.27+/-0.06% for CaII {lambda}8498{AA}, {lambda}8542{AA} and {lambda}8662{AA} lines, respectively. Three additional absorption lines of FeII are observed in the transmission spectrum by HARPS-N (partially covered by CARMENES), measuring an average absorption depth of 0.08+/-0.04% (0.75{AA} passband). The results presented here are consistent with theoretical models of ultra-hot Jupiters atmospheres, suggesting the emergence of an ionised gas on the day-side of such planets. Calcium and iron, together with other elements, are expected to be singly ionised at these temperatures and be more numerous than its neutral state. The Calcium triplet lines are detected here for the first time in transmission in an exoplanet atmosphere. Description: The transmission spectra and of MASCARA-2b/KELT-20b are presented. Three transits with HARPS-North at TNG telescope were retrieved and one transit with CARMENES at 3.5 telescope at CAHA Observatory. For each spectral line the transmission spectra of MASCARA-2b/KELT-20b after correcting the CLV + RME are presented here. We note that in some cases the transmission spectrum of a specific line also includes transmission lines located close to the main spectral line (e.g. in case of NaI doublet). However, it is important to note that only the main spectral line of each file (see files name) includes the CLV+RME corrections. You need to work with specific files.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A78
- Title:
- Masses and ages of 1059 HARPS-GTO stars
- Short Name:
- J/A+A/624/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The purpose of this work is to evaluate how several elements produced by different nucleosynthesis processes behave with stellar age and provide empirical relations to derive stellar ages from chemical abundances. We derived different sets of ages using Padova and Yonsei-Yale isochrones and Hipparcos and Gaia parallaxes for a sample of more than 1000 FGK dwarf stars for which he have high-resolution R~115000 and high-quality spectra from the HARPS-GTO program. We analyzed the temporal evolution of different abundance ratios to find the best chemical clocks. We applied multivariable linear regressions to our sample of stars with a small uncertainty on age to obtain empirical relations of age as a function of stellar parameters and different chemical clocks. We find that [alpha/Fe] ratio (average of Mg, Si, and Ti), [O/Fe] and [Zn/Fe] are good age proxies with a lower dispersion than the age-metallicity dispersion. Several abundance ratios present a significant correlation with age for chemically separated thin disk stars (i.e., low-alpha) but in the case of the chemically defined thick disk stars (i.e., high-alpha) only the elements Mg, Si, Ca, and TiII show a clear correlation with age. We find that the thick disk stars are more enriched in light-s elements than thin disk stars of similar age. The maximum enrichment of s-process elements in the thin disk occurs in the youngest stars which in turn have solar metallicity. The slopes of the [X/Fe]-age relations are quite constant for O, Mg, Si, Ti, Zn, Sr, and Eu regardless of the metallicity. However, this is not the case for Al, Ca, Cu and most of the s-process elements, which display very different trends depending on the metallicity. This demonstrates the limitations of using simple linear relations based on certain abundance ratios to obtain ages for stars of different metallicities. Finally, we show that by using 3D relations with a chemical clock and two stellar parameters (either Teff, [Fe/H] or stellar mass) we can explain up to 89% of age variance in a star. A similar result is obtained when using 2D relations with a chemical clock and one stellar parameter, explaining up to a 87% of the variance. The complete understanding of how the chemical elements were produced and evolved in the Galaxy requires the knowledge of stellar ages and precise chemical abundances. We show how the temporal evolution of some chemical species change with metallicity, with remarkable variations at super-solar metallicities, which will help to better constrain the yields of different nucleosynthesis processes along the history of the Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/709/535
- Title:
- Masses and radii of eclipsing binaries
- Short Name:
- J/ApJ/709/535
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The currently favored method for estimating radii and other parameters of transiting-planet host stars is to match theoretical models to observations of the stellar mean density {rho}_*_, the effective temperature T_eff_, and the composition parameter [Z]. This explicitly model-dependent approach is based on readily available observations, and results in small formal errors. Its performance will be central to the reliability of results from ground-based transit surveys such as TrES, HAT, and SuperWASP, as well as to the space-borne missions MOST, CoRoT, and Kepler. Here, I use two calibration samples of stars (eclipsing binaries (EBs) and stars for which asteroseismic analyses are available) having well-determined masses and radii to estimate the accuracy and systematic errors inherent in the {rho}_*_ method. When matching to the Yonsei-Yale stellar evolution models, I find the most important systematic error results from selection bias favoring rapidly rotating (hence probably magnetically active) stars among the EB sample. If unaccounted for, this bias leads to a mass-dependent underestimate of stellar radii by as much as 4% for stars of 0.4M_{sun}_, decreasing to zero for masses above about 1.4M_{sun}_. Relative errors in estimated stellar masses are three times larger than those in radii.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A74
- Title:
- Massive binaries in Cepheus OB2/3 region
- Short Name:
- J/A+A/538/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two different formation scenarios for stars of masses larger than 10M_{sun}_ exist. Although simulations within both scenarios are capable of producing stars up to the highest observed masses, the relevance of the two formation scenarios for massive star-formation is not yet clear. We aim to detect companions to massive stars to constrain the binary parameters of the multiple systems. These findings will help to constrain the formation of massive stars.
- ID:
- ivo://CDS.VizieR/J/AJ/149/26
- Title:
- Massive binary stars from an HST/FGS survey
- Short Name:
- J/AJ/149/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an all-sky survey made with the Fine Guidance Sensor on the Hubble Space Telescope to search for angularly resolved binary systems among massive stars. The sample of 224 stars is comprised mainly of Galactic O- and B-type stars and luminous blue variables, plus a few luminous stars in the Large Magellanic Cloud. The FGS TRANS mode observations are sensitive to the detection of companions with an angular separation between 0.01'' and 1.0'' and brighter than {delta}m=5. The FGS observations resolved 52 binary and 6 triple star systems and detected partially resolved binaries in 7 additional targets (43 of these are new detections). These numbers yield a companion detection frequency of 29% for the FGS survey. We also gathered literature results on the numbers of close spectroscopic binaries and wider astrometric binaries among the sample, and we present estimates of the frequency of multiple systems and the companion frequency for subsets of stars residing in clusters and associations, field stars, and runaway stars. These results confirm the high multiplicity fraction, especially among massive stars in clusters and associations. We show that the period distribution is approximately flat in increments of logP. We identify a number of systems of potential interest for long-term orbital determinations, and we note the importance of some of these companions for the interpretation of the radial velocities and light curves of close binaries that have third companions.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A125
- Title:
- 54 massive companions detected with SOPHIE
- Short Name:
- J/A+A/631/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Brown-dwarfs (BD) are substellar objects with masses intermediate between planets and stars within about 13-80M_J_. While isolated brown-dwarfs are most likely produced by gravitational collapse in molecular clouds down to masses of a few M_J_, a nonnegligible fraction of low-mass companions might be formed through the planet formation channel in protoplanetary disks. The upper mass limit of objects formed within disks is still observationnally unknown, the main reason being the strong dearth of BD companions at orbital periods shorter than 10 years, a.k.a. the brown-dwarf desert. We aim at determining the best statistics of secondary companions within the 10-100M_Jup_ range within 10au from the primary star, while minimising observational bias. This can help determining the mass limit separating planet-formed from star-formed browndwarfs. Moreover, the exact shape of the BD desert in a mass-period space is still underdetermined, and can strongly constrain the companion-star interactions mechanisms at work in close binary systems at small mass ratio. We made an extensive use of the radial velocity (RV) surveys of FGK stars below 60 pc distance to the Sun and in the northern hemisphere performed with the SOPHIE spectrograph at Observatoire de Haute-Provence. We derived the Keplerian solutions of the RV variations of 54 sources. Public astrometric data of the Hipparcos and Gaia missions allowed deriving direct astrometric solution of orbital motion and constraining the mass of the companion for most sources. We introduce GASTON, a new method to derive inclination combining RVs Keplerian and astrometric excess noise from Gaia DR1. We report the discovery of 12 new BD candidates. For 5 of them, additional astrometric data led to revise their mass in the M-dwarf regime. Among the 7 remaining objects, 4 are confirmed BD companions, and 3 others are likely also in this mass regime. Moreover, we report the detection of 42 objects in the M-dwarf mass regime 90M_J_-0.52M_{sun}_. The resulting Msin i-P distribution of BD candidates shows a clear drop in the detection rate below 80-day orbital period. Above that limit, the BD desert reveals rather wet, with a uniform distribution of the Msin i. We derive a minimum BD-detection frequency around Solar-like stars of 2.0+/-0.5%.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A66
- Title:
- Massive runaway and walkaway stars models
- Short Name:
- J/A+A/624/A66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform an extensive numerical study of the evolution of massive binary systems to predict the peculiar velocities that stars obtain when their companion collapses and disrupts the system. Our aim is to (i) identify which predictions are robust against model uncertainties and assess their implications, (ii) investigate which physical processes leave a clear imprint and may, therefore, be constrained observationally and (iii) provide a suite of publicly available model predictions, to allow for the use of kinematic constraints from the Gaia mission. We find that 22^+26^_-8_% of all massive binary systems merge prior to the first core-collapse in the system. Of the remainder, 86^+11^_-9_% become unbound because of the core-collapse. Remarkably, this rarely produce runaway stars (observationally defined as stars with velocities above 30km/s). These are outnumbered by more than an order of magnitude by slower unbound companions, or "walkaway stars". This is a robust outcome of our simulations and is due to the reversal of the mass ratio prior to the explosion and widening of the orbit, as we show analytically and numerically. For stars more massive than 15M_{sun}_, we estimate that 10^+5^_-8_% are walkaways and only 0.5^+1.0^_-0.4_% are runaways, nearly all of which have accreted mass from their companion. Our findings are consistent with earlier studies, however, the low runaway fraction we find is in tension with observed fractions of about 10%. Thus, astrometric data on presently single massive stars can potentially constrain the physics of massive binary evolution. Finally, we show that the high end of the mass distributions of runaway stars is very sensitive to the assumed black hole natal kicks and propose this as a potentially stringent test for the explosion mechanism. We also discuss companions remaining bound which can evolve into X-ray and gravitational wave sources.
- ID:
- ivo://CDS.VizieR/J/A+A/527/A140
- Title:
- Mass limits on substellar companions
- Short Name:
- J/A+A/527/A140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The recently completed re-reduction of the Hipparcos data by van Leeuwen (2007, Astrophys. Space Library 350) makes it possible to search for the astrometric signatures of planets and brown dwarfs known from radial velocity surveys in the improved Hipparcos intermediate astrometric data. Our aim is to put more significant constraints on the orbital parameters which cannot be derived from radial velocities alone, i.e. the inclination and the longitude of the ascending node, than was possible before. The determination of the inclination in particular allows to calculate an unambiguous companion mass, rather than the lower mass limit which can be obtained from radial velocity measurements.
- ID:
- ivo://CDS.VizieR/J/AJ/106/773
- Title:
- Mass-luminosity relation
- Short Name:
- J/AJ/106/773
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mass-luminosity relations determined at infrared wavelengths are presented for stars with masses 1.0 to 0.08 solar masses. Using infrared speckle imaging techniques on a sample of nearby binaries, we have been able to concentrate on the lower main sequence (Mass<=0.5M_sun_), for which an accurate mass-luminosity calibration has remained problematic. In addition, the mass-visual luminosity relation for stars with 2.0>=Mass>=0.08M_sun_ is produced by implementing new photometric relations linking V to JHK wavelengths for the nearby stars, supplemented with eclipsing binary information. These relations predict that objects with masses ~0.08 solar masses have M(K)~=10 and M(V)~=18.
