Person: Montes Gutiérrez, David
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First Name
David
Last Name
Montes Gutiérrez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
Area
Astronomía y Astrofísica
Identifiers
70 results
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Item Orbital and physical properties of the sigma Ori Aa, Ab, B triple system(Astrophysical journal, 2015) Simón Díaz, S.; Caballero, J. A.; Lorenzo, J.; Maíz Apellániz, J.; Schneider, F. R. N.; Negueruela, I.; Barbá, R. H.; Dorda, R.; Marco, A.; Montes Gutiérrez, David; Pellerin, A.; Sánchez Bermúdez, J.; Sódor, A.; Sota, A.We provide a complete characterization of the astrophysical properties of the sigma Ori Aa, Ab, B hierarchical triple system and an improved set of orbital parameters for the highly eccentric sigma Ori Aa, Ab spectroscopic binary. We compiled a spectroscopic data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filhes method for a detailed orbital analysis of the radial velocity curves and performed a combined quantitative spectroscopic analysis of the sigma Ori Aa, Ab, B system by means of the stellar atmosphere code FASTWIND. We used our own plus other available information on photometry and distance to the system for measuring the radii, luminosities, and spectroscopic masses of the three components. We also inferred evolutionary masses and stellar ages using the Bayesian code BONNSAI. The orbital analysis of the new radial velocity curves led to a very accurate orbital solution of the sigma Ori Aa, Ab pair. We provided indirect arguments indicating that sigma Ori B is a fast-rotating early B dwarf. The FASTWIND+BONNSAI analysis showed that the Aa, Ab pair contains the hottest and most massive components of the triple system while sigma Ori B is a bit cooler and less massive. The derived stellar ages of the inner pair are intriguingly younger than the one widely accepted for the sigma Orionis cluster, at 3 +/- 1 Ma. The outcome of this study will be of key importance for a precise determination of the distance to the s Orionis cluster, the interpretation of the strong X-ray emission detected for sigma Ori Aa, Ab, B, and the investigation of the formation and evolution of multiple massive stellar systems and substellar objects.Item Stars and brown dwarfs in the sigma Orionis cluster IV. IDS/INT and OSIRIS/GTC spectroscopy and Gaia DR2 astrometry(Astronomy and astrophysics, 2019) Caballero, J. A.; Burgos, A. de; Alonso Floriano, F.J.; Cabrera Lavers, A.; García Álvarez, D.; Montes Gutiérrez, DavidContext. Only a few open clusters are as important for the study of stellar and substellar objects, and their formation and evolution, as the young σ Orionis cluster. However, a complete spectroscopic characterisation of its whole stellar population is still missing. Aims. We filled most of that gap with a large spectroscopic and astrometric survey of targets towards σ Orionis. Eventually, it will be one of the open clusters with the lowest proportion of interlopers and the largest proportion of confirmed cluster members with known uncontrovertible youth features. Methods. We acquired 317 low-resolution optical spectra with the Intermediate Dispersion Spectrograph (IDS) at the 2.5 m Isaac Newton Telescope (INT) and the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) at the 10.4 m Gran Telescopio Canarias (GTC). We measured equivalent widths of Li i, Hα, and other key lines from these spectra, and determined spectral types. We complemented this information with Gaia DR2 astrometric data and other features of youth (mid-infrared excess, X-ray emission) compiled with Virtual Observatory tools and from the literature. Results. Of the 168 observed targets, we determined for the first time spectral types of 39 stars and equivalent widths of Li i and Hα of 34 and 12 stars, respectively. We identified 11 close (ρItem No surviving evolved companions of the progenitor of SN 1006(Nature, 2012) González Hernández, Jonay I.; RuizLapuente, Pilar; Tabernero, Hugo M.; Montes Gutiérrez, David; Canal, Ramón; Méndez, Javier; Bedin, Luigi R.Type Ia supernovae are thought to occur when a white dwarf made of carbon and oxygen accretes sufficient mass to trigger a thermonuclear explosion(1). The accretion could be slow, from an unevolved (main-sequence) or evolved (subgiant or giant) star(2,3) (the single-degenerate channel), or rapid, as the primary star breaks up a smaller orbiting white dwarf(3,4) (the double-degenerate channel). A companion star will survive the explosion only in the single-degenerate channel(5). Both channels might contribute to the production of type Ia supernovae(6,7), but the relative proportions of their contributions remain a fundamental puzzle in astronomy. Previous searches for remnant companions have revealed one possible case for SN 1572 (refs 8, 9), although that has been questioned(10). More recently, observations have restricted surviving companions to be small, main-sequence stars(11-13), ruling out giant companions but still allowing the single-degenerate channel. Here we report the results of a search for surviving companions of the progenitor of SN 1006 (ref. 14). None of the stars within 4 arc minutes of the apparent site of the explosion is associated with the supernova remnant, and we can firmly exclude all giant and subgiant stars from being companions of the progenitor. In combination with previous results, our findings indicate that fewer than 20 per cent of type Ia supernovae occur through the single-degenerate channel.Item Effect of magnetic activity saturation in chromospheric flux-flux relationships(Monthly notices of the Royal Astronomical Society, 2011) Martínez Arnáiz, R.; López Santiago, J.; Crespo Chacón, I.; Montes Gutiérrez, DavidWe present a homogeneous study of chromospheric and coronal flux–flux relationships using a sample of 298 late-type dwarf active stars with spectral types F to M. The chromospheric lines were observed simultaneously in each star to avoid spread as a result of long-term variability. Unlike other works, we subtract the basal chromospheric contribution in all the spectral lines studied. For the first time, we quantify the departure of dMe stars from the general relations. We show that dK and dKe stars also deviate from the general trend. Studying the flux–colour diagrams, we demonstrate that the stars deviating from the general relations are those with saturated X-ray emission and we show that these stars also present saturation in the Hα line. Using several age spectral indicators, we show that these are younger stars than those following the general relationships. The non-universality of flux–flux relationships found in this work should be taken into account when converting between fluxes in different chromospheric activity indicators.Item The Gaia-ESO Survey: Chromospheric emission, accretion properties, and rotation in gamma Velorum and Chamaeleon*,**(Astronomy and astrophysics, 2015) Montes Gutiérrez, DavidOne of the goals of the Gaia-ESO Survey (GES), which is conducted with FLAMES at the VLT, is the census and the characterization of the low-mass members of very young clusters and associations. We conduct a comparative study of the main properties of the sources belonging to gamma Velorum (gamma Vel) and Chamaeleon I (Cha I) young associations, focusing on their rotation, chromospheric radiative losses, and accretion. Methods. We used the fundamental parameters (effective temperature, surface gravity, lithium abundance, and radial velocity) delivered by the GES consortium in the first internal data release to select the members of gamma Vel and Cha I among the UVES and GIRAFFE spectroscopic observations. A total of 140 gamma Vel members and 74 Cha I members were studied. The procedure adopted by the GES to derive stellar fundamental parameters also provided measures of the projected rotational velocity (v sin i). We calculated stellar luminosities through spectral energy distributions, while stellar masses were derived by comparison with evolutionary tracks. The spectral subtraction of low-activity and slowly rotating templates, which are rotationally broadened to match the v sin i of the targets, enabled us to measure the equivalent widths (EWs) and the fluxes in the H alpha and H beta lines. The Ha line was also used for identifying accreting objects, on the basis of its EW and the width at the 10% of the line peak (10% W), and for evaluating the mass accretion rate ((M)over dot(acc)). Results. The distribution of v sin i for the members of. Vel displays a peak at about 10 km s(-1) with a tail toward faster rotators. There is also some indication of a different v sin i distribution for the members of its two kinematical populations. Most of these stars have Ha fluxes corresponding to a saturated activity regime. We find a similar distribution, but with a narrower peak, for Cha I. Only a handful of stars in gamma Vel display signatures of accretion, while many more accretors were detected in the younger Cha I, where the highest Ha fluxes are mostly due to accretion, rather than to chromospheric activity. Accreting and active stars occupy two different regions in a T-eff-flux diagram and we propose a criterion for distinguishing them. We derive (M)over dot(acc) in the ranges 10(-11)-10(-9) M-circle dot yr(-1) and 10(-10)-10(-7) M-circle dot yr(-1) for gamma Vel and Cha I accretors, respectively. We find less scatter in the (M)over dot(acc)-M-star relation derived through the H alpha EWs, when compared to the Ha 10% W diagnostics, in agreement with other authors.Item The CARMENES search for exoplanets around M dwarfs Period search in H alpha, Na I D, and Ca II IRT lines(Astronomy and astrophysics, 2019) Cortés Contreras, Miriam; Díez Alonso, Enrique; Montes Gutiérrez, DavidWe use spectra from CARMENES, the Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs, to search for periods in chromospheric indices in 16 M0–M2 dwarfs. We measure spectral indices in the Hα, the Ca II infrared triplet (IRT), and the Na I D lines to study which of these indices are best-suited to finding rotation periods in these stars. Moreover, we test a number of different period-search algorithms, namely the string length method, the phase dispersion minimisation, the generalized Lomb–Scargle periodogram, and the Gaussian process regression with quasi-periodic kernel. We find periods in four stars using Hα and in five stars using the Ca II IRT, two of which have not been found before. Our results show that both Hα and the Ca II IRT lines are well suited for period searches, with the Ca II IRT index performing slightly better than Hα. Unfortunately, the Na I D lines are strongly affected by telluric airglow, and we could not find any rotation period using this index. Further, different definitions of the line indices have no major impact on the results. Comparing the different search methods, the string length method and the phase dispersion minimisation perform worst, while Gaussian process models produce the smallest numbers of false positives and non-detections.ǀItem Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter(Astronomy & Astrophysics, 2010) Martínez Arnáiz, R.; Maldonado, J.; Montes Gutiérrez, David; Eiroa, C.; Montesinos, B.Context. Chromospheric activity produces both photometric and spectroscopic variations that can be mistaken as planets. Large spots crossing the stellar disc can produce planet-like periodic variations in the light curve of a star. These spots clearly affect the spectral line profiles, and their perturbations alter the line centroids creating a radial velocity jitter that might “contaminate” the variations induced by a planet. Precise chromospheric activity measurements are needed to estimate the activity-induced noise that should be expected for a given star. Aims. We obtain precise chromospheric activity measurements and projected rotational velocities for nearby (d ≤ 25 pc) cool (spectral types F to K) stars, to estimate their expected activity-related jitter. As a complementary objective, we attempt to obtain relationships between fluxes in different activity indicator lines, that permit a transformation of traditional activity indicators, i.e., Ca II H & K lines, to others that hold noteworthy advantages. Methods. We used high resolution (~50 000) echelle optical spectra. Standard data reduction was performed using the IRAF ECHELLE package. To determine the chromospheric emission of the stars in the sample, we used the spectral subtraction technique. We measured the equivalent widths of the chromospheric emission lines in the subtracted spectrum and transformed them into fluxes by applying empirical equivalent width and flux relationships. Rotational velocities were determined using the cross-correlation technique. To infer activity-related radial velocity (RV) jitter, we used empirical relationships between this jitter and the R’_HK index. Results. We measured chromospheric activity, as given by different indicators throughout the optical spectra, and projected rotational velocities for 371 nearby cool stars. We have built empirical relationships among the most important chromospheric emission lines. Finally, we used the measured chromospheric activity to estimate the expected RV jitter for the active stars in the sample.Item Calibrating the metallicity of M dwarfs in wide physical binaries with F-, G-, and K-primaries -I: High-resolution spectroscopy with HERMES: stellar parameters, abundances, and kinematics(Monthly notices of the Royal astronomical society, 2018) Montes Gutiérrez, David; González Peinado, R.; Tabernero, H. M.; Caballero, J. A.; Gómez Marfil, Emilio; Alonso Floriano, F. J.; Cortés Contreras, Miriam; González Hernández, J. I.; Klutsch, A.; Moreno Jodar, C.We investigated almost 500 stars distributed among 193 binary or multiple systems made of late-E, G-, or earl y-K-primaries and late-K- or M-dwarf companion candidates, For all of them, we compiled or measured coordinates, J-band magnitudes, spectral types, distances, and proper motions. With these data, we established a sample of 192 physically bound systems. In parallel, we carried out observations with HERMES/Mercator and obtained high-resolution spectra for the 192 primaries and five secondaries. We used these spectra and the automatic STEPAR code for deriving precise stellar atmospheric parameters: T-eff, log g, xi, and chemical abundances for 13 atomic species, including [Fe/H]. After computing Galactocentric space velocities for all the primary stars, we performed a kinematic analysis and classified them in different Galactic populations and stellar kinematic groups of very different ages, which match our own metallicity determinations and isochronal age estimations. In particular, we identified three systems in the halo and 33 systems in the young Local Association, Ursa Major and Castor moving groups, and IC 2391 and Hyades superclusters. We finally studied the exoplanet-metallicity relation in our 193 primaries and made a list 13 M-dwarf companions with very high metallicity that can be the targets of new dedicated exoplanet surveys. All in all, our dataset will be of great help for future works on the accurate determination of metallicity of M dwarfS.Item Herschel discovery of a new class of cold, faint debris discs(Astronomy & Astrophysics, 2011) Montes Gutiérrez, David; otros, ...We present Herschel PACS 100 and 160 μm observations of the solar-type stars α Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel open time key programme (OTKP) DUNES (DUst around NEarby Stars). Our observations show small infrared excesses at 160 μm for all three stars. HD 210277 also shows a small excess at 100 μm, while the 100 μm fluxes of α Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. Both α Men and HD 88230 are spatially resolved in the PACS 160 μm images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from ~115 to ≤ 250 AU. The estimated black body temperatures from the 100 and 160 μm fluxes are ≲22 K, and the fractional luminosity of the cold dust is L_dust/L_⋆ ~ 10^-6, close to the luminosity of the solar-system’s Kuiper belt. These debris discs are the coldest and faintest discs discovered so far around mature stars, so they cannot be explained easily invoking “classical” debris disc models.Item Reaching the boundary between stellar kinematic groups and very wide binaries III. Sixteen new stars and eight new wide systems in the β Pictoris moving group(Astronomy & Astrophysics, 2015) Alonso Floriano, F. J.; Caballero, J. A.; Cortés Contreras, Miriam; Solano, E.; Montes Gutiérrez, DavidAims. We look for common proper motion companions to stars of the nearby young β Pictoris moving group. Methods. First, we compiled a list of 185 β Pictoris members and candidate members from 35 representative works. Next, we used the Aladin and STILTS virtual observatory tools and the PPMXL proper motion and Washington Double Star catalogues to look for companion candidates. The resulting potential companions were subjects of a dedicated astro-photometric follow-up using public data from all-sky surveys. After discarding 67 sources by proper motion and 31 by colour-magnitude diagrams, we obtained a final list of 36 common proper motion systems. The binding energy of two of them is perhaps too small to be considered physically bound. Results. Of the 36 pairs and multiple systems, eight are new, 16 have only one stellar component previously classified as a β Pictoris member, and three have secondaries at or below the hydrogen-burning limit. Sixteen stars are reported here for the first time as moving group members. The unexpected large number of high-order multiple systems, 12 triples and two quadruples among 36 systems, may suggest a biased list of members towards close binaries or an increment of the high-order-multiple fraction for very wide systems.