Persona: HERRERA HERNÁNDEZ, ALEJANDRO
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HERRERA HERNÁNDEZ
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ALEJANDRO
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Publicación Acceso Abierto TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis(EDP Sciences, 2021-01-15) Parviainen, H.; Pallé, E.; Zapatero Osorio, M. R.; Nowak, G.; Fukui, A.; Murgas Alcaino, F.; Narita, N.; Stassun, K. G.; Livingston, J. H.; Collins, K. A.; Hidalgo Soto, D.; Béjar, V. J. S.; Korth, J.; Monelli, M.; Montañés Rodríguez, P.; Casasayas Barris, N.; Chen, G.; Crouzet, N.; De Leon, J. P.; Kawauchi, K.; Klagyivik, P.; Kusakabe, N.; Luque, R.; Mori, M.; Nishiumi, T.; Prieto Arranz, J.; Tamura, M.; Watanabe, N.; Gan, T.; Collins, K. I.; Jensen, E. L. N.; Barclay, T.; Doty, J. P.; Jenkins, J. M.; Latham, D. W.; Paegert, M.; Ricker, G.; Rodríguez, D. R.; Seager, S.; Shporer, A.; Vanderspek, R.; Villaseñor, J. N.; Winn, J. N.; Wohler, B.; Wong, I.; HERRERA HERNÁNDEZ, ALEJANDRO; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Japan Society for the Promotion of Science (JSPS); Deutsche Forschungsgemeinschaft (DFG); Monelli, M. [0000-0001-5292-6380]; Collins, K. [0000-0003-2781-3207]; Paegert, M. [0000-0001-8120-7457]; Luque, R. [0000-0002-4671-2957]Context. We report the discovery of TOI-519 b (TIC 218795833), a transiting substellar object (R = 1.07 RJup) orbiting a faint M dwarf (V = 17.35) on a 1.26 d orbit. Brown dwarfs and massive planets orbiting M dwarfs on short-period orbits are rare, but more have already been discovered than expected from planet formation models. TOI-519 is a valuable addition to this group of unlikely systems, and it adds towards our understanding of the boundaries of planet formation. Aims. We set out to determine the nature of the Transiting Exoplanet Survey Satellite (TESS) object of interest TOI-519 b. Methods. Our analysis uses a SPOC-pipeline TESS light curve from Sector 7, multicolour transit photometry observed with MuSCAT2 and MuSCAT, and transit photometry observed with the LCOGT telescopes. We estimated the radius of the transiting object using multicolour transit modelling, and we set upper limits for its mass, effective temperature, and Bond albedo using a phase curve model that includes Doppler boosting, ellipsoidal variations, thermal emission, and reflected light components. Results. TOI-519 b is a substellar object with a radius posterior median of 1.07 RJup and 5th and 95th percentiles of 0.66 and 1.20 RJup, respectively, where most of the uncertainty comes from the uncertainty in the stellar radius. The phase curve analysis sets an upper effective temperature limit of 1800 K, an upper Bond albedo limit of 0.49, and a companion mass upper limit of 14 MJup. The companion radius estimate combined with the Teff and mass limits suggests that the companion is more likely a planet than a brown dwarf, but a brown-dwarf scenario is a priori more likely given the lack of known massive planets in ≈ 1 day orbits around M dwarfs with Teff < 3800 K, and given the existence of some (but few) brown dwarfs.Publicación Restringido Systematic isotopic marking of polymeric components for in-situ space missions(Elsevier BV, 2020-02-01) Mora, J.; García Sancho, Amador; Alonso, R.; Atienza, R.; López Reyes, G.; Sanz Arranz, A.; HERRERA HERNÁNDEZ, ALEJANDRO; López Reyes, G. [0000-0003-1005-1760]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737In the last decades, together with the technological advances, the exploration of closer celestial bodies has experimented a high increasing, with a special relevance of the missions whose objective is the scientific search of life precursors. Since the birth of COSPAR (Committee on space research) in 1964, many advances have been achieved in terms of Planetary Protection, to avoid introducing terrestrial contamination in other systems, and/or come back with extraterrestrial contaminations in sample return missions. Many restrictive protocols are adopted by space missions to minimize the bacteriological, molecular and particle contaminations, and especially harder in scientific missions, where the risk of a false positive in an analysis due to terrestrial contamination is critical. These missions search for small quantities of organic material, and any trace of simple signals of C–H, C–O, C–C, C–N, etc. bonds are the target. Many of these signals are present in all the polymeric components used in a space vehicle, and any accidental or natural contamination could lead to a false positive detection of precursors of life. In this work, a new protected technology to avoid any doubt in these cases is proposed: the systematic isotopic marking of polymeric materials used in space missions. As proof of concept, polyethylene terephthalate (PET) polymers, with the same characteristics of the one used in the calibration target for the Raman Laser Spectrometer (RLS) in the ExoMars mission, were synthetized in three different ratios of deuterium marking: 0%, 35%, and 100%. In addition the calibration target of the SuperCam instrument of the Mars 2020 mission also includes a sample of PET. The polymeric characterization by Thermo-gravimetric analysis (TGA) and Differential scanning calorimetry (DSC) showed similar characteristics, in the range of commercial PET polymers. The same analytical techniques used for organic studies, on board of the ExoMars laboratory, were used for this study: Raman spectroscopy, and Gas chromatography with mass spectrometry (GC/MS). Results showed that both marked compositions could be unequivocally identified, due to the expected differences caused by the increasing of mass of the marked hydrogen atoms. The materials were subjected to the outgassing test, according to ECSS-Q-ST-70-02C standard, of mandatory compliance for every material used in a space mission following the European standards ECSS, to test the validity for space use. All materials, marked and unmarked, passed this test, and even a slight improvement in RML could be observed in the fully deuterium marked (100%) PET, probably caused by its higher weight, but further studies are needed to verify this trend.Publicación Acceso Abierto MuSCAT2 multicolour validation of TESS candidates: an ultra-short-period substellar object around an M dwarf(EDP Sciences, 2020-01-03) Parviainen, H.; Pallé, E.; Zapatero Osorio, M. R.; Montañés Rodríguez, P.; Murgas Alcaino, F.; Narita, N.; Hidalgo Soto, D.; Béjar, V. J. S.; Korth, J.; Monelli, M.; Casasayas Barris, N.; Crouzet, N.; De Leon, J. P.; Fukui, A.; Klagyivik, P.; Kusakabe, N.; Luque, R.; Mori, M.; Nishiumi, T.; Prieto Arranz, J.; Tamura, M.; Watanabe, N.; Burke, C. J.; Charbonneau, D.; Collins, K. A.; Collins, K. I.; Conti, D.; García Soto, A.; Jenkins, J. S.; Jenkins, J. M.; Levine, A.; Li, J.; Rinehart, S.; Seager, S.; Tenenbaum, P.; Ting, E. B.; Vanderspek, R.; Vezie, M.; Winn, J. N.; HERRERA HERNÁNDEZ, ALEJANDRO; Ministerio de Economía y Competitividad (MINECO); Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); Japan Society for the Promotion of Science (JSPS); Japan Science and Technology Agency (JST); Parvianen, H. [0000-0001-5519-1391]; Monelli, M. [0000-0001-5292-6380]; Korth, J. [0000-0002-0076-6239]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Luque, R. [0000-0002-4671-2957]; Kusakabe, N. [0000-0001-9194-1268]; Collins, K. [0000-0003-2781-3207]; García Soto, A. [0000-0001-9828-3229]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Context. We report the discovery of TOI 263.01 (TIC 120916706), a transiting substellar object (R = 0.87 RJup) orbiting a faint M3.5 V dwarf (V = 18.97) on a 0.56 d orbit. Aims. We setout to determine the nature of the Transiting Exoplanet Survey Satellite (TESS) planet candidate TOI 263.01 using ground-based multicolour transit photometry. The host star is faint, which makes radial-velocity confirmation challenging, but the large transit depth makes the candidate suitable for validation through multicolour photometry. Methods. Our analysis combines three transits observed simultaneously in r′, i′, and zs bands usingthe MuSCAT2 multicolour imager, three LCOGT-observed transit light curves in g′, r′, and i′ bands, a TESS light curve from Sector 3, and a low-resolution spectrum for stellar characterisation observed with the ALFOSC spectrograph. We modelled the light curves with PYTRANSIT using a transit model that includes a physics-based light contamination component, allowing us to estimate the contamination from unresolved sources from the multicolour photometry. Using this information we were able to derive the true planet–star radius ratio marginalised over the contamination allowed by the photometry.Combining this with the stellar radius, we were able to make a reliable estimate of the absolute radius of the object. Results. The ground-based photometry strongly excludes contamination from unresolved sources with a significant colour difference to TOI 263. Furthermore, contamination from sources of the same stellar type as the host is constrained to levels where the true radius ratio posterior has a median of 0.217 and a 99 percentile of0.286. The median and maximum radius ratios correspond to absolute planet radii of 0.87 and 1.41 RJup, respectively,which confirms the substellar nature of the planet candidate. The object is either a giant planetor a brown dwarf (BD) located deep inside the so-called “brown dwarf desert”. Both possibilities offer a challenge to current planet/BD formation models and make TOI 263.01 an object that merits in-depth follow-up studies.
