184 research outputs found
Recurrent Symbiotic Nova T Coronae Borealis Before Outburst
The results of photometric and spectral observations of T CrB obtained in a
wide range of wavelengths in 2011-2023 are presented. We use the near-IR light
curves to determine a new ephemeris for
the times of light minima when the red giant is located between the observer
and the hot component. The flux ratio H/H varied from ~3 to ~8
in 2020-2023, which may be due to a change in the flux ratio between the X-ray
and optical ranges. It is shown that the value of H/H depends on
the rate of accretion onto the hot component of the system. Based on high-speed
follow-up observations obtained on June 8, 2023, we detected a variability of
the HeII line with a characteristic time-scale of ~25 min, the
amplitude of variability in the band was ~0.07. Simulations of the
near-IR light curves accounting for the ellipsoidal effect allowed us to obtain
the parameters of the binary system: the Roche lobe filling factor of the cool
component , the mass ratio , the orbit
inclination . A comparison of the light curve obtained in
2005-2023 with the 1946 outburst template made it possible to predict the date
of the upcoming outburst - January 2024.Comment: 15 pages, 3 tables, 8 figures, submitted to Astronomy Letter
Pharmacotherapy of glaucoma in terms of evidence-based medicine
Glaucoma is a disease associated with increased intraocular pressure (IOP). Of the pharmacological agents for treating glaucoma, there are drugs of the first (most effective and safe) and second-line treatment. First-line treatment includes prostaglandin analogs and beta-blockers. The currently used prostaglandin analogs (latanoprost, bimatoprost, tafluprost and travoprost) are PG F2α analogs that act through stimulation of FP receptors. They are distinguished by the optimal ratio of effectiveness and risk of side effects. They are convenient for the patient because for the therapeutic effect, it is enough to prescribe 1 time per day. As a result, it is rational to start the treatment of glaucoma with a drug in this group. In terms of pharmacoeconomics, the most affordable prostaglandin drug is latanoprost, which is generally as effective as other prostaglandin analogs. β-adrenergic blockers reduce the production of intraocular fluid, the formation of which is controlled by β1- and β2-adrenergic receptors. Therefore, non-selective β-blockers (timolol, levobunolol, metipranolol, and carteolol) have a pharmacodynamic advantage over selective β1-adrenergic antagonists (betaxolol). Conducted clinical studies of β-blockers have shown that given the cost, efficacy and safety, timolol was the most preferable treatment for glaucoma. In the presence of medical contraindications to the use of first-line drugs or to enhance their effectiveness, α2-agonists (apraclonidine and brimonidine), carbonic anhydrase inhibitors (usually local action: dorzolamide and brinzolamide), M-cholinomimetics (pilocarpine, carbachol and echothiopate), and also Rho-kinase inhibitors (ripasudil
TOI-1135 b: A young hot Saturn-size planet orbiting a solar-type star
Despite the thousands of planets in orbit around stars known to date, the
mechanisms of planetary formation, migration, and atmospheric loss remain
unresolved. In this work, we confirm the planetary nature of a young
Saturn-size planet transiting a solar-type star every 8.03 d, TOI-1135\,b. The
age of the parent star is estimated to be in the interval of 125--1000 Myr
based on various activity and age indicators, including its stellar rotation
period of 5.13\,\,0.27 d and the intensity of photospheric lithium. We
obtained follow-up photometry and spectroscopy, including precise radial
velocity measurements using the CARMENES spectrograph, which together with the
TESS data allowed us to fully characterise the parent star and its planet. As
expected for its youth, the star is rather active and shows strong photometric
and spectroscopic variability correlating with its rotation period. We modelled
the stellar variability using Gaussian process regression. We measured the
planetary radius at 9.02\,\,0.23 R (0.81\,\,0.02
R) and determined a 3 upper limit of \,51.4
M (\,0.16 \,M) on the planetary mass by adopting a
circular orbit. Our results indicate that TOI-1135\,b is an inflated planet
less massive than Saturn or Jupiter but with a similar radius, which could be
in the process of losing its atmosphere by photoevaporation. This new young
planet occupies a region of the mass-radius diagram where older planets are
scarse, and it could be very helpful to understanding the lower frequency of
planets with sizes between Neptune and Saturn.Comment: Accepted in A&A. 18 pages, 15 figure
TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf
N.S., R.W. and B.-O.D. acknowledge support from the Swiss National Science Foundation (PP00P2-163967 and PP00P2-190080). M.N.G. acknowledges support from MIT's Kavli Institute as a Juan Carlos Torres Fellow and from the European Space Agency (ESA) as an ESA Research Fellow. A.A.B., B.S.S.and I.A.S. acknowledge the support of the Ministry of Science and Higher Education of the Russian Federation under the grant 075-15-2020-780 (N13.1902.21.0039). L.D. is an F.R.S.-FNRS Postdoctoral Researcher. B.V.R. thanks the Heising-Simons Foundation for support. This publication benefits from the support of the French Community of Belgium in the context of the FRIA Doctoral Grant awarded to M.T. and E.J. acknowledges DGAPA for his postdoctoral fellowship. Y.G.M.C. acknowledges support from UNAM-DGAPA PAPIIT BG-101321. D.D. acknowledges support from the TESS Guest Investigator Program grant 80NSSC19K1727 and NASA Exoplanet Research Program grant 18-2XRP18_2-0136. We acknowledge support from the Centre for Space and Habitability (CSH) of the University of Bern. Part of this work received support from the National Centre for Competence in Research PlanetS, supported by the Swiss National Science Foundation (SNSF). Funding for the TESS mission is provided by NASA's Science Mission Directorate. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This paper includes data collected by the TESS mission that are publicly available from the Mikulski Archive for Space Telescopes (MAST). This work is based upon observations carried out at the Observatorio Astronomico Nacional on the Sierra de San Pedro Martir (OAN-SPM), Baja California, Mexico. We warmly thank the entire technical staff of the Observatorio Astronomico Nacional at San Pedro Martir in Mexico for their unfailing support to SAINT-EX operations, namely: E. Cadena, T. Calvario, E. Colorado, F. Diaz, A. Franco, B. Garcia, C. Guerrero, G. Guisa, F. Guillen, A. Landa, L. Figueroa, B. Hernandez, J. Herrera, E. Lopez, E. Lugo, B. Martinez, G. Melgoza, F. Montalvo, J.M. Nunez, J.L. Ochoa, I. Plauchu, F. Quiroz, H. Riesgo, H. Serrano, T. Verdugo, I. Zavala. The research leading to these results has received funding from the European Research Council (ERC) under the FP/2007-2013 ERC grant agreement nffi 336480, and under the European Union's Horizon 2020 research and innovation programme (grants agreements nffi 679030 and 803193/BEBOP); from an Actions de Recherche Concertee (ARC) grant, financed by the Wallonia-Brussels Federation, from the Balzan Prize Foundation, from the BEL-SPO/BRAIN2.0 research program (PORTAL project), from the Science and Technology Facilities Council (STFC; grant nffi ST/S00193X/1), and from F.R.S-FNRS (Research Project ID T010920F). This work was also partially supported by a grant from the Simons Foundation (PI: Queloz, grant number 327127), as well as by the MERAC foundation (PI: Triaud). PI: Gillon is F.R.S.-FNRS Senior Research Associate.
TRAPPIST is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant PDR T.0120.21, with the participation of the Swiss National Science Fundation (SNF). M.G. and E.J. are F.R.S.-FNRS Senior Research Associate. This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). M.S.I.P. is funded by NSF. Some of the observations in the paper made use of the High-Resolution Imaging instrument(s) `Alopeke (and/or Zorro). `Alopeke (and/or Zorro) was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Data were reduced using a software pipeline originally written by Elliott Horch and Mark Everett. `Alopeke (and/or Zorro) was mounted on the Gemini North (and/or South) telescope of the international Gemini Observatory, a program of NSF's OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation, on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigacion y Desarrollo (Chile), Ministerio de Ciencia, Tecnologia e Innovacion (Argentina), Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This research made use of exoplanet (Foreman-Mackey et al. 2021a,b) and its dependencies (Agol et al. 2020; Kumar et al. 2019; Astropy Collaboration 2013, 2018; Kipping 2013; Luger et al. 2019; Salvatier et al. 2016; Theano Development Team 2016). Additional use of software packages AstroImageJ (Collins et al. 2017) and TAPIR (Jensen 2013).Context. Thanks to the relative ease of finding and characterizing small planets around M-dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current paucity of planets in long-period orbits around M dwarfs makes such objects particularly compelling as they provide clues about the formation and evolution of these systems.
Aims. In this study we present the discovery of TOI-2257 b (TIC 198485881), a long-period (35 d) sub-Neptune orbiting an M3 star at 57.8 pc. Its transit depth is about 0.4%, large enough to be detected with medium-size, ground-based telescopes. The long transit duration suggests the planet is in a highly eccentric orbit (e similar to 0.5), which would make it the most eccentric planet known to be transiting an M-dwarf star.
Methods. We combined TESS and ground-based data obtained with the 1.0-meter SAINT-EX, 0.60-meter TRAPPIST-North, and 1.2-meter FLWO telescopes to find a planetary size of 2.2 R-circle plus and an orbital period of 35.19 days. In addition, we make use of archival data, high-resolution imaging, and vetting packages to support our planetary interpretation.
Results. With its long period and high eccentricity, TOI-2257 b falls into a novel slice of parameter space. Despite the planet's low equilibrium temperature (similar to 256 K), its host star's small size (R-* = 0.311 +/- 0.015) and relative infrared brightness (K-mag = 10.7) make it a suitable candidate for atmospheric exploration via transmission spectroscopy.Swiss National Science Foundation (SNSF)European Commission PP00P2-163967
PP00P2-190080MIT's Kavli InstituteEuropean Space Agency
European CommissionMinistry of Science and Higher Education of the Russian Federation 075-15-2020-780 (N13.1902.21.0039)Heising-Simons FoundationFrench Community of BelgiumDGAPAPrograma de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT)
Universidad Nacional Autonoma de Mexico BG-101321TESS Guest Investigator Program 80NSSC19K1727NASA Exoplanet Research Program 18-2XRP18_2-0136Centre for Space and Habitability (CSH) of the University of BernSwiss National Science Foundation (SNSF)European Research Council (ERC) 336480Actions de Recherche Concertee (ARC) grant - Wallonia-Brussels FederationUK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC)Science and Technology Development Fund (STDF) ST/S00193X/1Fonds de la Recherche Scientifique - FNRS T010920FSimons Foundation 327127MERAC foundationFonds de la Recherche Scientifique - FNRS PDR T.0120.21Swiss National Science Foundation (SNSF)National Science Foundation (NSF)NASA Exoplanet Exploration Program
NASA's Science Mission DirectorateEuropean Research Council (ERC) 679030
803193/BEBOPBalzan Prize Foundation
BEL-SPO/BRAIN2.0 research program (PORTAL project
Simultaneous and panchromatic observations of the fast radio burst FRB 20180916B
Aims. Fast radio bursts are bright radio transients whose origins are not yet understood. The search for a multi-wavelength counterpart of those events can set a tight constraint on the emission mechanism and the progenitor source.Methods. We conducted a multi-wavelength observational campaign on FRB 20180916B between October 2020 and August 2021 over eight activity cycles of the source. Observations were carried out in the radio band by the SRT both at 336 and 1547 MHz and the uGMRT at 400 MHz. Simultaneous observations were conducted by the optical telescopes Asiago (Galileo and Copernico), CMO SAI MSU, CAHA 2.2 m, RTT-150 and TNG, and X/?-ray detectors on board the AGILE, Insight-HXMT, INTEGRAL, and Swift satellites.Results. We present the detection of 14 new radio bursts detected with the SRT at 336 MHz and seven new bursts with the uGMRT from this source. We provide the deepest prompt upper limits in the optical band for FRB 20180916B to date. In fact, the TNG/SiFAP2 observation simultaneous to a burst detection by uGMRT gives an upper limit E-optical/E-radio < 1.3 x 10(2). Another burst detected by the SRT at 336 MHz was also co-observed by Insight-HXMT. The non-detection in the X-rays yields an upper limit (1 - 30 keV band) of EX - ray/E-radio in the range of (0.9 - 1.3) x 10(7), depending on the model that is considered for the X-ray emission
Simultaneous and panchromatic observations of the Fast Radio Burst FRB 20180916B
Aims. Fast Radio Bursts are bright radio transients whose origin has not yet
explained. The search for a multi-wavelength counterpart of those events can
put a tight constrain on the emission mechanism and the progenitor source.
Methods. We conducted a multi-wavelength observational campaign on FRB
20180916B between October 2020 and August 2021 during eight activity cycles of
the source. Observations were led in the radio band by the SRT both at 336 MHz
and 1547 MHz and the uGMRT at 400 MHz. Simultaneous observations have been
conducted by the optical telescopes Asiago (Galileo and Copernico), CMO SAI
MSU, CAHA 2.2m, RTT-150 and TNG, and X/Gamma-ray detectors on board the AGILE,
Insight-HXMT, INTEGRAL and Swift satellites. Results. We present the detection
of 14 new bursts detected with the SRT at 336 MHz and seven new bursts with the
uGMRT from this source. We provide the deepest prompt upper limits in the
optical band fro FRB 20180916B to date. In fact, the TNG/SiFAP2 observation
simultaneous to a burst detection by uGMRT gives an upper limit E_optical /
E_radio < 1.3 x 10^2. Another burst detected by the SRT at 336 MHz was also
co-observed by Insight-HMXT. The non-detection in the X-rays yields an upper
limit (1-30 keV band) of E_X-ray / E_radio in the range of (0.9-1.3) x 10^7,
depending on which model is considered for the X-ray emission.Comment: A&A accepte
TESS Hunt for Young and Maturing Exoplanets (THYME) VII : Membership, rotation, and lithium in the young cluster Group-X and a new young exoplanet
The public, all-sky surveys Gaia and TESS provide the ability to identify new
young associations and determine their ages. These associations enable study of
planetary evolution by providing new opportunities to discover young
exoplanets. A young association was recently identified by Tang et al. and
F{\"u}rnkranz et al. using astrometry from Gaia (called "Group-X" by the
former). In this work, we investigate the age and membership of this
association; and we validate the exoplanet TOI 2048 b, which was identified to
transit a young, late G dwarf in Group-X using photometry from TESS. We first
identified new candidate members of Group-X using Gaia EDR3 data. To infer the
age of the association, we measured rotation periods for candidate members
using TESS data. The clear color--period sequence indicates that the
association is the same age as the Myr-old NGC 3532. We obtained
optical spectra for candidate members that show lithium absorption consistent
with this young age. Further, we serendipitously identify a new, small
association nearby Group-X, which we call MELANGE-2. Lastly, we statistically
validate TOI 2048 b, which is \rearth\ radius planet on a 13.8-day
orbit around its 300 Myr-old host star.Comment: Revised to correct error in reported planet radius (original: 2.1
Earth radii, corrected: 2.6 Earth radii) and units for planetary radius ratio
entries in Table 8. All data tables available open-access with the AJ articl
Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095
The main scientific goal of TESS is to find planets smaller than Neptune
around stars bright enough to allow further characterization studies. Given our
current instrumentation and detection biases, M dwarfs are prime targets to
search for small planets that are in (or nearby) the habitable zone of their
host star. Here we use photometric observations and CARMENES radial velocity
measurements to validate a pair of transiting planet candidates found by TESS.
The data was fitted simultaneously using a Bayesian MCMC procedure taking into
account the stellar variability present in the photometric and spectroscopic
time series. We confirm the planetary origin of the two transiting candidates
orbiting around TOI-2095 (TIC 235678745). The star is a nearby M dwarf ( pc, K, mag) with a
stellar mass and radius of and , respectively. The planetary system is composed of
two transiting planets: TOI-2095b with an orbital period of days and TOI-2095c with days. Both planets have similar sizes with and for planet b and c,
respectively. We put upper limits on the masses of these objects with for the inner and for the outer planet
(95\% confidence level). These two planets present equilibrium temperatures in
the range of 300 - 350 K and are close to the inner edge of the habitable zone
of their star.Comment: Submitted to Astronomy & Astrophysic
The GAPS programme at TNG XLIX. TOI-5398, the youngest compact multi-planet system composed of an inner sub-Neptune and an outer warm Saturn
Short-period giant planets are frequently found to be solitary compared to
other classes of exoplanets. Small inner companions to giant planets with 15 days are known only in five compact systems: WASP-47, Kepler-730,
WASP-132, TOI-1130, and TOI-2000. Here, we report the confirmation of TOI-5398,
the youngest compact multi-planet system composed of a hot sub-Neptune
(TOI-5398 c, = 4.77271 days) orbiting interior to a short-period
Saturn (TOI-5398 b, = 10.590547 days) planet, both transiting
around a 650 150 Myr G-type star. As part of the GAPS Young Object
project, we confirmed and characterised this compact system, measuring the
radius and mass of both planets, thus constraining their bulk composition.
Using multidimensional Gaussian processes, we simultaneously modelled stellar
activity and planetary signals from TESS Sector 48 light curve and our HARPS-N
radial velocity time series. We have confirmed the planetary nature of both
planets, TOI-5398 b and TOI-5398 c, alongside a precise estimation of stellar
parameters. Through the use of astrometric, photometric, and spectroscopic
observations, our findings indicate that TOI-5398 is a young, active G dwarf
star (650 150 Myr), with a rotational period of = 7.34
days. The transit photometry and radial velocity measurements enabled us to
measure both the radius and mass of planets b, ,
, and c, , . TESS observed TOI-5398 during sector 48 and no further
observations are planned in the current Extended Mission, making our
ground-based light curves crucial for ephemeris improvement. With a
Transmission Spectroscopy Metric value of around 300, TOI-5398 b is the most
amenable warm giant (10 < < 100 days) for JWST atmospheric
characterisation.Comment: 29 pages, Paper accepted for publication in Astronomy & Astrophysic
- …