Abstract
The scope of this article is to analyze the behavior of children’s brain waves in response to interaction with an augmented reality application that aims to support the concept of ...measurement in physics teaching. In particular, the analysis of brain waves is carried out through a brain-computer interface that measures 6 cognitive states such as engagement, interest, stress, focus, excitation, and relaxation. The method used to perform the analysis is carried out by means of electroencephalography, which is an electrophysiological process to record the electrical activity of the brain, and which is captured by means of sensors located on the scalp. Once the signals are captured, they are amplified, digitized, and stored in a computer for processing and analysis. Initially, electrical signals are recorded in response to a measurement stimulus with traditional methods and later with an augmented reality application stimulus. Among the most relevant findings, it was possible to establish that interest and commitment increase in response to the teaching method supported with an augmented reality application for the measurement concept with respect to the traditional teaching method. The use of vision technologies in teaching the concept of measurement improves cognitive states of interest, commitment and reduces the level of stress.
Context.
Active M dwarfs frequently exhibit large flares, which can pose an existential threat to the habitability of any planet in orbit in addition to making said planets more difficult to detect. ...M dwarfs do not lose angular momentum as easily as earlier-type stars, which maintain the high levels of stellar activity for far longer. Studying young, fast-rotating M dwarfs is key to understanding their near stellar environment and the evolution of activity.
Aims.
We study stellar activity on the fast-rotating M dwarf GJ 3270.
Methods.
We analyzed dedicated high cadence, simultaneous, photometric and high-resolution spectroscopic observations obtained with CARMENES of GJ 3270 over 7.7 h, covering a total of eight flares of which two are strong enough to facilitate a detailed analysis. We consult the TESS data, obtained in the month prior to our own observations, to study rotational modulation and to compare the TESS flares to those observed in our campaign.
Results.
The TESS data exhibit rotational modulation with a period of 0.37 d. The strongest flare covered by our observing campaign released a total energy of about 3.6 × 10
32
erg, putting it close to the superflare regime. This flare is visible in the
B,V, r, i,
and
z
photometric bands, which allows us to determine a peak temperature of about 10 000 K. The flare also leaves clear marks in the spectral time series. In particular, we observe an evolving, mainly blue asymmetry in chromospheric lines, which we attribute to a post-flare, corotating feature. To our knowledge this is the first time such a feature has been seen on a star other than our Sun.
Conclusions.
Our photometric and spectroscopic time series covers the eruption of a strong flare followed up by a corotating feature analogous to a post-flare arcadal loop on the Sun with a possible failed ejection of material.
We report the discovery of two planetary systems, namely G 264–012, an M 4.0 dwarf with two terrestrial planets (
M
b
sin
i
=2.50
−0.30
+0.29
M
⊕
and
M
c
sin
i
=3.75
−0.47
+0.48
M
⊕
), and Gl 393, a ...bright M 2.0 dwarf with one terrestrial planet (
M
b
sin
i
= 1.71 ± 0.24
M
⊕
). Although both stars were proposed to belong to young stellar kinematic groups, we estimate their ages to be older than about 700 Ma. The two planets around G 264–012 were discovered using only radial-velocity (RV) data from the CARMENES exoplanet survey, with estimated orbital periods of 2.30 d and 8.05 d, respectively.Photometric monitoring and analysis of activity indicators reveal a third signal present in the RV measurements, at about 100 d,caused by stellar rotation. The planet Gl 393 b was discovered in the RV data from the HARPS, CARMENES, and HIRES instruments. Its identification was only possible after modelling, with a Gaussian process (GP), the variability produced by the magnetic activity of the star. For the earliest observations, this variability produced a forest of peaks in the periodogram of the RVs at around the 34 d rotation period determined from
Kepler
data, which disappeared in the latestepochs. After correcting for them with this GP model, a significant signal showed at a period of 7.03 d. No significant signals in any of our spectral activity indicators or contemporaneous photometry were found at any of the planetary periods. Given the orbital and stellar properties, the equilibrium temperatures of the three planets are all higher than that for Earth. Current planet formation theories suggest that these two systems represent a common type of architecture. This is consistent with formation following the core accretion paradigm.
Context.
M dwarfs are ideal targets for the search of Earth-size planets in the habitable zone using the radial velocity method, and are attracting the attention of many ongoing surveys. One of the ...expected results of these surveys is that new multiple-star systems have also been found. This is the case also for the CARMENES survey, thanks to which nine new double-line spectroscopic binary systems have already been announced.
Aims.
Throughout the five years of the survey the accumulation of new observations has resulted in the detection of several new multiple-stellar systems with long periods and low radial-velocity amplitudes. Here we newly characterise the spectroscopic orbits and constrain the masses of eight systems and update the properties of a system that we had reported earlier.
Methods.
We derived the radial velocities of the stars using two-dimensional cross-correlation techniques and template matching. The measurements were modelled to determine the orbital parameters of the systems. We combined CARMENES spectroscopic observations with archival high-resolution spectra from other instruments to increase the time span of the observations and improve our analysis. When available, we also added archival photometric, astrometric, and adaptive optics imaging data to constrain the rotation periods and absolute masses of the components.
Results.
We determined the spectroscopic orbits of nine multiple systems, eight of which are presented for the first time. The sample is composed of five single-line binaries, two double-line binaries, and two triple-line spectroscopic triple systems. The companions of two of the single-line binaries, GJ 3626 and GJ 912, have minimum masses below the stellar boundary, and thus could be brown dwarfs. We found a new white dwarf in a close binary orbit around the M star GJ 207.1, located at a distance of 15.79 pc. From a global fit to radial velocities and astrometric measurements, we were able to determine the absolute masses of the components of GJ 282 C, which is one of the youngest systems with measured dynamical masses.
CARMENES input catalog of M dwarfs Shan, Y.; Revilla, D.; Skrzypinski, S. L. ...
Astronomy and astrophysics (Berlin),
04/2024, Volume:
684
Journal Article
Peer reviewed
Open access
Aims. Knowledge of rotation periods ( P rot ) is important for understanding the magnetic activity and angular momentum evolution of late-type stars, as well as for evaluating radial velocity signals ...of potential exoplanets and identifying false positives. We measured photometric and spectroscopic P rot for a large sample of nearby bright M dwarfs with spectral types from M0 to M9, as part of our continual effort to fully characterize the Guaranteed Time Observation programme stars of the CARMENES survey. Methods. We analyse light curves chiefly from the SuperWASP survey and TESS data. We supplemented these with our own follow-up photometric monitoring programme from ground-based facilities, as well as spectroscopic indicator time series derived directly from the CARMENES spectra. Results. From our own analysis, we determined P rot for 129 stars. Combined with the literature, we tabulated P rot for 261 stars, or 75% of our sample. We developed a framework to evaluate the plausibility of all periods available for this sample by comparing them with activity signatures and checking for consistency between multiple measurements. We find that 166 of these stars have independent evidence that confirmed their P rot . There are inconsistencies in 27 periods, which we classify as debated. A further 68 periods are identified as provisional detections that could benefit from independent verification. We provide an empirical relation for the P rot uncertainty as a function of the P rot value, based on the dispersion of the measurements. We show that published formal errors seem to be often underestimated for periods longwards of ∼10 d. We examined rotation–activity relations with emission in X-rays, H α , Ca II H&K, and surface magnetic field strengths for this sample of M dwarfs. We find overall agreement with previous works, as well as tentative differences in the partially versus fully convective subsamples. We show P rot as a function of stellar mass, age, and galactic kinematics. With the notable exception of three transiting planet systems and TZ Ari, all known planet hosts in this sample have P rot ≳ 15 d. Conclusions. Inherent challenges in determining accurate and precise stellar P rot means independent verification is important, especially for inactive M dwarfs. Evidence of potential mass dependence in activity–rotation relations would suggest physical changes in the magnetic dynamo that warrants further investigation using larger samples of M dwarfs on both sides of the fully convective boundary. Important limitations need to be overcome before the radial velocity technique can be routinely used to detect and study planets around young and active stars.
Dynamical histories of planetary systems, as well as the atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS ...mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685 (2MASS J04342248+4302148). We confirm the planetary nature of the transit signal, which has a period of
P
b
= 0.6691403
−0.0000021
+0.0000023
d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of
M
b
= 3.78
−0.63
+0.63
M
⊕
, a radius of
R
b
= 1.70
−0.07
+0.07
R
⊕
, which together result in a bulk density of
ρ
b
= 4.21
−0.82
+0.95
g cm
−3
, and an equilibrium temperature of
T
eq
= 1069
−16
+16
K. TOI-1685 b is the least dense ultra-short-period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting super-Earth planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report with moderate evidence an additional non-transiting planet candidate in the system, TOI-1685 c, which has an orbital period of
P
c
= 9.02
−0.12
+0.10
d.
This article aims to describe the process of measuring mental state variables through a brain-computer interface in the interaction of humans with books with augmented reality; specifically, it seeks ...to analyze the variables commitment, stress, interest, relaxation, excitement, concentration in the interaction of students with a book with augmented reality compared with the measurement of the same variables when reading a traditional text. For the process of measuring emotional signals, two texts were designed for the data structure subject of the systems engineering program, the first in traditional format and the second with augmented reality applications. Subsequently, the mental state measures were taken through the brain-computer interface to the sample of students of the subject interacting with the traditional book and the book with augmented reality. Finally, through the interface software application, the results of the variables of each student interacting with the mentioned texts were downloaded and comparatively analyzed. Through comparative analysis, it is shown that the variable of mental state interest increases in the interaction of higher education students with books with augmented reality compared to reading a traditional text. Brain-computer interface systems have become an effective strategy for the measurement of emotional variables in the incorporation of emerging technologies such as augmented reality into teaching-learning processes in higher education.
Although M dwarfs are known for high levels of stellar activity, they are ideal targets for the search of low-mass exoplanets with the radial velocity (RV) method. We report the discovery of a ...planetary-mass companion around LSPM J2116+0234 (M3.0 V) and confirm the existence of a planet orbiting GJ 686 (BD+18 3421; M1.0 V). The discovery of the planet around LSPM J2116+0234 is based on CARMENES RV observations in the visual and near-infrared channels. We confirm the planet orbiting around GJ 686 by analyzing the RV data spanning over two decades of observationsfrom CARMENES VIS, HARPS-N, HARPS, and HIRES. We find planetary signals at 14.44 and 15.53 d in the RV data for LSPM J2116+0234 and GJ 686, respectively. Additionally, the RV, photometric time series, and various spectroscopic indicators show hints of variations of 42 d for LSPM J2116+0234 and 37 d for GJ 686, which we attribute to the stellar rotation periods. The orbital parameters of the planets are modeled with Keplerian fits together with correlated noise from the stellar activity. A mini-Neptune with a minimum mass of 11.8
M
⊕
orbits LSPM J2116+0234 producing a RV semi-amplitude of 6.19 m s
−1
, while a super-Earth of mass 6.6
M
⊕
orbits GJ 686 and produces a RV semi-amplitude of 3.0 m s
−1
. Both LSPM J2116+0234 and GJ 686 have planetary companions populating the regime of exoplanets with masses lower than 15
M
⊕
and orbital periods <20 d.
Planets with orbital periods shorter than 1 day are rare and have formation histories that are not completely understood. Small ( R p < 2 R ⊕ ) ultra-short-period (USP) planets are highly irradiated, ...probably have rocky compositions with high bulk densities, and are often found in multi-planet systems. Additionally, USP planets found around small stars are excellent candidates for characterization using present-day instrumentation. Of the current full sample of approximately 5500 confirmed exoplanets, only 130 are USP planets and around 40 have mass and radius measurements. Wolf 327 (TOI-5747) is an M dwarf ( R * = 0.406 ± 0.015 R ⊙ , M * = 0.405 ± 0.019 M ⊙ , T eff = 3542 ± 70 K, and V = 13 mag) located at a distance d = 28.5 pc. NASA’s planet hunter satellite, TESS, detected transits in this star with a period of 0.573 day (13.7 h) and with a transit depth of 818 ppm. Ground-based follow-up photometry, high resolution imaging, and radial velocity (RV) measurements taken with the CARMENES spectrograph confirm the presence of this new USP planet. Wolf 327b is a super-Earth with a radius of R p = 1.24 ± 0.06 R ⊕ and a mass of M p = 2.53 ± 0.46 M ⊕ , yielding a bulk density of 7.24 ± 1.66 g cm −3 and thus suggesting a rocky composition. Owing to its close proximity to its host star ( a = 0.01 au), Wolf 327b has an equilibrium temperature of 996 ± 22 K. This planet has a mass and radius similar to K2-229b, a planet with an inferred Mercury-like internal composition. Planet interior models suggest that Wolf 327b has a large iron core, a small rocky mantle, and a negligible (if any) H/He atmosphere.
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