We present the PMAS/PPak Integral-field Supernova hosts COmpilation (PISCO), which comprises integral field spectroscopy (IFS) of 232 supernova (SN) host galaxies that hosted 272 SNe, observed over ...several semesters with the 3.5 m telescope at the Calar Alto Observatory (CAHA). PISCO is the largest collection of SN host galaxies observed with wide-field IFS, totaling 466,347 individual spectra covering a typical spatial resolution of ∼380 pc. Focused studies regarding specific SN Ia-related topics will be published elsewhere; this paper aims to present the properties of the SN environments, using stellar population (SP) synthesis, and the gas-phase interstellar medium, providing additional results separating stripped-envelope SNe into their subtypes. With 11,270 H ii regions detected in all galaxies, we present for the first time a statistical analysis of H ii regions, which puts H ii regions that have hosted SNe in context with all other star-forming clumps within their galaxies. SNe Ic are associated with environments that are more metal-rich and have higher EW(H ) and higher star formation rate within their host galaxies than the mean of all H ii regions detected within each host. This in contrast to SNe IIb, which occur in environments that are very different compared to other core-collapse SNe types. We find two clear components of young and old SPs at SNe IIn locations. We find that SNe II fast decliners tend to explode at locations where the SFR is more intense. Finally, we outline how a future dedicated IFS survey of galaxies in parallel to an untargeted SN search would overcome the biases in current environmental studies.
Ultra-hot Jupiters (UHJs) are highly irradiated giant exoplanets with extremely high day-side temperatures, which lead to thermal dissociation of most molecular species. It is expected that the ...neutral hydrogen atom is one of the main species in the upper atmospheres of UHJs. Neutral hydrogen has been detected in several UHJs by observing their Balmer line absorption. In this work, we report four transit observations of the UHJ WASP-33b, performed with the CARMENES and HARPS-North spectrographs, and the detection of the H
α
, H
β
, and H
γ
lines in the planetary transmission spectrum. The combined H
α
transmission spectrum of the four transits has an absorption depth of 0.99 ± 0.05%, which corresponds to an effective radius of 1.31 ± 0.01
R
p
. The strong H
α
absorption indicates that the line probes the high-altitude thermosphere. We further fitted the three Balmer lines using the
PAWN
model, assuming that the atmosphere is hydrodynamic and in local thermodynamic equilibrium. We retrieved a thermosphere temperature 12 200
−1000
+1300
K and a mass-loss rate
Ṁ
= 1011.8
−0.5
+0.6
g s
−1
. The retrieved high mass-loss rate is compatible with the “Balmer-driven” atmospheric escape scenario, in which the stellar Balmer continua radiation in the near-ultraviolet is substantially absorbed by excited hydrogen atoms in the planetary thermosphere.
Context. M dwarfs are known to generate the strongest magnetic fields among main-sequence stars with convective envelopes, but we are still lacking a consistent picture of the link between the ...magnetic fields and underlying dynamo mechanisms, rotation, and activity. Aims. In this work we aim to measure magnetic fields from the high-resolution near-infrared spectra taken with the CARMENES radial-velocity planet survey in a sample of 29 active M dwarfs and compare our results against stellar parameters. Methods. We used the state-of-the-art radiative transfer code to measure total magnetic flux densities from the Zeeman broadening of spectral lines and filling factors. Results. We detect strong kG magnetic fields in all our targets. In 16 stars the magnetic fields were measured for the first time. Our measurements are consistent with the magnetic field saturation in stars with rotation periods P < 4 d. The analysis of the magnetic filling factors reveal two different patterns of either very smooth distribution or a more patchy one, which can be connected to the dynamo state of the stars and/or stellar mass. Conclusions. Our measurements extend the list of M dwarfs with strong surface magnetic fields. They also allow us to better constrain the interplay between the magnetic energy, stellar rotation, and underlying dynamo action. The high spectral resolution and observations at near-infrared wavelengths are the beneficial capabilities of the CARMENES instrument that allow us to address important questions about the stellar magnetism.
ABSTRACT
CAFE is a high-resolution spectrograph with high-precision radial velocity capabilities mounted at the 2.2 m telescope of Calar Alto Observatory. It suffered from strong degradation after ...4 yr of operations and it has now been upgraded. The upgrades of the instrument (now named CAFE2) aimed at recovering the throughput and improving the stability due to the installation of a new grating, an active temperature control in the isolated coudé room, and a new scrambling system. In this paper, we present the results of the new commissioning of the instrument and a new pipeline (CAFExtractor) that provides the user with fully reduced data including radial velocity measurements of FGK dwarf stars. The commissioning results show a clear improvement in the instrument performance. The room temperature is now stabilized down to 5 mK during one night and below 50 mK over two months. CAFE2 now provides 3 m s−1 precision on the reference ThAr frames and the on-sky tests provide a radial velocity precision of 8 m s−1 during one night (for S/N > 50). The throughput of the instrument is now back to nominal values with an efficiency of around 15 per cent at 550 nm. The limiting magnitude of the instrument for a 1 h exposure and S/N = 20 is V = 15. With all these properties, CAFE enters into the small family of high-resolution spectrographs at 2–4 m telescopes capable of reaching radial velocity precisions below 10 m s−1.
Deriving metallicities for solar-like stars follows well-established methods, but for cooler stars such as M dwarfs, the determination is much more complicated due to forests of molecular lines that ...are present. Several methods have been developed in recent years to determine accurate stellar parameters for these cool stars (
T
eff
≲ 4000 K). However, significant differences can be found at times when comparing metallicities for the same star derived using different methods. In this work, we determine the effective temperatures, surface gravities, and metallicities of 18 well-studied M dwarfs observed with the CARMENES high-resolution spectrograph following different approaches, including synthetic spectral fitting, analysis of pseudo-equivalent widths, and machine learning. We analyzed the discrepancies in the derived stellar parameters, including metallicity, in several analysis runs. Our goal is to minimize these discrepancies and find stellar parameters that are more consistent with the literature values. We attempted to achieve this consistency by standardizing the most commonly used components, such as wavelength ranges, synthetic model spectra, continuum normalization methods, and stellar parameters. We conclude that although such modifications work quite well for hotter main-sequence stars, they do not improve the consistency in stellar parameters for M dwarfs, leading to mean deviations of around 50–200 K in temperature and 0.1–0.3 dex in metallicity. In particular, M dwarfs are much more complex and a standardization of the aforementioned components cannot be considered as a straightforward recipe for bringing consistency to the derived parameters. Further in-depth investigations of the employed methods would be necessary in order to identify and correct for the discrepancies that remain.
We present here CAFE, the Calar Alto Fiber-fed Échelle spectrograph, a new instrument built at the Centro Astronomico Hispano Alemán (CAHA). CAFE is a single-fiber, high-resolution (R ~ 70 000) ...spectrograph, covering the wavelength range between 3650−9800 Å. It was built on the basis of the common design for Échelle spectrographs. Its main aim is to measure radial velocities of stellar objects up to V ~ 13−14 mag with a precision as good as a few tens of m s-1. To achieve this goal the design was simplified at maximum, removing all possible movable components, the central wavelength is fixed, as is the wavelength coverage; there is no filter wheel, etc. Particular care was taken with the thermal and mechanical stability. The instrument is fully operational and publically accessible at the 2.2 m telescope of the Calar Alto Observatory. In this article we describe (i) the design, summarizing its manufacturing phase; (ii) characterize the main properties of the instrument; (iii) describe the reduction pipeline; and (iv) show the results from the first light and commissioning runs. The preliminar results indicate that the instrument fulfills the specifications and can achieve the planned goals. In particular, the results show that the instrument is more efficient than anticipated, reaching a signal-to-noise of ~20 for a stellar object as faint as V ~ 14.5 mag in ~2700 s integration time. The instrument is a wonderful machine for exoplanetary research (by studying large samples of possible systems cotaining massive planets), galactic dynamics (highly precise radial velocities in moving groups or stellar associations), or astrochemistry.
One of the main objectives of the Transiting Exoplanet Survey Satellite (TESS) mission is the discovery of small rocky planets around relatively bright nearby stars. Here, we report the discovery and ...characterization of the transiting super-Earth planet orbiting LHS 1478 (TOI-1640). The star is an inactive red dwarf (
J
~ 9.6 mag and spectral type m3 V) with mass and radius estimates of 0.20 ± 0.01
M
⊙
and 0.25 ± 0.01
R
⊙
, respectively, and an effective temperature of 3381 ± 54 K. It was observed by TESS in four sectors. These data revealed a transit-like feature with a period of 1.949 days. We combined the TESS data with three ground-based transit measurements, 57 radial velocity (RV) measurements from CARMENES, and 13 RV measurements from IRD, determining that the signal is produced by a planet with a mass of 2.33
−0.20
+0.20
M
⊕
and a radius of 1.24
−0.05
+0.05
R
⊕
. The resulting bulk density of this planet is 6.67 g cm
−3
, which is consistent with a rocky planet with an Fe- and MgSiO
3
-dominated composition. Although the planet would be too hot to sustain liquid water on its surface (its equilibrium temperature is about ~595 K, suggesting aVenus-like atmosphere), spectroscopic metrics based on the capabilities of the forthcoming
James Webb
Space Telescope and the fact that the host star is rather inactive indicate that this is one of the most favorable known rocky exoplanets for atmospheric characterization.
We present the discovery of an Earth-mass planet (
M
b
sin
i
= 1.26 ± 0.21
M
⊕
) on a 15.6 d orbit of a relatively nearby (
d ~
9.6 pc) and low-mass (0.167 ± 0.011
M
⊙
) M5.0 V star, Wolf 1069. ...Sitting at a separation of 0.0672 ± 0.0014 au away from the host star puts Wolf 1069 b in the habitable zone (HZ), receiving an incident flux of
S
= 0.652 ± 0.029
S
⊕
. The planetary signal was detected using telluric-corrected radial-velocity (RV) data from the CARMENES spectrograph, amounting to a total of 262 spectroscopic observations covering almost four years. There are additional long-period signals in the RVs, one of which we attribute to the stellar rotation period. This is possible thanks to our photometric analysis including new, well-sampled monitoring campaigns undergone with the OSN and TJO facilities that supplement archival photometry (i.e., from MEarth and SuperWASP), and this yielded an updated rotational period range of
P
rot
= 150–170 d, with a likely value at 169.3
−3.6
+3.7
. The stellar activity indicators provided by the CARMENES spectra likewise demonstrate evidence for the slow rotation period, though not as accurately due to possible factors such as signal aliasing or spot evolution. Our detectability limits indicate that additional planets more massive than one Earth mass with orbital periods of less than 10 days can be ruled out, suggesting that perhaps Wolf 1069 b had a violent formation history. This planet is also the sixth closest Earth-mass planet situated in the conservative HZ, after Proxima Centauri b, GJ 1061 d, Teegarden’s Star c, and GJ 1002 b and c. Despite not transiting, Wolf 1069 b is nonetheless a very promising target for future three-dimensional climate models to investigate various habitability cases as well as for sub-m s
−1
RV campaigns to search for potential inner sub-Earth-mass planets in order to test planet formation theories.
We report the discovery and characterisation of two Earth-mass planets orbiting in the habitable zone of the nearby M-dwarf GJ 1002 based on the analysis of the radial-velocity (RV) time series from ...the ESPRESSO and CARMENES spectrographs. The host star is the quiet M5.5 V star GJ 1002 (relatively faint in the optical,
V ~
13.8 mag, but brighter in the infrared,
J ~
8.3 mag), located at 4.84 pc from the Sun. We analyse 139 spectroscopic observations taken between 2017 and 2021. We performed a joint analysis of the time series of the RV and full-width half maximum (FWHM) of the cross-correlation function (CCF) to model the planetary and stellar signals present in the data, applying Gaussian process regression to deal with the stellar activity. We detect the signal of two planets orbiting GJ 1002. GJ 1002 b is a planet with a minimum mass
m
p
sin
i
of 1.08 ± 0.13
M
⊕
with an orbital period of 10.3465 ± 0.0027 days at a distance of 0.0457 ± 0.0013 au from its parent star, receiving an estimated stellar flux of 0.67
F
⊕
. GJ 1002 c is a planet with a minimum mass
m
p
sin
i
of 1.36 ± 0.17
M
⊕
with an orbital period of 20.202 ± 0.013 days at a distance of 0.0738 ± 0.0021 au from its parent star, receiving an estimated stellar flux of 0.257
F
⊕
. We also detect the rotation signature of the star, with a period of 126 ± 15 days. We find that there is a correlation between the temperature of certain optical elements in the spectrographs and changes in the instrumental profile that can affect the scientific data, showing a seasonal behaviour that creates spurious signals at periods longer than ~200 days. GJ 1002 is one of the few known nearby systems with planets that could potentially host habitable environments. The closeness of the host star to the Sun makes the angular sizes of the orbits of both planets (~9.7 mas and ~15.7 mas, respectively) large enough for their atmosphere to be studied via high-contrast high-resolution spectroscopy with instruments such as the future spectrograph ANDES for the ELT or the LIFE mission.
Context.
Ground-based observing time is precious in the era of exoplanet follow-up and characterization, especially in high-precision radial velocity instruments. Blind-search radial velocity surveys ...thus require a dedicated observational strategy in order to optimize the observing time, which is particularly crucial for the detection of small rocky worlds at large orbital periods.
Aims.
We developed an algorithm with the purpose of improving the efficiency of radial velocity observations in the context of exoplanet searches, and we applied it to the K-dwarfs Orbited By habitable Exoplanets experiment. Our aim is to accelerate exoplanet confirmations or, alternatively, reject false signals as early as possible in order to save telescope time and increase the efficiency of both blind-search surveys and follow-up of transiting candidates.
Methods.
Once a minimum initial number of radial velocity datapoints is reached in such a way that a periodicity starts to emerge according to generalized Lomb-Scargle periodograms, that period is targeted with the proposed algorithm, named KOBEsim. The algorithm selects the next observing date that maximizes the Bayesian evidence for this periodicity in comparison with a model with no Keplerian orbits.
Results.
By means of simulated data, we proved that the algorithm accelerates the exoplanet detection, needing 29-33% fewer observations and a 41–47% smaller time span of the full dataset for low-mass planets (
m
p
< 10
M
⊕
) in comparison with a conventional monotonic cadence strategy. For 20
M
⊕
planets we found a 16% enhancement in the number of datapoints. We also tested KOBEsim with real data for a particular KOBE target and for the confirmed planet HD 102365 b. These two tests demonstrate that the strategy is capable of speeding up the detection by up to a factor of 2 (i.e., reducing both the time span and number of observations by half).
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