scholarly journals CARMENES: Calar Alto high-resolution search for M dwarfs with exo-earths with a near-infrared Echelle spectrograph

2010 ◽  
Author(s):  
A. Quirrenbach ◽  
P. J. Amado ◽  
H. Mandel ◽  
J. A. Caballero ◽  
R. Mundt ◽  
...  
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
M Dwarfs ◽  
Echelle Spectrograph ◽  
Calar Alto

scholarly journals CARMENES: Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs

2010 ◽  
Vol 6 (S276) ◽  
pp. 545-546 ◽  
Author(s):  
Andreas Quirrenbach ◽  
Pedro J. Amado ◽  
José A. Caballero ◽  
Holger Mandel ◽  
Reinhard Mundt ◽  
...  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Emission Line ◽  
Wavelength Range ◽  
Spectral Resolution ◽  
Near Infrared ◽  
M Dwarfs ◽  
Simultaneous Emission ◽  
M Stars ◽  
Calar Alto

AbstractCARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a next-generation instrument for the 3.5 m telescope at the Calar Alto Observatory. CARMENES will conduct a five-year exoplanet survey targeting ~300 M stars. The CARMENES instrument consists of two separate fiber-fed spectrographs covering the wavelength range from 0.52 to 1.7 μm at a spectral resolution of R = 85,000. The spectrographs are housed in a temperature-stabilized environment in vacuum tanks, to enable a 1 m/s radial velocity precision employing a simultaneous emission-line calibration.

scholarly journals The CARMENES search for exoplanets around M dwarfs

2018 ◽  
Vol 615 ◽  
pp. A14 ◽  
Author(s):  
B. Fuhrmeister ◽  
S. Czesla ◽  
J. H. M. M. Schmitt ◽  
S. V. Jeffers ◽  
J. A. Caballero ◽  
...  
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Common Phenomenon ◽  
Complex Line ◽  
Line Profiles ◽  
Stark Broadening ◽  
M Dwarfs ◽  
Additional Line ◽  
Coronal Rain ◽  
Calar Alto

Stellar activity is ubiquitously encountered in M dwarfs and often characterised by the Hα line. In the most active M dwarfs, Hα is found in emission, sometimes with a complex line profile. Previous studies have reported extended wings and asymmetries in the Hα line during flares. We used a total of 473 high-resolution spectra of 28 active M dwarfs obtained by the CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-Earths with Near-infrared and optical Echelle Spectrographs) spectrograph to study the occurrence of broadened and asymmetric Hα line profiles and their association with flares, and examine possible physical explanations. We detected a total of 41 flares and 67 broad, potentially asymmetric, wings in Hα. The broadened Hα lines display a variety of profiles with symmetric cases and both red and blue asymmetries. Although some of these line profiles are found during flares, the majority are at least not obviously associated with flaring. We propose a mechanism similar to coronal rain or chromospheric downward condensations as a cause for the observed red asymmetries; the symmetric cases may also be caused by Stark broadening. We suggest that blue asymmetries are associated with rising material, and our results are consistent with a prevalence of blue asymmetries during the flare onset. Besides the Hα asymmetries, we find some cases of additional line asymmetries in He I D3, Na I D lines, and the He I line at 10 830 Å taken all simultaneously thanks to the large wavelength coverage of CARMENES. Our study shows that asymmetric Hα lines are a rather common phenomenon in M dwarfs and need to be studied in more detail to obtain a better understanding of the atmospheric dynamics in these objects.

scholarly journals Multi-Wavelength High-Resolution Spectroscopy for Exoplanet Detection: Motivation, Instrumentation and First Results

Geosciences ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 289 ◽  
Author(s):  
Serena Benatti
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Giant Planet ◽  
High Resolution Spectroscopy ◽  
M Dwarfs ◽  
Low Mass Stars ◽  
First Results ◽  
Multi Wavelength ◽  
Low Mass ◽  
Rocky Planets

Exoplanet research has shown an incessant growth since the first claim of a hot giant planet around a solar-like star in the mid-1990s. Today, the new facilities are working to spot the first habitable rocky planets around low-mass stars as a forerunner for the detection of the long-awaited Sun-Earth analog system. All the achievements in this field would not have been possible without the constant development of the technology and of new methods to detect more and more challenging planets. After the consolidation of a top-level instrumentation for high-resolution spectroscopy in the visible wavelength range, a huge effort is now dedicated to reaching the same precision and accuracy in the near-infrared. Actually, observations in this range present several advantages in the search for exoplanets around M dwarfs, known to be the most favorable targets to detect possible habitable planets. They are also characterized by intense stellar activity, which hampers planet detection, but its impact on the radial velocity modulation is mitigated in the infrared. Simultaneous observations in the visible and near-infrared ranges appear to be an even more powerful technique since they provide combined and complementary information, also useful for many other exoplanetary science cases.

scholarly journals The CARMENES search for exoplanets around M dwarfs

2020 ◽  
Vol 640 ◽  
pp. A50 ◽  
Author(s):  
F. F. Bauer ◽  
M. Zechmeister ◽  
A. Kaminski ◽  
C. Rodríguez López ◽  
J. A. Caballero ◽  
...  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Near Infrared ◽  
Work Flow ◽  
M Dwarfs ◽  
Dual Channel ◽  
Infrared Channel

The high-resolution, dual channel, visible and near-infrared spectrograph CARMENES offers exciting opportunities for stellar and exoplanetary research on M dwarfs. In this work we address the challenge of reaching the highest radial velocity precision possible with a complex, actively cooled, cryogenic instrument, such as the near-infrared channel. We describe the performance of the instrument and the work flow used to derive precise Doppler measurements from the spectra. The capability of both CARMENES channels to detect small exoplanets is demonstrated with the example of the nearby M5.0 V star CD Cet (GJ 1057), around which we announce a super-Earth (4.0 ± 0.4 M⊕) companion on a 2.29 d orbit.

scholarly journals CARMENES – M Dwarfs and their Planets: First Results

2016 ◽  
Vol 12 (S328) ◽  
pp. 46-53 ◽  
Author(s):  
A. Quirrenbach ◽  
P.J. Amado ◽  
I. Ribas ◽  
A. Reiners ◽  
J.A. Caballero ◽  
...  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Wavelength Range ◽  
Southern Spain ◽  
Science Program ◽  
Velocity Measurements ◽  
M Dwarfs ◽  
First Results ◽  
Calar Alto

AbstractCARMENES is a pair of high-resolution (R ≳ 80, 000) spectrographs covering the wavelength range from 0.52 to 1.71 μm with only small gaps. The instrument has been optimized for precise radial velocity measurements. It was installed and commissioned at the 3.5 m telescope of the Calar Alto observatory in Southern Spain in 2015. The first large science program of CARMENES is a survey of ~300 M dwarfs, which started on Jan 1, 2016. We present an overview of the instrument, and provide a few examples of early science results.

scholarly journals The CARMENES search for exoplanets around M dwarfs

2020 ◽  
Vol 642 ◽  
pp. A22 ◽  
Author(s):  
V. M. Passegger ◽  
A. Bello-García ◽  
J. Ordieres-Meré ◽  
J. A. Caballero ◽  
A. Schweitzer ◽  
...  
Keyword(s):  
Neural Network ◽  
High Resolution ◽  
Network Architecture ◽  
Near Infrared ◽  
Rotational Velocity ◽  
M Dwarfs ◽  
Convolutional Network ◽  
Fast Analysis ◽  
Infrared Wavelength ◽  
The Impact

Existing and upcoming instrumentation is collecting large amounts of astrophysical data, which require efficient and fast analysis techniques. We present a deep neural network architecture to analyze high-resolution stellar spectra and predict stellar parameters such as effective temperature, surface gravity, metallicity, and rotational velocity. With this study, we firstly demonstrate the capability of deep neural networks to precisely recover stellar parameters from a synthetic training set. Secondly, we analyze the application of this method to observed spectra and the impact of the synthetic gap (i.e., the difference between observed and synthetic spectra) on the estimation of stellar parameters, their errors, and their precision. Our convolutional network is trained on synthetic PHOENIX-ACES spectra in different optical and near-infrared wavelength regions. For each of the four stellar parameters, Teff, log g, [M/H], and v sin i, we constructed a neural network model to estimate each parameter independently. We then applied this method to 50 M dwarfs with high-resolution spectra taken with CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Échelle Spectrographs), which operates in the visible (520–960 nm) and near-infrared wavelength range (960–1710 nm) simultaneously. Our results are compared with literature values for these stars. They show mostly good agreement within the errors, but also exhibit large deviations in some cases, especially for [M/H], pointing out the importance of a better understanding of the synthetic gap.

scholarly journals Diving Beneath the Sea of Stellar Activity: Chromatic Radial Velocities of the Young AU Mic Planetary System

2021 ◽  
Vol 162 (6) ◽  
pp. 295
Author(s):  
Bryson L. Cale ◽  
Michael Reefe ◽  
Peter Plavchan ◽  
Angelle Tanner ◽  
Eric Gaidos ◽  
...  
Keyword(s):  
Process Model ◽  
Near Infrared ◽  
Wavelength Dependence ◽  
M Dwarfs ◽  
Echelle Spectrograph ◽  
Stellar Activity ◽  
Transiting Planets ◽  
Order Of Magnitude ◽  
Modeling Toolkit ◽  
M Dwarf

Abstract We present updated radial-velocity (RV) analyses of the AU Mic system. AU Mic is a young (22 Myr) early-M dwarf known to host two transiting planets—P b ∼ 8.46 days, R b = 4.38 − 0.18 + 0.18 R ⊕ , P c ∼ 18.86 days, R c = 3.51 − 0.16 + 0.16 R ⊕ . With visible RVs from Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical echelle Spectrographs (CARMENES)-VIS, CHIRON, HARPS, HIRES, Minerva-Australis, and Tillinghast Reflector Echelle Spectrograph, as well as near-infrared (NIR) RVs from CARMENES-NIR, CSHELL, IRD, iSHELL, NIRSPEC, and SPIRou, we provide a 5σ upper limit to the mass of AU Mic c of M c ≤ 20.13 M ⊕ and present a refined mass of AU Mic b of M b = 20.12 − 1.57 + 1.72 M ⊕ . Used in our analyses is a new RV modeling toolkit to exploit the wavelength dependence of stellar activity present in our RVs via wavelength-dependent Gaussian processes. By obtaining near-simultaneous visible and near-infrared RVs, we also compute the temporal evolution of RV “color” and introduce a regressional method to aid in isolating Keplerian from stellar activity signals when modeling RVs in future works. Using a multiwavelength Gaussian process model, we demonstrate the ability to recover injected planets at 5σ significance with semi-amplitudes down to ≈10 m s−1 with a known ephemeris, more than an order of magnitude below the stellar activity amplitude. However, we find that the accuracy of the recovered semi-amplitudes is ∼50% for such signals with our model.

scholarly journals Detection of He I λ10830 Å absorption on HD 189733 b with CARMENES high-resolution transmission spectroscopy

2018 ◽  
Vol 620 ◽  
pp. A97 ◽  
Author(s):  
M. Salz ◽  
S. Czesla ◽  
P. C. Schneider ◽  
E. Nagel ◽  
J. H. M. M. Schmitt ◽  
...  
Keyword(s):  
High Resolution ◽  
Rest Frame ◽  
Near Infrared ◽  
Radial Velocities ◽  
Helium Atmosphere ◽  
Absorption Signal ◽  
The Mean ◽  
Third Line ◽  
Calar Alto ◽  
Absorption Level

We present three transit observations of HD 189733 b obtained with the high-resolution spectrograph CARMENES at Calar Alto. A strong absorption signal is detected in the near-infrared He I triplet at 10830 Å in all three transits. During mid-transit, the mean absorption level is 0.88 ± 0.04% measured in a ±10 km s−1 range at a net blueshift of − 3.5 ± 0.4 km s−1 (10829.84–10830.57 Å). The absorption signal exhibits radial velocities of + 6.5 ± 3.1 km s−1 and − 12.6 ± 1.0 km s−1 during ingress and egress, respectively; all radial velocities are measured in the planetary rest frame. We show that stellar activity related pseudo-signals interfere with the planetary atmospheric absorption signal. They could contribute as much as 80% of the observed signal and might also affect the observed radial velocity signature, but pseudo-signals are very unlikely to explain the entire signal. The observed line ratio between the two unresolved and the third line of the He I triplet is 2.8 ± 0.2, which strongly deviates from the value expected for an optically thin atmospheres. When interpreted in terms of absorption in the planetary atmosphere, this favors a compact helium atmosphere with an extent of only 0.2 planetary radii and a substantial column density on the order of 4 × 1012 cm−2. The observed radial velocities can be understood either in terms of atmospheric circulation with equatorial superrotation or as a sign of an asymmetric atmospheric component of evaporating material. We detect no clear signature of ongoing evaporation, like pre- or post-transit absorption, which could indicate material beyond the planetary Roche lobe, or radial velocities in excess of the escape velocity. These findings do not contradict planetary evaporation, but only show that the detected helium absorption in HD 189733 b does not trace the atmospheric layers that show pronounced escape signatures.

scholarly journals Kinematics of M dwarfs in the CARMENES Input Catalogue: Membership in Young Moving Groups

2015 ◽  
Vol 10 (S314) ◽  
pp. 71-72
Author(s):  
D. Montes ◽  
J. A. Caballero ◽  
I. Gallardo ◽  
M. Cortés-Contreras ◽  
F. J. Alonso-Floriano
Keyword(s):  
Near Infrared ◽  
Distance Estimation ◽  
Age Dating ◽  
Velocity Measurements ◽  
M Dwarfs ◽  
Dating Methods ◽  
Moving Groups ◽  
Input Catalogue ◽  
Photometric Distance ◽  
Calar Alto

AbstractWe present a detailed study of the kinematics of M dwarfs in the CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) input catalog. We have selected all M dwarfs with known parallactic distance or a good photometric distance estimation, precise proper motion in the literature or as determined by us, and radial velocity measurements. Using these parameters, we computed the M dwarfs galactic space motions (U, V, W). For the stars with U and V velocity components inside or near the boundaries that determine the young disk population, we have analyzed the possible membership in the classical moving groups and nearby loose associations with ages between 10 and 600 Myr. For the candidate members, we have compiled information available in the literature in order to constrain their membership by applying other age-dating methods.

scholarly journals Exploring the stellar properties of M dwarfs with high-resolution spectroscopy from the optical to the near-infrared (Corrigendum)

2019 ◽  
Vol 622 ◽  
pp. C1 ◽  
Author(s):  
A. S. Rajpurohit ◽  
F. Allard ◽  
S. Rajpurohit ◽  
R. Sharma ◽  
G. D. C. Teixeira ◽  
...  
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
High Resolution Spectroscopy ◽  
M Dwarfs ◽  
Stellar Properties
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