NEAR-INFRARED METALLICITIES, RADIAL VELOCITIES, AND SPECTRAL TYPES FOR 447 NEARBY M DWARFS

AbstractThe TEDI (TripleSpec - Exoplanet Discovery Instrument) is a dedicated instrument for the near-infrared radial velocity search for planetary companions to low-mass stars with the goal of achieving meters-per-second radial velocity precision. Heretofore, such planet searches have been limited almost entirely to the optical band and to stars that are bright in this band. Consequently, knowledge about planetary companions to the populous but visibly faint low-mass stars is limited. In addition to the opportunity afforded by precision radial velocity searches directly for planets around low mass stars, transits around the smallest M dwarfs offer a chance to detect the smallest possible planets in the habitable zones of the parent stars. As has been the the case with followup of planet candidates detected by the transit method requiring radial velocity confirmation, the capability to undertake efficient precision radial velocity measurements of mid-late M dwarfs will be required. TEDI has been commissioned on the Palomar 200” telescope in December 2007, and is currently in a science verification phase.

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The CARMENES search for exoplanets around M dwarfs

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935460 ◽

2019 ◽

Vol 627 ◽

pp. A49 ◽

Cited By ~ 30

Author(s):

M. Zechmeister ◽

S. Dreizler ◽

I. Ribas ◽

A. Reiners ◽

J. A. Caballero ◽

...

Keyword(s):

Radial Velocity ◽

Near Infrared ◽

Radial Velocities ◽

Slow Rotation ◽

M Dwarfs ◽

Photometric Variability ◽

Photometric Measurements ◽

The Masses ◽

Rule Out

Context. Teegarden’s Star is the brightest and one of the nearest ultra-cool dwarfs in the solar neighbourhood. For its late spectral type (M7.0 V), the star shows relatively little activity and is a prime target for near-infrared radial velocity surveys such as CARMENES. Aims. As part of the CARMENES search for exoplanets around M dwarfs, we obtained more than 200 radial-velocity measurements of Teegarden’s Star and analysed them for planetary signals. Methods. We find periodic variability in the radial velocities of Teegarden’s Star. We also studied photometric measurements to rule out stellar brightness variations mimicking planetary signals. Results. We find evidence for two planet candidates, each with 1.1 M⊕ minimum mass, orbiting at periods of 4.91 and 11.4 d, respectively. No evidence for planetary transits could be found in archival and follow-up photometry. Small photometric variability is suggestive of slow rotation and old age. Conclusions. The two planets are among the lowest-mass planets discovered so far, and they are the first Earth-mass planets around an ultra-cool dwarf for which the masses have been determined using radial velocities.

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Structure and dynamics of the Milky Way disk as revealed from the radial velocity distributions of APOGEE red clump stars

Proceedings of the International Astronomical Union ◽

10.1017/s174392131601173x ◽

2016 ◽

Vol 11 (S321) ◽

pp. 50-50

Author(s):

Daisuke Toyouchi ◽

Masashi Chiba

Keyword(s):

Near Infrared ◽

Milky Way ◽

Radial Velocities ◽

Galactocentric Distance ◽

Chemical Abundances ◽

Structure And Dynamics ◽

Evolution Experiment ◽

Dynamical Properties ◽

Red Clump ◽

Independent Work

AbstractWe investigate the structure and dynamics of the Milky Way (MW) disk stars based on the analysis of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) data, to infer the past evolution histories of the MW disk component(s) possibly affected by radial migration and/or satellite accretions. APOGEE is the first near-infrared spectroscopic survey for a large number of the MW disk stars, providing their radial velocities and chemical abundances without significant dust extinction effects. We here adopt red-clump (RC) stars (Bovy et al. 2014), for which the distances from the Sun are determined precisely, and analyze their radial velocities and chemical abundances in the MW disk regions covering from the Galactocentric distance, R, of 5 kpc to 14 kpc. We investigate their dynamical properties, such as mean rotational velocities, 〈Vφ〉 and velocity dispersions, as a function of R, based on the MCMC Bayesian method. We find that at all radii, the dynamics of alpha-poor stars, which are candidates of young disk stars, is much different from that of alpha-rich stars, which are candidates of old disk stars. We find that our Jeans analysis for our sample stars reveals characteristic spatial and dynamical properties of the MW disk, which are generally in agreement with the recent independent work by Bovy et al. (2015) but with a different method from ours.

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Radial velocities of K–M dwarfs and local stellar kinematics

Astronomy and Astrophysics ◽

10.1051/0004-6361/201527850 ◽

2016 ◽

Vol 596 ◽

pp. A116 ◽

Cited By ~ 17

Author(s):

J. Sperauskas ◽

S. Bartašiūtė ◽

R. P. Boyle ◽

V. Deveikis ◽

S. Raudeliūnas ◽

...

Keyword(s):

Radial Velocities ◽

Stellar Kinematics ◽

M Dwarfs

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High precision radial velocities in the near-infrared domain: Status and prospects

EPJ Web of Conferences ◽

10.1051/epjconf/20111602001 ◽

2011 ◽

Vol 16 ◽

pp. 02001

Author(s):

E.L. Martín ◽

E. Guenther ◽

C. del Burgo ◽

M.R. Zapatero Osorio ◽

R. Deshpande ◽

...

Keyword(s):

High Precision ◽

Near Infrared ◽

Radial Velocities

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

Geosciences ◽

10.3390/geosciences8080289 ◽

2018 ◽

Vol 8 (8) ◽

pp. 289 ◽

Cited By ~ 1

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.

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The CARMENES search for exoplanets around M dwarfs

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038279 ◽

2020 ◽

Vol 640 ◽

pp. A52

Author(s):

B. Fuhrmeister ◽

S. Czesla ◽

L. Hildebrandt ◽

E. Nagel ◽

J. H. M. M. Schmitt ◽

...

Keyword(s):

Near Infrared ◽

Extreme Ultraviolet ◽

High Energy ◽

M Dwarfs ◽

Dwarf Stars ◽

Transmission Spectroscopy ◽

Solar Type ◽

Energy Irradiation ◽

Planetary Transmission ◽

M Dwarf Stars

The He I infrared (IR) triplet at 10 830 Å is known as an activity indicator in solar-type stars and has become a primary diagnostic in exoplanetary transmission spectroscopy. He I IR lines are a tracer of the stellar extreme-ultraviolet irradiation from the transition region and corona. We study the variability of the He I triplet lines in a spectral time series of 319 M dwarf stars that was obtained with the CARMENES high-resolution optical and near-infrared spectrograph at Calar Alto. We detect He I IR line variability in 18% of our sample stars, all of which show Hα in emission. Therefore, we find detectable He I variability in 78% of the sub-sample of stars with Hα emission. Detectable variability is strongly concentrated in the latest spectral sub-types, where the He I lines during quiescence are typically weak. The fraction of stars with detectable He I variation remains lower than 10% for stars earlier than M3.0 V, while it exceeds 30% for the later spectral sub-types. Flares are accompanied by particularly pronounced line variations, including strongly broadened lines with red and blue asymmetries. However, we also find evidence for enhanced He I absorption, which is potentially associated with increased high-energy irradiation levels at flare onset. Generally, He I and Hα line variations tend to be correlated, with Hα being the most sensitive indicator in terms of pseudo-equivalent width variation. This makes the He I triplet a favourable target for planetary transmission spectroscopy.

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Results of the SiO Maser Survey of the Galactic Bulge IRAS Sources

Symposium - International Astronomical Union ◽

10.1017/s0074180900229598 ◽

1996 ◽

Vol 169 ◽

pp. 119-124

Author(s):

S. Deguchi ◽

N. Ukita ◽

H. Izumiura ◽

T. Ono ◽

Y. Nakada ◽

...

Keyword(s):

Point Source ◽

Near Infrared ◽

Radial Velocities ◽

Galactic Bulge ◽

Entire Region ◽

Dust Extinction ◽

Optical Wavelengths

Evidence for the bar structure in our Galaxy has been shown by Blitz and Spergel (1991b) based on the near-infrared maps of the bulge, by Nakada et al. (1991) based on IRAS point source catalogue, and more clearly by recent COBE maps. However, no clear “dynamical” signature of the bulge bar has been found yet. At optical wavelengths, stellar radial velocities of the bulge stars were observed only at the optical windows and were not observed for the entire region of the bulge because of the dust extinction in this direction.

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The Near Infrared FeH Lines as Indicators of Surface Gravity of M stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900233597 ◽

1996 ◽

Vol 171 ◽

pp. 441-441

Author(s):

Ricardo Piorno Schiavon ◽

Beatriz Barbuy

Keyword(s):

Near Infrared ◽

Synthesis Method ◽

Population Synthesis ◽

Atmospheric Parameters ◽

M Dwarfs ◽

Synthetic Spectra ◽

Iron Hydride ◽

M Stars ◽

M Dwarf ◽

Ongoing Project

We compute synthetic spectra in the region around 1 μm, including the Wing-Ford band (WFB) of Iron Hydride (FeH) in the calculations. This band is known to be a good indicator of surface gravities of M stars. Employing Kurucz model atmospheres, we study the response of the intensity of the WFB to atmospheric parameters and check our results against observations of M dwarfs. This study is part of an ongoing project which aims to investigate the M dwarf-to-giant ratio in galaxies, through a population synthesis method, exploring a number of spectral indicators in the near infrared, such as the WFB, the NaI, CaII and CO near infrared features.

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The CARMENES search for exoplanets around M dwarfs

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038031 ◽

2020 ◽

Vol 640 ◽

pp. A50 ◽

Cited By ~ 2

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.

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