scholarly journals DETECTING PLANETS AROUND VERY LOW MASS STARS WITH THE RADIAL VELOCITY METHOD

2010 ◽  
Vol 710 (1) ◽  
pp. 432-443 ◽  
Author(s):  
A. Reiners ◽  
J. L. Bean ◽  
K. F. Huber ◽  
S. Dreizler ◽  
A. Seifahrt ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Low Mass Stars ◽  
Low Mass

scholarly journals Spectrum radial velocity analyser (SERVAL)

2017 ◽  
Vol 609 ◽  
pp. A12 ◽  
Author(s):  
M. Zechmeister ◽  
A. Reiners ◽  
P. J. Amado ◽  
M. Azzaro ◽  
F. F. Bauer ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Line Width ◽  
Active Regions ◽  
High Signal ◽  
Chromatic Index ◽  
Visual Channel ◽  
Low Mass Stars ◽  
Differential Line ◽  
Spectral Diagnostics ◽  
Low Mass

Context. The CARMENES survey is a high-precision radial velocity (RV) programme that aims to detect Earth-like planets orbiting low-mass stars. Aims. We develop least-squares fitting algorithms to derive the RVs and additional spectral diagnostics implemented in the SpEctrum Radial Velocity AnaLyser (SERVAL), a publicly available python code. Methods. We measured the RVs using high signal-to-noise templates created by coadding all available spectra of each star. We define the chromatic index as the RV gradient as a function of wavelength with the RVs measured in the echelle orders. Additionally, we computed the differential line width by correlating the fit residuals with the second derivative of the template to track variations in the stellar line width. Results. Using HARPS data, our SERVAL code achieves a RV precision at the level of 1 m/s. Applying the chromatic index to CARMENES data of the active star YZ CMi, we identify apparent RV variations induced by stellar activity. The differential line width is found to be an alternative indicator to the commonly used full width half maximum. Conclusions. We find that at the red optical wavelengths (700–900 nm) obtained by the visual channel of CARMENES, the chromatic index is an excellent tool to investigate stellar active regions and to identify and perhaps even correct for activity-induced RV variations.

scholarly journals Lyα Observations of High Radial Velocity Low-mass Stars Ross 1044 and Ross 825

2019 ◽  
Vol 886 (1) ◽  
pp. 19 ◽  
Author(s):  
Adam C. Schneider ◽  
Evgenya L. Shkolnik ◽  
Travis S. Barman ◽  
R. Parke Loyd
Keyword(s):  
Radial Velocity ◽  
Low Mass Stars ◽  
Low Mass

scholarly journals Precision Radial Velocities in the Near Infrared with TEDI

2008 ◽  
Vol 4 (S253) ◽  
pp. 157-161 ◽  
Author(s):  
James P. Lloyd ◽  
Agnieszka Czeszumska ◽  
Jerry Edelstein ◽  
David Erskine ◽  
Michael Feuerstein ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Near Infrared ◽  
Radial Velocities ◽  
Velocity Measurements ◽  
M Dwarfs ◽  
Low Mass Stars ◽  
Habitable Zones ◽  
Low Mass ◽  
Transit Method

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.

scholarly journals The Milky Way evolution under the RAVE perspective

2015 ◽  
Vol 11 (S317) ◽  
pp. 320-323
Author(s):  
Georges Kordopatis ◽  
Keyword(s):  
Radial Velocity ◽  
Milky Way ◽  
Solar Neighbourhood ◽  
Low Mass Stars ◽  
Medium Resolution ◽  
Low Mass

AbstractThe RAdial Velocity Experiment (RAVE) collected from 2003 to 2013 medium resolution spectra for 5ċ105 low-mass stars of our Galaxy, improving our understanding of the Milky Way evolution and of its properties outside the Solar neighbourhood. This proceeding gives an overview of RAVE results obtained in the last two years.

scholarly journals Radial Velocities and Rotational Velocities of Late-Type Stars in the Coma Ber Cluster

1980 ◽  
Vol 85 ◽  
pp. 243-244
Author(s):  
M. Mayor ◽  
J. C. Mermilliod
Keyword(s):  
Radial Velocity ◽  
Radial Velocities ◽  
Late Type ◽  
Low Mass Stars ◽  
Red Dwarfs ◽  
Low Mass ◽  
The Mean ◽  
Average Dispersion

Stars with spectral types later than or equal to F5V in the Coma Ber cluster have been measured from 1977 to 1979 with the spectrometer CORAVEL (A. Baranne et al. 1980). The aims of this investigation were to clarify the membership based on radial velocity for some faint stars, to study the binarity of the low mass stars of the cluster, and to obtain the distribution of the rotational velocities for the red dwarfs. 391 measurements have been made for 34 stars. The average dispersion over the mean VR of each star is 0.6 kms−1.

scholarly journals Astrometric exoplanet surveys in practice

2015 ◽  
Vol 11 (A29A) ◽  
pp. 217-218
Author(s):  
Johannes Sahlmann
Keyword(s):  
Radial Velocity ◽  
Brown Dwarfs ◽  
Giant Planets ◽  
Low Mass Stars ◽  
Low Mass ◽  
Host Stars

AbstractConversely to the transit photometry and radial velocity methods, the astrometric discovery of exoplanets is still limited by the sensitivity of available instruments. Ground-based surveys are now sensitive to giant planets in orbit around nearby low-mass stars and brown dwarfs. In 2014, ESA's Gaia mission began its survey, which is expected to discover thousands of giant exoplanets by detecting the astrometric orbital motions of the host stars.

scholarly journals Radial velocity studies of cool stars

2014 ◽  
Vol 372 (2014) ◽  
pp. 20130088 ◽  
Author(s):  
Hugh R. A. Jones ◽  
John Barnes ◽  
Mikko Tuomi ◽  
James S. Jenkins ◽  
Guillem Anglada-Escude
Keyword(s):  
Radial Velocity ◽  
Current View ◽  
Velocity Data ◽  
M Dwarfs ◽  
Low Mass Stars ◽  
Robust Detection ◽  
Dwarf Planets ◽  
Low Mass ◽  
M Dwarf ◽  
Radial Velocity Data

Our current view of exoplanets is one derived primarily from solar-like stars with a strong focus on understanding our Solar System. Our knowledge about the properties of exoplanets around the dominant stellar population by number, the so-called low-mass stars or M dwarfs, is much more cursory. Based on radial velocity discoveries, we find that the semi-major axis distribution of M dwarf planets appears to be broadly similar to those around more massive stars and thus formation and migration processes might be similar to heavier stars. However, we find that the mass of M dwarf planets is relatively much lower than the expected mass dependency based on stellar mass and thus infer that planet formation efficiency around low-mass stars is relatively impaired. We consider techniques to overcome the practical issue of obtaining good quality radial velocity data for M dwarfs despite their faintness and sustained activity and emphasize (i) the wavelength sensitivity of radial velocity signals, (ii) the combination of radial velocity data from different experiments for robust detection of small amplitude signals, and (iii) the selection of targets and radial velocity interpretation of late-type M dwarfs should consider H α behaviour.

scholarly journals A HIGH-PRECISION NEAR-INFRARED SURVEY FOR RADIAL VELOCITY VARIABLE LOW-MASS STARS USING CSHELL AND A METHANE GAS CELL

2016 ◽  
Vol 822 (1) ◽  
pp. 40 ◽  
Author(s):  
Jonathan Gagné ◽  
Peter Plavchan ◽  
Peter Gao ◽  
Guillem Anglada-Escude ◽  
Elise Furlan ◽  
...  
Keyword(s):  
Radial Velocity ◽  
High Precision ◽  
Near Infrared ◽  
Gas Cell ◽  
Low Mass Stars ◽  
Methane Gas ◽  
Low Mass ◽  
Infrared Survey

scholarly journals The dynamics of the γ Vel cluster and nearby Vela OB2 association

2020 ◽  
Vol 494 (4) ◽  
pp. 4794-4801 ◽  
Author(s):  
Joseph J Armstrong ◽  
Nicholas J Wright ◽  
R D Jeffries ◽  
R J Jackson
Keyword(s):  
Radial Velocity ◽  
Strong Evidence ◽  
Proper Motions ◽  
Velocity Measurements ◽  
Low Mass Stars ◽  
Data Release ◽  
Low Mass ◽  
Ob Associations

ABSTRACT The kinematics of low-mass stars in nearby OB associations can provide clues about their origins and evolution. Combining the precise positions, proper motions, and parallaxes given in the second Gaia Data Release with radial-velocity measurements obtained with the Hermes spectrograph at the Anglo-Australian Telescope, we have an opportunity to study in detail the kinematics of low-mass stars belonging to the nearby γ Vel cluster and the Vela OB2 association it is projected against. The presence of lithium is used to confirm the youth of our targets. We separate our sample into the cluster and association populations based on the Gaia-ESO Survey membership probabilities their parallaxes, and kinematics. We find strong evidence for expansion in the OB association population with at least 4σ significance along all three axes, though the expansion is notably anisotropic. We discuss these results in the context of cluster and association dispersal theories.

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