scholarly journals A comprehensive radial velocity error budget for next generation Doppler spectrometers

2016 ◽  
Author(s):  
Samuel Halverson ◽  
Ryan Terrien ◽  
Suvrath Mahadevan ◽  
Arpita Roy ◽  
Chad Bender ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Next Generation ◽  
Error Budget ◽  
Velocity Error

The precision radial velocity error budget for the Gemini High-resolution Optical SpecTrograph (GHOST)

2016 ◽  
Author(s):  
Michael J. Ireland ◽  
Étienne Artigau ◽  
Greg Burley ◽  
Michael Edgar ◽  
Steve Margheim ◽  
...  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Error Budget ◽  
Velocity Error

scholarly journals A radial velocity error budget for single-mode Doppler spectrographs

2018 ◽  
Author(s):  
Andrew Bechter ◽  
Eric Bechter ◽  
Justin R. Crepp ◽  
Jonathan Crass ◽  
David King
Keyword(s):  
Radial Velocity ◽  
Single Mode ◽  
Error Budget ◽  
Velocity Error

scholarly journals NGTS-12b: A sub-Saturn mass transiting exoplanet in a 7.53 day orbit

2020 ◽  
Vol 499 (3) ◽  
pp. 3139-3148
Author(s):  
Edward M Bryant ◽  
Daniel Bayliss ◽  
Louise D Nielsen ◽  
Dimitri Veras ◽  
Jack S Acton ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Effective Temperature ◽  
Low Density ◽  
Next Generation ◽  
Velocity Measurements ◽  
Long Period ◽  
Transmission Spectroscopy ◽  
Stellar Properties

ABSTRACT We report the discovery of the transiting exoplanet NGTS-12b by the Next Generation Transit Survey (NGTS). The host star, NGTS-12, is a V = 12.38 mag star with an effective temperature of Teff = 5690 ± 130 K. NGTS-12b orbits with a period of P = 7.53 d, making it the longest period planet discovered to date by the main NGTS survey. We verify the NGTS transit signal with data extracted from the Transiting Exoplanet Survey Satellite (TESS) full-frame images, and combining the photometry with radial velocity measurements from HARPS and FEROS we determine NGTS-12b to have a mass of 0.208 ± 0.022 MJ and a radius of 1.048 ± 0.032 RJ. NGTS-12b sits on the edge of the Neptunian desert when we take the stellar properties into account, highlighting the importance of considering both the planet and star when studying the desert. The long period of NGTS-12b combined with its low density of just 0.223 ± 0.029 g cm−3 make it an attractive target for atmospheric characterization through transmission spectroscopy with a Transmission Spectroscopy Metric of 89.4.

scholarly journals Next Generation Transit Survey (NGTS)

2013 ◽  
Vol 8 (S299) ◽  
pp. 311-312
Author(s):  
Peter J. Wheatley ◽  
Don L. Pollacco ◽  
Didier Queloz ◽  
Heike Rauer ◽  
Christopher A. Watson ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Internal Structure ◽  
Bulk Composition ◽  
Terrestrial Planets ◽  
Next Generation

AbstractThe Next Generation Transit Survey (NGTS) is a new ground-based survey for transiting exoplanets. Our primary goal is to find the first statistically-significant sample of Neptunes and super-Earths that are bright enough for radial velocity confirmation. By measuring precise masses and radii we will constrain the bulk composition and internal structure of planets that span the transition between the gas giants and terrestrial planets. Our brightest exoplanets will also be suitable for atmospheric characterisation with large facilities such as the VLT, JWST and the E-ELT. NGTS construction began in June 2013, and the survey is due to commence in 2014.

The Impact of Wavelength Step on Radial Velocity Error

2012 ◽  
Vol 239-240 ◽  
pp. 794-797
Author(s):  
Fang Zuo ◽  
A Li Luo
Keyword(s):  
Radial Velocity ◽  
Measurement Method ◽  
Cross Correlation ◽  
Stellar Spectra ◽  
Velocity Error ◽  
Target Spectrum ◽  
Different Types ◽  
The Cross ◽  
The Impact ◽  
Internal Error

Radial velocity (RV) of a star caused by Doppler shift could be easily measured by cross-correlated it’s spectrum with a serial template. Generally, the RV error of a spectrum always is given by the widths of the cross-correlation function of the target spectrum and related template spectrum. RV error comes from many factors, causing from instruments, observation weather, etc.. In this paper, simulation with different types of stellar spectra, which has different temperature, is implemented. The results show that there is an internal error which is not generated by the calculation steps for a given resolution step, for example, 5km/s error exists in the cross-correlation based RV measurement method for resolution about R~2000. The simulation also proves that this error could not be avoided for any type of stars.

The Next Generation Transit Survey

2017 ◽  
Vol 14 (S339) ◽  
pp. 22-22
Author(s):  
M. Burleigh
Keyword(s):  
Radial Velocity ◽  
Mass Determination ◽  
Next Generation ◽  
M Dwarfs ◽  
Early Results ◽  
The Status

AbstractThis talk introduced and described the Next Generation Transit Survey (NGTS), which is a new ground-based transit survey operating at the ESO Paranal Observatory. NGTS has been designed to achieve better photometric precision than previous ground-based surveys; it aims to detect Neptune-sized planets around Sun-like stars, and sub-Neptunes around M dwarfs that are sufficiently bright for radial-velocity confirmation and mass determination. NGTS is also optimised for ground-based follow up of exoplanet candidates from TESS and PLATO. I presented early results from the survey, and described the status of our HARPS radial-velocity and SAAO photometric follow-ups of exoplanet candidates.

scholarly journals A long-period (P = 61.8 d) M5V dwarf eclipsing a Sun-like star from TESS and NGTS

2020 ◽  
Vol 495 (3) ◽  
pp. 2713-2719 ◽  
Author(s):  
Samuel Gill ◽  
Benjamin F Cooke ◽  
Daniel Bayliss ◽  
Louise D Nielsen ◽  
Monika Lendl ◽  
...  
Keyword(s):  
South Africa ◽  
Radial Velocity ◽  
Stellar Evolution ◽  
Orbital Period ◽  
Next Generation ◽  
Velocity Measurements ◽  
Long Period ◽  
Better Than

ABSTRACT The Transiting Exoplanet Survey Satellite has produced a large number of single-transit event candidates which are being monitored by the Next Generation Transit Survey (NGTS). We observed a second epoch for the TIC-231005575 system (Tmag = 12.06 and $T_{\rm eff} = 5500 \pm 85\, \mathrm{ K}$) with NGTS and a third epoch with Las Cumbres Observatory’s telescope in South Africa to constrain the orbital period ($P = 61.777\, \mathrm{ d}$). Subsequent radial velocity measurements with CORALIE revealed the transiting object has a mass of M2 = 0.128 ± 0.003 M⊙, indicating the system is a G-M binary. The radius of the secondary is R2 = 0.154 ± 0.008 R⊙ and is consistent with mesa models of stellar evolution to better than 1σ.

scholarly journals Can we detect the stellar differential rotation of WASP-7 through the Rossiter–McLaughlin observations?

2020 ◽  
Vol 493 (4) ◽  
pp. 5928-5943
Author(s):  
L M Serrano ◽  
M Oshagh ◽  
H M Cegla ◽  
S C C Barros ◽  
N C Santos ◽  
...  
Keyword(s):  
White Noise ◽  
Radial Velocity ◽  
Differential Rotation ◽  
Precise Determination ◽  
Next Generation ◽  
Velocity Signal ◽  
Rotating Star ◽  
Derived Geometry ◽  
Hot Jupiter

ABSTRACT The Rossiter–McLaughlin (RM) effect is the radial velocity signal generated when an object transits a rotating star. Stars rotate differentially and this affects the shape and amplitude of this signal, on a level that can no longer be ignored with precise spectrographs. Highly misaligned planets provide a unique opportunity to probe stellar differential rotation via the RM effect, as they cross several stellar latitudes. In this sense, WASP-7, and its hot Jupiter with a projected misalignment of ∼90°, is one of the most promising targets. The aim of this work is to understand if the stellar differential rotation is measurable through the RM signal for systems with a geometry similar to WASP-7. In this sense, we use a modified version of soap3.0 to explore the main hurdles that prevented the precise determination of the differential rotation of WASP-7. We also investigate whether the adoption of the next generation spectrographs, like ESPRESSO, would solve these issues. Additionally, we assess how instrumental and stellar noise influence this effect and the derived geometry of the system. We found that, for WASP-7, the white noise represents an important hurdle in the detection of the stellar differential rotation, and that a precision of at least 2 m s−1 or better is essential.

scholarly journals A Radar Radial Velocity Dealiasing Algorithm for Radar Data Assimilation and its Evaluation with Observations from Multiple Radar Networks

2019 ◽  
Vol 11 (20) ◽  
pp. 2457
Author(s):  
Guangxin He ◽  
Juanzhen Sun ◽  
Zhuming Ying ◽  
Lejian Zhang
Keyword(s):  
Data Assimilation ◽  
Radial Velocity ◽  
Weather Forecasting ◽  
Weather Radar ◽  
Weather Conditions ◽  
Radar Data ◽  
Next Generation ◽  
Radar Network ◽  
Numerical Weather Forecasting ◽  
Radar Data Assimilation

Automated and accurate radar dealiasing algorithms are very important for their assimilation into operational numerical weather forecasting models. A radar radial velocity dealiasing algorithm aimed at radar data assimilation is introduced and assessed using from several S-band and C-band radar observations under the severe weather conditions of hurricanes, typhoons, and deep continental convection in this paper. This dealiasing algorithm, named automated dealiasing for data assimilation (ADDA), is a further development of the dealiasing algorithm named the China radar network (CINRAD) improved dealiasing algorithm (CIDA), originally developed for China’s CINRAD (China Next Generation Weather Radar) radar network. The improved scheme contains five modules employed to remove noisy data, select the suitable first radial, preserve the convective regions, execute multipass dealiasing in both azimuthal and radial directions and conduct the final local dealiasing with an error check. This new dealiasing algorithm was applied to two hurricane cases, two typhoon cases, and three intense-convection cases that were observed from the CINRAD of China, Taiwan‘s radar network, and NEXRAD (Next Generation Weather Radar) of the U.S. with a continuous period of more than 12 h for each case. The dealiasing results demonstrated that ADDA performed better than CIDA for all selected cases. This algorithm not only produced a high success rate for the S-band radar, but also a reasonable performance for the C-band radar.

The Radial Velocity Measurement and Error Analysis for Low Resolution Spectra

2011 ◽  
Vol 301-303 ◽  
pp. 175-181
Author(s):  
Bin He ◽  
Fang Zuo ◽  
A Li Luo ◽  
Yin Bi Li
Keyword(s):  
Radial Velocity ◽  
Cross Correlation ◽  
Paper Analysis ◽  
Calibration Error ◽  
Velocity Error ◽  
Target Spectrum ◽  
Different Types ◽  
Different Temperatures ◽  
Radial Velocity Measurement ◽  
Instrument Observation

Radial velocity error of the spectra always be given by the widths of the cross-correlation function of the target spectrum and template spectrum. Radial velocity error affected by many inevitable factors, caused by instrument, observation weather, etc.. Another important error comes from calibration, which should be reduced as much as possible. This paper analysis the error based on different temperatures for different types of spectral. The effect of the calibration error to the radial velocity error is also presented.

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