scholarly journals A HET search for planets around evolved stars

2007 ◽  
Vol 3 (S249) ◽  
pp. 43-47 ◽  
Author(s):  
Andrzej Niedzielski ◽  
Alex Wolszczan
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Main Sequence ◽  
Experimental Basis ◽  
Velocity Measurements ◽  
Intermediate Mass ◽  
Instability Strip ◽  
Stellar Spectra ◽  
Evolved Stars ◽  
Planetary Mass

AbstractWe present our ongoing survey of ∼1000 GK-giants with the 9.2-m Hobby-Eberly Telescope in search for planets around evolved stars. The stars selected for this survey are brighter than 11 mag and are located in the section of the HR-diagram, which is approximately delimited by the main sequence, the instability strip, and the coronal dividing line. We use the High Resolution Spectrograph to obtain stellar spectra for radial velocity measurements with a 4-6 m s−1 precision. So far, the survey has discovered a planetary-mass companion to the K0-giant HD 17092, and it has produced a number of plausible planet candidates around other stars. Together with other similar efforts, our program provides information on planet formation around intermediate mass main sequence-progenitors and it will create the experimental basis with which to study dynamics of planetary systems around evolving stars.

scholarly journals The Pan-Pacific Planet Search – VIII. Complete results and the occurrence rate of planets around low-luminosity giants

2019 ◽  
Vol 491 (4) ◽  
pp. 5248-5257 ◽  
Author(s):  
Robert A Wittenmyer ◽  
R P Butler ◽  
Jonathan Horner ◽  
Jake Clark ◽  
C G Tinney ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Main Sequence ◽  
Giant Planets ◽  
Occurrence Rate ◽  
Velocity Measurements ◽  
Intermediate Mass ◽  
Giant Stars ◽  
Intermediate Mass Stars ◽  
Final Data ◽  
Solar Type

ABSTRACT Our knowledge of the populations and occurrence rates of planets orbiting evolved intermediate-mass stars lags behind that for solar-type stars by at least a decade. Some radial velocity surveys have targeted these low-luminosity giant stars, providing some insights into the properties of their planetary systems. Here, we present the final data release of the Pan-Pacific Planet Search (PPPS), a 5 yr radial velocity survey using the 3.9 m Anglo-Australian Telescope. We present 1293 precise radial velocity measurements for 129 stars, and highlight 6 potential substellar-mass companions, which require additional observations to confirm. Correcting for the substantial incompleteness in the sample, we estimate the occurrence rate of giant planets orbiting low-luminosity giant stars to be approximately 7.8$^{+9.1}_{-3.3}$ per cent. This result is consistent with the frequency of such planets found to orbit main-sequence A-type stars, from which the PPPS stars have evolved.

scholarly journals A Search for Radial Velocity Oscillations in Procyon

1988 ◽  
Vol 132 ◽  
pp. 83-86
Author(s):  
Ken G. Libbrecht
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Duty Cycle ◽  
New Technique ◽  
Absorption Cell ◽  
Velocity Measurements ◽  
Stellar Spectra ◽  
Iodine Absorption ◽  
A New Technique

I describe here a new technique for precision radial velocity measurements, using an iodine absorption cell in front of the slit of a high resolution spectrograph. A CCD in a continuous readout mode records a timeseries of stellar spectra with a duty cycle of unity. In January 1987, observations were obtained on two clear nights with bad seeing. No oscillations were detected in the data, but the technique shows promise for significantly better results under better conditions.

scholarly journals TESS Giants Transiting Giants. I.: A Noninflated Hot Jupiter Orbiting a Massive Subgiant

2022 ◽  
Vol 163 (2) ◽  
pp. 53
Author(s):  
Nicholas Saunders ◽  
Samuel K. Grunblatt ◽  
Daniel Huber ◽  
Karen A. Collins ◽  
Eric L. N. Jensen ◽  
...  
Keyword(s):  
Main Sequence ◽  
Planetary System ◽  
Scattered Light ◽  
Image Data ◽  
Velocity Measurements ◽  
Main Sequence Stars ◽  
Transiting Planets ◽  
Depth Difference ◽  
Evolved Stars ◽  
Hot Jupiter

Abstract While the population of confirmed exoplanets continues to grow, the sample of confirmed transiting planets around evolved stars is still limited. We present the discovery and confirmation of a hot Jupiter orbiting TOI-2184 (TIC 176956893), a massive evolved subgiant (M ⋆ = 1.53 ± 0.12 M ⊙, R ⋆ = 2.90 ± 0.14 R ⊙) in the Transiting Exoplanet Survey Satellite (TESS) Southern Continuous Viewing Zone. The planet was flagged as a false positive by the TESS Quick-Look Pipeline due to periodic systematics introducing a spurious depth difference between even and odd transits. Using a new pipeline to remove background scattered light in TESS Full Frame Image data, we combine space-based TESS photometry, ground-based photometry, and ground-based radial velocity measurements to report a planet radius of R p = 1.017 ± 0.051 R J and mass of M p = 0.65 ± 0.16 M J . For a planet so close to its star, the mass and radius of TOI-2184b are unusually well matched to those of Jupiter. We find that the radius of TOI-2184b is smaller than theoretically predicted based on its mass and incident flux, providing a valuable new constraint on the timescale of post-main-sequence planet inflation. The discovery of TOI-2184b demonstrates the feasibility of detecting planets around faint (TESS magnitude > 12) post-main-sequence stars and suggests that many more similar systems are waiting to be detected in the TESS FFIs, whose confirmation may elucidate the final stages of planetary system evolution.

scholarly journals Precise Radial Velocity Measurements with a Cassegrain Spectrograph, I: Wavelength calibration

1999 ◽  
Vol 170 ◽  
pp. 63-67
Author(s):  
I. V. Ilyin ◽  
R. Duemmler
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Cross Correlation ◽  
Time Dependent ◽  
Instrumental Effects ◽  
Velocity Measurements ◽  
Echelle Spectrograph ◽  
Optical Telescope ◽  
La Palma ◽  
Observational Strategy

AbstractWe briefly describe the instrumental effects which affect the accuracy of the radial velocity measurements. We have implemented several methods to correct for the instability effects and improve the accuracy of the measurements. These include modifications of the observational strategy and a time-dependent wavelength solution as well as a discussion of the error of the offset from cross-correlation. These methods are applied to observations obtained with the high resolution échelle spectrograph SOFIN mounted at the Cassegrain focus of the alt-azimuth 2.56-m Nordic Optical Telescope, La Palma, Canary Islands.

scholarly journals The Long-term Variation in the RV Tauri Star U Mon

1995 ◽  
Vol 155 ◽  
pp. 409-410 ◽  
Author(s):  
Karen R. Pollard ◽  
P. L. Cottrell
Keyword(s):  
High Resolution ◽  
Light Curve ◽  
Radial Velocity ◽  
Tauri Star ◽  
Short Term ◽  
Instability Strip ◽  
Term Variation ◽  
Velocity Variations

The RV Tauri stars are semiregular pulsating variables located in the brightest part of the Cepheid II instability strip. They have a characteristic light curve of alternating deep and shallow minima. A subset of the RV Tauri stars (the RVb subclass) exhibit long-term (500 to 2600 day) light and radial velocity variations. Although it is well established that the short-term variations are due to pulsations, the long-term behaviour is not well understood.BVRI photometry and high-resolution spectra of U Mon (the brightest member of the RVb subclass) were obtained at the Mt John University Observatory (MJUO) between 1990 Aug and 1994 May. The light and colour curves obtained clearly show the long-term variation in U Mon (Fig. 1(a) and (b)). The reddest colours occur slightly later than the long-term minimum in the light curve. The short-term light and colour variations are ‘damped’ at the long-term minimum.

scholarly journals Masses of the components of SB2 binaries observed with Gaia – V. Accurate SB2 orbits for 10 binaries and masses of the components of 5 binaries

2020 ◽  
Vol 496 (2) ◽  
pp. 1355-1368
Author(s):  
J-L Halbwachs ◽  
F Kiefer ◽  
Y Lebreton ◽  
H M J Boffin ◽  
F Arenou ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Main Sequence ◽  
Spectroscopic Binaries ◽  
Orbital Elements ◽  
Evolved Stars ◽  
The Individual ◽  
The Masses ◽  
Stellar Masses ◽  
Selection Of

ABSTRACT Double-lined spectroscopic binaries (SB2s) are one of the main sources of stellar masses, as additional observations are only needed to give the inclinations of the orbital planes in order to obtain the individual masses of the components. For this reason, we are observing a selection of SB2s using the SOPHIE spectrograph at the Haute-Provence observatory in order to precisely determine their orbital elements. Our objective is to finally obtain masses with an accuracy of the order of one per cent by combining our radial velocity (RV) measurements and the astrometric measurements that will come from the Gaia satellite. We present here the RVs and the re-determined orbits of 10 SB2s. In order to verify the masses, we will derive from Gaia, we obtained interferometric measurements of the ESO VLTI for one of these SB2s. Adding the interferometric or speckle measurements already published by us or by others for four other stars, we finally obtain the masses of the components of five binary stars, with masses ranging from 0.51 to 2.2 solar masses, including main-sequence dwarfs and some more evolved stars whose location in the HR diagram has been estimated.

scholarly journals Transit & RV Observations of Exoplanets by the 1-m Telescope at Weihai

2012 ◽  
Vol 8 (S293) ◽  
pp. 33-35
Author(s):  
Chen Cao ◽  
Dayong Ren ◽  
Dongyang Gao ◽  
Jicheng Zhang ◽  
Nan Song ◽  
...  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Extrasolar Planets ◽  
Physical Parameters ◽  
Velocity Measurements ◽  
Preliminary Results

AbstractBy using the 1-m reflecting telescope at Weihai Observatory of Shandong University, the transit observations of seven stars are carried out to accurately estimate the physical parameters of extrasolar planets. Besides, a new high-resolution spectrograph (WES) was installed on this telescope for radial velocity measurements on exoplanets, we will show some preliminary results.

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 High‐Resolution Far‐Infrared Studies of Intermediate‐Mass Pre–Main‐Sequence Objects

1998 ◽  
Vol 509 (1) ◽  
pp. 324-349 ◽  
Author(s):  
James Di Francesco ◽  
Neal J. Evans II ◽  
Paul M. Harvey ◽  
Lee G. Mundy ◽  
Harold M. Butner
Keyword(s):  
High Resolution ◽  
Main Sequence ◽  
Far Infrared ◽  
Intermediate Mass ◽  
Infrared Studies

scholarly journals Gaia Data Release 2

2018 ◽  
Vol 616 ◽  
pp. A7 ◽  
Author(s):  
C. Soubiran ◽  
G. Jasniewicz ◽  
L. Chemin ◽  
C. Zurbach ◽  
N. Brouillet ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Resolution ◽  
Radial Velocity ◽  
Zero Point ◽  
Velocity Measurements ◽  
Satellite Mission ◽  
Data Release ◽  
Typical Time ◽  
Calibration Device

Aims. The Radial Velocity Spectrometer (RVS) on board the ESA satellite mission Gaia has no calibration device. Therefore, the radial velocity zero point needs to be calibrated with stars that are proved to be stable at a level of 300 m s−1 during the Gaia observations. Methods. We compiled a dataset of ~71 000 radial velocity measurements from five high-resolution spectrographs. A catalogue of 4813 stars was built by combining these individual measurements. The zero point was established using asteroids. Results. The resulting catalogue has seven observations per star on average on a typical time baseline of 6 yr, with a median standard deviation of 15 m s−1. A subset of the most stable stars fulfilling the RVS requirements was used to establish the radial velocity zero point provided in Gaia Data Release 2. The stars that were not used for calibration are used to validate the RVS data.

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