scholarly journals TOI-132 b: A short-period planet in the Neptune desert transiting a V = 11.3 G-type star★

2020 ◽  
Vol 493 (1) ◽  
pp. 973-985 ◽  
Author(s):  
Matías R Díaz ◽  
James S Jenkins ◽  
Davide Gandolfi ◽  
Eric D Lopez ◽  
Maritza G Soto ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Velocity Variation ◽  
Planetary Mass ◽  
Radial Velocity Variation ◽  
Short Period ◽  
Low Mass ◽  
Formation And Evolution ◽  
Level 1 ◽  
Atmospheric Mass

ABSTRACT The Neptune desert is a feature seen in the radius-period plane, whereby a notable dearth of short period, Neptune-like planets is found. Here, we report the Transiting Exoplanet Survey Satellite (TESS) discovery of a new short-period planet in the Neptune desert, orbiting the G-type dwarf TYC 8003-1117-1 (TOI-132). TESS photometry shows transit-like dips at the level of ∼1400 ppm occurring every ∼2.11 d. High-precision radial velocity follow-up with High Accuracy Radial Velocity Planet Searcher confirmed the planetary nature of the transit signal and provided a semi-amplitude radial velocity variation of 11.38 $^{+0.84}_{-0.85}$ m s−1, which, when combined with the stellar mass of 0.97 ± 0.06 M⊙, provides a planetary mass of 22.40$^{+1.90}_{-1.92}$ M⊕. Modelling the TESS light curve returns a planet radius of 3.42$^{+0.13}_{-0.14}$ R⊕, and therefore the planet bulk density is found to be 3.08$^{+0.44}_{-0.46}$ g cm−3. Planet structure models suggest that the bulk of the planet mass is in the form of a rocky core, with an atmospheric mass fraction of 4.3$^{+1.2}_{-2.3}$ per cent. TOI-132 b is a TESS Level 1 Science Requirement candidate, and therefore priority follow-up will allow the search for additional planets in the system, whilst helping to constrain low-mass planet formation and evolution models, particularly valuable for better understanding of the Neptune desert.

scholarly journals HS 2237+8154: A New Pre-CV just above the Period Gap

2004 ◽  
Vol 194 ◽  
pp. 271-271
Author(s):  
B. T. Gänsicke ◽  
S. Araujo-Betancor ◽  
H.-J. Hagen ◽  
E. T. Harlaftis ◽  
S. Kitsionas ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Orbital Period ◽  
Velocity Variation ◽  
Cataclysmic Variable ◽  
Evolutionary State ◽  
Radial Velocity Variation

We report follow-up observations of the new pre-cataclysmic variable HS 2237+8154, identified from the Hamburg Quasar Survey. The orbital period derived from ellipsoidal modulation observed in the iR-band as well as from the Hα radial velocity variation is orb = 178.10 ± 0.08 min. We briefly discuss the evolutionary state of this system.

scholarly journals Activity-Induced Radial Velocity Variation of M Dwarf Stars

2012 ◽  
Vol 8 (S293) ◽  
pp. 197-200
Author(s):  
Jan Marie Andersen ◽  
Heidi Korhonen
Keyword(s):  
Radial Velocity ◽  
Magnetic Activity ◽  
Velocity Variation ◽  
M Dwarfs ◽  
Dwarf Stars ◽  
Highly Active ◽  
Radial Velocity Variation ◽  
Low Mass ◽  
M Dwarf Stars ◽  
M Dwarf

AbstractStellar magnetic activity manifests itself in a variety of ways including starspots–cool, dark regions on the stellar surface. Starspots can cause variations (‘jitter’) in spectral line-profiles which can mimic the radial velocity (RV) variations caused by an orbiting planet, or create RV noise that can drown out a planetary signature. Cool, low-mass M dwarf stars can be highly active, which can make detection of potentially habitable planets around these stars difficult. We investigate radial velocity variations caused by different activity (spot) patterns on M dwarf stars in order to determine the limits of detectability for small planets orbiting active M dwarfs. We report on our progress toward the aim of answering the following questions: What types of spot patterns are realistic for M dwarf stars? What effect will spots have on M dwarf RV measurements? Can jitter from M dwarf spots mimic planetary signals? What is the ideal observing wavelength to reduce M dwarf jitter?

Short-Period Radial-Velocity Variation of 48 Librae.

1963 ◽  
Vol 137 ◽  
pp. 1310 ◽  
Author(s):  
Adela E. Ringuelet-Kaswalder
Keyword(s):  
Radial Velocity ◽  
Velocity Variation ◽  
Radial Velocity Variation ◽  
Short Period

scholarly journals Exoplanet mass estimation for a sample of targets for the Ariel mission

2021 ◽  
Author(s):  
J. R. Barnes ◽  
C. A. Haswell
Keyword(s):  
Radial Velocity ◽  
Input Parameter ◽  
Noise Sources ◽  
Time Commitment ◽  
Low Mass ◽  
Time Required ◽  
Fixed Input ◽  
The Impact ◽  
Quadrature Sampling

AbstractAriel’s ambitious goal to survey a quarter of known exoplanets will transform our knowledge of planetary atmospheres. Masses measured directly with the radial velocity technique are essential for well determined planetary bulk properties. Radial velocity masses will provide important checks of masses derived from atmospheric fits or alternatively can be treated as a fixed input parameter to reduce possible degeneracies in atmospheric retrievals. We quantify the impact of stellar activity on planet mass recovery for the Ariel mission sample using Sun-like spot models scaled for active stars combined with other noise sources. Planets with necessarily well-determined ephemerides will be selected for characterisation with Ariel. With this prior requirement, we simulate the derived planet mass precision as a function of the number of observations for a prospective sample of Ariel targets. We find that quadrature sampling can significantly reduce the time commitment required for follow-up RVs, and is most effective when the planetary RV signature is larger than the RV noise. For a typical radial velocity instrument operating on a 4 m class telescope and achieving 1 m s−1 precision, between ~17% and ~ 37% of the time commitment is spent on the 7% of planets with mass Mp < 10 M⊕. In many low activity cases, the time required is limited by asteroseismic and photon noise. For low mass or faint systems, we can recover masses with the same precision up to ~3 times more quickly with an instrumental precision of ~10 cm s−1.

scholarly journals XO-2b: a Prograde Planet with Negligible Eccentricity and an Additional Radial Velocity Variation

2011 ◽  
Vol 63 (6) ◽  
pp. L67-L71 ◽  
Author(s):  
Norio Narita ◽  
Teruyuki Hirano ◽  
Bun'ei Sato ◽  
Hiroki Harakawa ◽  
Akihiko Fukui ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Velocity Variation ◽  
Radial Velocity Variation

scholarly journals WASP-4 transit timing variation from a comprehensive set of 129 transits

2020 ◽  
Vol 496 (1) ◽  
pp. L11-L15 ◽  
Author(s):  
R V Baluev ◽  
E N Sokov ◽  
S Hoyer ◽  
C Huitson ◽  
José A R S da Silva ◽  
...  
Keyword(s):  
Conservative Treatment ◽  
Radial Velocity ◽  
Decay Rate ◽  
High Accuracy ◽  
Light Curves ◽  
Velocity Variation ◽  
Radial Acceleration ◽  
Radial Velocity Variation ◽  
Non Linear ◽  
Doppler Data

ABSTRACT We homogeneously reanalyse 124 transit light curves for the WASP-4 b hot Jupiter. This set involved new observations secured in 2019 and nearly all observations mentioned in the literature, including high-accuracy GEMINI/GMOS transmission spectroscopy of 2011–2014 and TESS observations of 2018. The analysis confirmed a non-linear transit timing variation (TTV) trend with $P/|\dot{P}|\sim \hbox{17-30}$ Myr (1σ range), implying only half of the initial decay rate estimation. The trend significance is at least 3.4σ in the aggressively conservative treatment. Possible radial acceleration due to unseen companions is not revealed in Doppler data covering seven years 2007–2014, and radial acceleration of −15 m s−1 yr−1 reported in a recent preprint by another team is not confirmed. If present, it is a very non-linear radial velocity variation. Assuming that the entire TTV is tidal in nature, the tidal quality factor $Q_\star ^{\prime }\sim \hbox{(4.5-8.5)}\times 10^4$ does not reveal a convincing disagreement with available theory predictions.

The Cepheid Variable S. Sagittae. I. The Radial-Velocity Variation.

1952 ◽  
Vol 116 ◽  
pp. 348 ◽  
Author(s):  
G. H. Herbig ◽  
J. H. Moore
Keyword(s):  
Radial Velocity ◽  
Velocity Variation ◽  
Radial Velocity Variation

scholarly journals Disentangling planetary orbits from stellar activity in radial-velocity surveys

2014 ◽  
Vol 13 (2) ◽  
pp. 155-157 ◽  
Author(s):  
R. D. Haywood ◽  
A. Collier Cameron ◽  
D. Queloz ◽  
S.C.C. Barros ◽  
M. Deleuil ◽  
...  
Keyword(s):  
Radial Velocity ◽  
High Accuracy ◽  
Stellar Surface ◽  
Stellar Activity ◽  
The Earth ◽  
Planetary Orbits ◽  
Low Mass ◽  
Do So

AbstractThe majority of extra-solar planets have been discovered (or confirmed after follow-up) through radial-velocity (RV) surveys. Using ground-based spectrographs such as High Accuracy Radial Velocity Planetary Search (HARPS) and HARPS-North, it is now possible to detect planets that are only a few times the mass of the Earth. However, the presence of dark spots on the stellar surface produces RV signals that are very similar in amplitude to those caused by orbiting low-mass planets. Disentangling these signals has thus become the biggest challenge in the detection of Earth-mass planets using RV surveys. To do so, we use the star's lightcurve to model the RV variations produced by spots. Here we present this method and show the results of its application to CoRoT-7.

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