Brown dwarf companion with a period of 4.6 yr interacting with the hot Jupiter CoRoT-20 b

We report the discovery of an additional substellar companion in the CoRoT-20 system based on six years of HARPS and SOPHIE radial velocity follow-up. CoRoT-20 c has a minimum mass of 17 ± 1 MJup and orbits the host star in 4.59 ± 0.05 yr, with an orbital eccentricity of 0.60 ± 0.03. This is the first identified system with an eccentric hot Jupiter and an eccentric massive companion. The discovery of the latter might be an indication of the migration mechanism of the hot Jupiter, via the Lidov–Kozai effect. We explore the parameter space to determine which configurations would trigger this type of interactions.

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Direct Imaging Of Long Period Radial Velocity Targets With NICI

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313007904 ◽

2013 ◽

Vol 8 (S299) ◽

pp. 66-67

Author(s):

Graeme S. Salter ◽

Chris G. Tinney ◽

Robert A. Wittenmyer ◽

James S. Jenkins ◽

Hugh R.A. Jones ◽

...

Keyword(s):

Radial Velocity ◽

Near Infrared ◽

Minimum Mass ◽

Post Processing ◽

Velocity Measurements ◽

Brown Dwarf ◽

Direct Imaging ◽

Parameter Spaces ◽

Long Period ◽

Imaging Parameter

AbstractWe are finally entering an era where radial velocity and direct imaging parameter spaces are starting to overlap. Radial velocity measurements provide us with a minimum mass for an orbiting companion (the mass as a function of the inclination of the system). By following up these long period radial velocity detections with direct imaging we can determine whether a trend seen is due to an orbiting planet at low inclination or an orbiting brown dwarf at high inclination. In the event of a non-detection we are still able to put a limit on the maximum mass of the orbiting body. The Anglo-Australian Planet Search is one of the longest baseline radial velocity planet searches in existence, amongst its targets are many that show long period trends in the data. Here we present our direct imaging survey of these objects with our results to date. ADI Observations have been made using NICI (Near Infrared Coronagraphic Imager) on Gemini South and analysed using an in house, LOCI-like, post processing.

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Determining the true mass of radial-velocity exoplanets with Gaia

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039168 ◽

2020 ◽

Vol 645 ◽

pp. A7

Author(s):

F. Kiefer ◽

G. Hébrard ◽

A. Lecavelier des Etangs ◽

E. Martioli ◽

S. Dalal ◽

...

Keyword(s):

Radial Velocity ◽

Extreme Values ◽

Minimum Mass ◽

Brown Dwarf ◽

True Nature ◽

Astronomical Object ◽

Orbital Periods ◽

True Mass

Mass is one of the most important parameters for determining the true nature of an astronomical object. Yet, many published exoplanets lack a measurement of their true mass, in particular those detected as a result of radial-velocity (RV) variations of their host star. For those examples, only the minimum mass, or m sin i, is known, owing to the insensitivity of RVs to the inclination of the detected orbit compared to the plane of the sky. The mass that is given in databases is generally that of an assumed edge-on system (~90°), but many other inclinations are possible, even extreme values closer to 0° (face-on). In such a case, the mass of the published object could be strongly underestimated by up to two orders of magnitude. In the present study, we use GASTON, a recently developed tool taking advantage of the voluminous Gaia astrometric database to constrain the inclination and true mass of several hundreds of published exoplanet candidates. We find nine exoplanet candidates in the stellar or brown dwarf (BD) domain, among which six were never characterized. We show that 30 Ari B b, HD 141937 b, HD 148427 b, HD 6718 b, HIP 65891 b, and HD 16760 b have masses larger than 13.5 MJ at 3σ. We also confirm the planetary nature of 27 exoplanets, including HD 10180 c, d and g. Studying the orbital periods, eccentricities, and host-star metallicities in the BD domain, we found distributions with respect to true masses consistent with other publications. The distribution of orbital periods shows of a void of BD detections below ~100 d, while eccentricity and metallicity distributions agree with a transition between BDs similar to planets and BDs similar to stars in the range 40–50 MJ.

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Testing exoplanet evaporation with multitransiting systems

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3435 ◽

2019 ◽

Vol 491 (4) ◽

pp. 5287-5297 ◽

Cited By ~ 15

Author(s):

James E Owen ◽

Beatriz Campos Estrada

Keyword(s):

Radial Velocity ◽

Excellent Agreement ◽

Minimum Mass ◽

Mass Measurements ◽

Evolutionary Pathway ◽

X Ray ◽

Transiting Planets ◽

Formation History

ABSTRACT The photoevaporation model is one of the leading explanations for the evolution of small, close-in planets and the origin of the radius-valley. However, without planet mass measurements, it is challenging to test the photoevaporation scenario. Even if masses are available for individual planets, the host star’s unknown EUV/X-ray history makes it difficult to assess the role of photoevaporation. We show that systems with multiple transiting planets are the best in which to rigorously test the photoevaporation model. By scaling one planet to another in a multitransiting system, the host star’s uncertain EUV/X-ray history can be negated. By focusing on systems that contain planets that straddle the radius-valley, one can estimate the minimum masses of planets above the radius-valley (and thus are assumed to have retained a voluminous hydrogen/helium envelope). This minimum mass is estimated by assuming that the planet below the radius-valley entirely lost its initial hydrogen/helium envelope, then calculating how massive any planet above the valley needs to be to retain its envelope. We apply this method to 104 planets above the radius gap in 73 systems for which precise enough radii measurements are available. We find excellent agreement with the photoevaporation model. Only two planets (Kepler-100c and 142c) appear to be inconsistent, suggesting they had a different formation history or followed a different evolutionary pathway to the bulk of the population. Our method can be used to identify TESS systems that warrant radial-velocity follow-up to further test the photoevaporation model. The software to estimate minimum planet masses is publicly available at https://github.com/jo276/EvapMass.

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Radial velocity follow-up of GJ1132 with HARPS

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731884 ◽

2018 ◽

Vol 618 ◽

pp. A142 ◽

Cited By ~ 20

Author(s):

X. Bonfils ◽

J.-M. Almenara ◽

R. Cloutier ◽

A. Wünsche ◽

N. Astudillo-Defru ◽

...

Keyword(s):

Radial Velocity ◽

A Priori ◽

Equilibrium Temperature ◽

Correlated Noise ◽

Minimum Mass ◽

Stellar Rotation ◽

Stellar Activity ◽

Orbital Parameters ◽

The Status

The source GJ1132 is a nearby red dwarf known to host a transiting Earth-size planet. After its initial detection, we pursued an intense follow-up with the HARPS velocimeter. We now confirm the detection of GJ1132b with radial velocities alone. We refined its orbital parameters, and in particular, its mass (mb = 1.66 ± 0.23 M⊕), density (ρb = 6.3 ± 1.3 g cm−3), and eccentricity (eb < 0.22; 95%). We also detected at least one more planet in the system. GJ1132c is a super-Earth with period Pc = 8.93 ± 0.01 days and minimum mass mc sinic = 2.64 ± 0.44 M⊕. Receiving about 1.9 times more flux than Earth in our solar system, its equilibrium temperature is that of a temperate planet (Teq = 230−300 K for albedos A = 0.75 − 0.00), which places GJ1132c near the inner edge of the so-called habitable zone. Despite an a priori favorable orientation for the system, Spitzer observations reject most transit configurations, leaving a posterior probability <1% that GJ1132c transits. GJ1132(d) is a third signal with period Pd = 177 ± 5 days attributed to either a planet candidate with minimum mass md sin id = 8.4−2.5+1.7 M⊕ or stellar activity. Its Doppler signal is the most powerful in our HARPS time series but appears on a timescale where either the stellar rotation or a magnetic cycle are viable alternatives to the planet hypothesis. On the one hand, the period is different than that measured for the stellar rotation (~125 days), and a Bayesian statistical analysis we performed with a Markov chain Monte Carlo and Gaussian processes demonstrates that the signal is better described by a Keplerian function than by correlated noise. On the other hand, periodograms of spectral indices sensitive to stellar activity show power excess at similar periods to that of this third signal, and radial velocity shifts induced by stellar activity can also match a Keplerian function. We, therefore, prefer to leave the status of GJ1132(d) undecided.

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

Experimental Astronomy ◽

10.1007/s10686-021-09758-0 ◽

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.

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Tidally induced stellar oscillations: converting modelled oscillations excited by hot Jupiters into observables

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3394 ◽

2020 ◽

Vol 500 (2) ◽

pp. 2711-2731

Author(s):

Andrew Bunting ◽

Caroline Terquem

Keyword(s):

Radial Velocity ◽

Orbital Period ◽

Planetary Systems ◽

Velocity Signal ◽

Convective Flux ◽

Hot Jupiters ◽

Stellar Oscillations ◽

Orbital Periods ◽

Hot Jupiter

ABSTRACT We calculate the conversion from non-adiabatic, non-radial oscillations tidally induced by a hot Jupiter on a star to observable spectroscopic and photometric signals. Models with both frozen convection and an approximation for a perturbation to the convective flux are discussed. Observables are calculated for some real planetary systems to give specific predictions. The photometric signal is predicted to be proportional to the inverse square of the orbital period, P−2, as in the equilibrium tide approximation. However, the radial velocity signal is predicted to be proportional to P−1, and is therefore much larger at long orbital periods than the signal corresponding to the equilibrium tide approximation, which is proportional to P−3. The prospects for detecting these oscillations and the implications for the detection and characterization of planets are discussed.

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TOI-150b and TOI-163b: two transiting hot Jupiters, one eccentric and one inflated, revealed by TESS near and at the edge of the JWST CVZ

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2433 ◽

2019 ◽

Vol 490 (1) ◽

pp. 1094-1110 ◽

Cited By ~ 3

Author(s):

Diana Kossakowski ◽

Néstor Espinoza ◽

Rafael Brahm ◽

Andrés Jordán ◽

Thomas Henning ◽

...

Keyword(s):

High Resolution ◽

Time Scale ◽

High Resolution Spectroscopy ◽

Spin Orbit ◽

Eccentric Orbit ◽

Hot Jupiters ◽

Eclipse Observations ◽

James Webb Space Telescope ◽

Hot Jupiter

Abstract We present the discovery of TYC9191-519-1b (TOI-150b, TIC 271893367) and HD271181b (TOI-163b, TIC 179317684), two hot Jupiters initially detected using 30-min cadence Transiting Exoplanet Survey Satellite (TESS) photometry from Sector 1 and thoroughly characterized through follow-up photometry (CHAT, Hazelwood, LCO/CTIO, El Sauce, TRAPPIST-S), high-resolution spectroscopy (FEROS, CORALIE), and speckle imaging (Gemini/DSSI), confirming the planetary nature of the two signals. A simultaneous joint fit of photometry and radial velocity using a new fitting package juliet reveals that TOI-150b is a $1.254\pm 0.016\ \rm {R}_ \rm{J}$, massive ($2.61^{+0.19}_{-0.12}\ \rm {M}_ \rm{J}$) hot Jupiter in a 5.857-d orbit, while TOI-163b is an inflated ($R_ \rm{P}$ = $1.478^{+0.022}_{-0.029} \,\mathrm{ R}_ \rm{J}$, $M_ \rm{P}$ = $1.219\pm 0.11 \, \rm{M}_ \rm{J}$) hot Jupiter on a P = 4.231-d orbit; both planets orbit F-type stars. A particularly interesting result is that TOI-150b shows an eccentric orbit ($e=0.262^{+0.045}_{-0.037}$), which is quite uncommon among hot Jupiters. We estimate that this is consistent, however, with the circularization time-scale, which is slightly larger than the age of the system. These two hot Jupiters are both prime candidates for further characterization – in particular, both are excellent candidates for determining spin-orbit alignments via the Rossiter–McLaughlin (RM) effect and for characterizing atmospheric thermal structures using secondary eclipse observations considering they are both located closely to the James Webb Space Telescope (JWST) Continuous Viewing Zone (CVZ).

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The Hubble PanCET program: Transit and Eclipse Spectroscopy of the Hot-Jupiter WASP-74b

The Astronomical Journal ◽

10.3847/1538-3881/ac3008 ◽

2021 ◽

Vol 162 (6) ◽

pp. 271

Author(s):

Guangwei Fu ◽

Drake Deming ◽

Erin May ◽

Kevin Stevenson ◽

David K. Sing ◽

...

Keyword(s):

Rayleigh Scattering ◽

Hubble Space Telescope ◽

Absorption Feature ◽

Spectral Library ◽

Data Set ◽

Space Telescope ◽

Methane Absorption ◽

James Webb Space Telescope ◽

Hot Jupiter

Abstract Planets are like children with each one being unique and special. A better understanding of their collective properties requires a deeper understanding of each planet. Here we add the transit and eclipse spectra of hot-Jupiter WASP-74b into the ever growing data set of exoplanet atmosphere spectral library. With six transits and three eclipses using the Hubble Space Telescope and Spitzer Space Telescope (Spitzer), we present the most complete and precise atmospheric spectra of WASP-74b. We found no evidence for TiO/VO nor super-Rayleigh scattering reported in previous studies. The transit shows a muted water feature with strong Rayleigh scattering extending into the infrared. The eclipse shows a featureless blackbody-like WFC3/G141 spectrum and a weak methane absorption feature in the Spitzer 3.6 μm band. Future James Webb Space Telescope follow-up observations are needed to confirm these results.

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