Radial velocity confirmation of Kepler-91 b

Lillo-Box, J.; Barrado, D.; Henning, Th.; Mancini, L.; Ciceri, S.; Figueira, P.; Santos, N. C.; Aceituno, J.; Sánchez, S. F.

doi:10.1051/0004-6361/201424587

Cited by 38 publications

(21 citation statements)

References 28 publications

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“…This object joins a sample of only five other known transiting planets hosted by highly evolved stars (Huber et al 2013a;Lillo-Box et al 2014;Barclay et al 2015;Ciceri et al 2015;Quinn et al 2015;Van Eylen et al 2016). The high metallicity of the host star is also characteristic of the close-in gas giant planet population, suggesting that this system may be simply a successor to such "hot Jupiter" systems.…”

Section: Is K2-97b Inflated?mentioning

confidence: 59%

K2-97b: A (RE-?)INFLATED PLANET ORBITING A RED GIANT STAR

et al. 2016

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Strongly irradiated giant planets are observed to have radii larger than thermal evolution models predict. Although these inflated planets have been known for over 15 years, it is unclear whether their inflation is caused by thedeposition of energy from the host staror theinhibited cooling of the planet. These processes can be distinguished if the planet becomes highly irradiated only when the host star evolves onto the red giant branch. We report the discovery of K2-97b, a 1.31±0.11 R J , 1.10±0.11 M J planet orbiting a 4.20±0.14 R e , 1.16±0.12 M e red giant star with an orbital period of 8.4 days. We precisely constrained stellar and planetary parameters by combining asteroseismology, spectroscopy, and granulation noise modeling along with transit and radial velocity measurements. The uncertainty in planet radius is dominated by systematic differences in transit depth, which we measure to be up to 30% between different light-curve reduction methods. Our calculations indicate the incident flux on this planet was -+ 60140 times the incident flux on Earth, while the star was on the main sequence. Previous studies suggest that this incident flux is insufficient to delay planetary cooling enough to explain the present planet radius. This system thus provides the first evidence that planets may be inflated directly by incident stellar radiation rather than by delayed loss of heat from formation. Further studies of planets around red giant branch stars will confirm or contradict this hypothesisand may reveal a new class of re-inflated planets.

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Section: Is K2-97b Inflated?mentioning

confidence: 59%

K2-97b: A (RE-?)INFLATED PLANET ORBITING A RED GIANT STAR

et al. 2016

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“…Detections of these companions have become ⋆ E-mail:d.veras@warwick.ac.uk more robust with the combined efforts of Doppler radial velocity observations and transit-based photometry (Lillo-Box et al 2014;Ciceri et al 2015;Ortiz et al 2015). Some GB stars contain multiple planets (e.g.…”

Section: Importance Of Post-ms Planetary Systemsmentioning

confidence: 99%

The orbital evolution of asteroids, pebbles and planets from giant branch stellar radiation and winds

Veras¹,

Eggl²,

Gänsicke³

2015

Monthly Notices of the Royal Astronomical Society

104

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The discovery of over 50 planets around evolved stars and more than 35 debris discs orbiting white dwarfs highlight the increasing need to understand small body evolution around both early and asymptotic giant branch (GB) stars. Pebbles and asteroids are susceptible to strong accelerations from the intense luminosity and winds of GB stars. Here, we establish equations that can model time-varying GB stellar radiation, wind drag and mass loss. We derive the complete three-dimensional equations of motion in orbital elements due to (1) the Epstein and Stokes regimes of stellar wind drag, (2) Poynting-Robertson drag, and (3) the Yarkovsky drift with seasonal and diurnal components. We prove through averaging that the potential secular eccentricity and inclination excitation due to Yarkovsky drift can exceed that from PoyntingRobertson drag and radiation pressure by at least three orders of magnitude, possibly flinging asteroids which survive YORP spin-up into a widely dispersed cloud around the resulting white dwarf. The GB Yarkovsky effect alone may change an asteroid's orbital eccentricity by ten per cent in just one Myr. Damping perturbations from stellar wind drag can be just as extreme, but are strongly dependent on the highly uncertain local gas density and mean free path length. We conclude that GB radiative and wind effects must be considered when modelling the post-main-sequence evolution of bodies smaller than about 1000 km.

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“…We used the theoretical equivalency between maximum likelihood and cross-correlation presented in Zucker (2003) to match the observed spectrum to a synthetic template of the same spectral type. This RV extraction process is fully described in Lillo-Box et al (2014b).…”

Section: Cafe Observations and Data Reductionmentioning

confidence: 99%

Eclipsing binaries and fast rotators in theKeplersample

Lillo-Box

Barrado

Mancini

et al. 2015

A&A

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Context. The Kepler mission has searched for planetary transits in more than two hundred thousand stars by obtaining very accurate photometric data over a long period of time. Among the thousands of detected candidates, the planetary nature of around 15% has been established or validated by different techniques. But additional data are needed to characterize the rest of the candidates and reject other possible configurations. Aims. We started a follow-up program to validate, confirm, and characterize some of the planet candidates. In this paper we present the radial velocity analysis of those that present large variations, which are compatible with being eclipsing binaries. We also study those showing high rotational velocities, which prevents us from reaching the necessary precision to detect planetary-like objects. Methods. We present new radial velocity results for 13 Kepler objects of interest (KOIs) obtained with the CAFE spectrograph at the Calar Alto Observatory and analyze their high-spatial resolution (lucky) images obtained with AstraLux and the Kepler light curves of some interesting cases. Results. We have found five spectroscopic and eclipsing binaries (group A). Among them, the case of KOI-3853 is of particular interest. This system is a new example of the so-called heartbeat stars, showing dynamic tidal distortions in the Kepler light curve. We have also detected duration and depth variations of the eclipse. We suggest possible scenarios to explain such an effect, including the presence of a third substellar body possibly detected in our radial velocity analysis. We also provide upper mass limits to the transiting companions of six other KOIs with high rotational velocities (group B). This property prevents the radial velocity method from achieving the necessary precision to detect planetary-like masses. Finally, we analyze the large radial velocity variations of two other KOIs, which are incompatible with the presence of planetary-mass objects (group C). These objects are likely to be stellar binaries. However, a longer timespan is needed to complete their characterization.

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Radial velocity confirmation of Kepler-91 b

Cited by 38 publications

References 28 publications

K2-97b: A (RE-?)INFLATED PLANET ORBITING A RED GIANT STAR

K2-97b: A (RE-?)INFLATED PLANET ORBITING A RED GIANT STAR

The orbital evolution of asteroids, pebbles and planets from giant branch stellar radiation and winds

Eclipsing binaries and fast rotators in theKeplersample

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