Evidence for a spectroscopic direct detection of reflected light from 51 Pegasi b

Martins, J. H. C.; Santos, N. C.; Figueira, P.; Faria, J. P.; Montalto, M.; Boisse, I.; Ehrenreich, D.; Lovis, C.; Mayor, M.; Melo, C.; Pepe, F.; Sousa, S. G.; Udry, S.; Cunha, Diana

doi:10.1051/0004-6361/201425298

Cited by 67 publications

(141 citation statements)

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“…An even higher value may be expected at longer wavelengths. Such signals should be easily detectable with recent instruments such as SPHERE or using a detailed spectroscopic analysis (Brogi et al 2012;Snellen et al 2014;Martins et al 2015). We note that the projected distance on the sky between the star and the planet is about 0.14 arcsec at apastron.…”

Section: A System Full Of Potentialmentioning

confidence: 82%

An extreme planetary system around HD 219828

Santos

Santerne

Faria

et al. 2016

A&A

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Context. With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. This wide diversity provides fundamental clues to the processes of planet formation and evolution. Aims. We present a full investigation of the HD 219828 system, a bright metal-rich star for which a hot Neptune has previously been detected. Methods. We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD 219828. The spectra were used to characterise the star and its chemical abundances, as well as to check for spurious, activity induced signals. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. Results. We announce the discovery of a long period (P = 13.1 yr) massive (m sin i = 15.1 M Jup ) companion (HD 219828 c) in a very eccentric orbit (e = 0.81). The same data confirms the existence of a hot Neptune, HD 219828 b, with a minimum mass of 21 M ⊕ and a period of 3.83 days. The dynamical analysis shows that the system is stable, and that the equilibrium eccentricity of planet b is close to zero. Conclusions. The HD 219828 system is extreme and unique in several aspects. First, ammong all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like HD 219828, with a hot Neptune and a long-period massive companion are more frequent than similar systems with a hot Jupiter instead. This suggests that the formation of hot Neptunes follows a different path than the formation of their hot jovian counterparts. The high mass, long period, and eccentricity of HD 219828 c also make it a good target for Gaia astrometry as well as a potential target for atmospheric characterisation, using direct imaging or high-resolution spectroscopy. Astrometric observations will allow us to derive its real mass and orbital configuration. If a transit of HD 219828 b is detected, we will be able to fully characterise the system, including the relative orbital inclinations. With a clearly known mass, HD 219828 c may become a benchmark object for the range in between giant planets and brown dwarfs.

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Section: A System Full Of Potentialmentioning

confidence: 82%

An extreme planetary system around HD 219828

Santos

Santerne

Faria

et al. 2016

A&A

Self Cite

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“…), inconsistent with a Lambertian sphere (i.e., isotropic reflection in all directions) implying a strongly backscattering atmosphere. The CCF derived by Martins et al (2015) for 51 Peg b was also significantly broadened to a . The Gaussian has a = FWHM 5.6 km s −1 .…”

Section: Atmospheric Properties Of the Planetmentioning

confidence: 90%

“…We also note that the orbital solution used by Martins et al (2015) assumed a fixed, zero eccentricity, but did not explore the systemic velocity parameter space, which may have led to a stronger signal being detected at the offset V sys we found in Section 3.2.1. If the optical data can be analyzed such that they do not induce the excess broadening seen in Martins et al (2015), we can compare the detected planet V sys at optical and infrared wavelengths.…”

Section: Atmospheric Properties Of the Planetmentioning

confidence: 93%

Discovery of Water at High Spectral Resolution in the Atmosphere of 51 Peg b

Birkby¹,

Kok²,

Brogi³

et al. 2017

177

240

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We report the detection of water absorption features in the day side spectrum of the first-known hot Jupiter, 51 Peg b, confirming the star-planet system to be a double-lined spectroscopic binary. We use high-resolution ( » R 100,000), m 3.2 m spectra taken with CRIRES/VLT to trace the radial-velocity shift of the water features in the planet's day side atmosphere during 4 hr of its 4.23 day orbit after superior conjunction. We detect the signature of molecular absorption by water at a significance of J , placing it at the transition boundary between Jovian and Neptunian worlds. We determine upper and lower limits on the orbital inclination of the system of  < <  i 70 8 2.2. We also provide an updated orbital solution for 51 Peg b, using an extensive set of 639 stellar radial velocities measured between 1994 and 2013, finding no significant evidence of an eccentric orbit. We find no evidence of significant absorption or emission from other major carbon-bearing molecules of the planet, including methane and carbon dioxide. The atmosphere is non-inverted in the temperature-pressure region probed by these observations. The deepest absorption lines reach an observed relative contrast of´-0.9 10 3 with respect to the host star continuum flux at an angular separation of 3 milliarcseconds. This work is consistent with a previous tentative report of K-band molecular absorption for 51 Peg b by Brogi et al.

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“…Since the discovery of 51 Peg b (Mayor & Queloz 1995), the radial velocity (RV) technique has proven indispensable for exoplanet discovery. Hundreds of exoplanets have been revealed by measuring the Doppler wobble of the exoplanet host star (Wright et al 2012), principally at visible wavelengths.…”

Section: Introductionmentioning

confidence: 99%

“…By detecting the RV variation of a planet's atmospheric lines in about six hours of observations on single nights, further work has detected the dayside and nightside thermal spectra of various transiting and non-transiting hot Jupiters, reporting detections of water and carbon monoxide, as well as the presence of winds and measurements of the length of day (Snellen et al 2010;Brogi et al 2012Brogi et al , 2013Brogi et al , 2014Brogi et al , 2016Rodler et al 2012;Birkby et al 2013;de Kok et al 2013;Snellen et al 2014;Schwarz et al 2015). With HARPS, Martins et al (2015) recently observed the reflected light spectrum of 51 Peg b in a similar manner, combining 12.5 hr of data taken over seven nights when the full dayside of the planet was observable. Lockwood et al (2014) studied the hot Jupiter tau Boo b using Keck NIRSPEC (Near InfraRed SPECtrometer), confirmed the CRIRES measurement of the planet's Keplerian orbital velocity, and detected water vapor in the atmosphere of a non-transiting exoplanet for the first time.…”

Section: Introductionmentioning

confidence: 99%

EVIDENCE FOR THE DIRECT DETECTION OF THE THERMAL SPECTRUM OF THE NON-TRANSITING HOT GAS GIANT HD 88133 b

Piskorz

Benneke

Crockett

et al. 2016

ApJ

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We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution nearinfrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant's atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth's atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L-band observations and three epochs of Keck NIRSPEC K-band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross-correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of the Keplerian orbital velocity of 40±15 km s , and an atmosphere opacity structure at high dispersion dominated by water vapor. This, combined with 11 years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.

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Evidence for a spectroscopic direct detection of reflected light from 51 Pegasi b

Cited by 67 publications

References 60 publications

An extreme planetary system around HD 219828

An extreme planetary system around HD 219828

Discovery of Water at High Spectral Resolution in the Atmosphere of 51 Peg b

EVIDENCE FOR THE DIRECT DETECTION OF THE THERMAL SPECTRUM OF THE NON-TRANSITING HOT GAS GIANT HD 88133 b

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