The CORALIE survey for southern extra-solar planets VII

Context. The detection of reflected light from an exoplanet is a difficult technical challenge at optical wavelengths. Even though this signal is expected to replicate the stellar signal, not only is it several orders of magnitude fainter, but it is also hidden among the stellar noise. Aims. We apply a variant of the cross-correlation technique to HARPS observations of 51 Peg to detect the reflected signal from planet 51 Peg b. Methods. Our method makes use of the cross-correlation function (CCF) of a binary mask with high-resolution spectra to amplify the minute planetary signal that is present in the spectra by a factor proportional to the number of spectral lines when performing the cross correlation. The resulting cross-correlation functions are then normalized by a stellar template to remove the stellar signal. Carefully selected sections of the resulting normalized CCFs are stacked to increase the planetary signal further. The recovered signal allows probing several of the planetary properties, including its real mass and albedo. Results. We detect evidence for the reflected signal from planet 51 Peg b at a significance of 3σ noise . The detection of the signal permits us to infer a real mass of 0.46 +0.06 −0.01 M Jup (assuming a stellar mass of 1.04 M Sun ) for the planet and an orbital inclination of 80 +10 −19 degrees. The analysis of the data also allows us to infer a tentative value for the (radius-dependent) geometric albedo of the planet. The results suggest that 51Peg b may be an inflated hot Jupiter with a high albedo (e.g., an albedo of 0.5 yields a radius of 1.9 ± 0.3 R Jup for a signal amplitude of 6.0 ± 0.4 × 10 −5 ). Conclusions. We confirm that the method we perfected can be used to retrieve an exoplanet's reflected signal, even with current observing facilities. The advent of next generation of instruments (e.g. VLT-ESO/ESPRESSO) and observing facilities (e.g. a new generation of ELT telescopes) will yield new opportunities for this type of technique to probe deeper into exoplanets and their atmospheres.

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“…The data were reduced using the default settings and were then fed to the CCF calculation recipe, used with a weighted G2 mask (Pepe et al 2002).…”

Section: Data Reductionmentioning

confidence: 99%

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

Martins

Santos

Figueira

et al. 2015

A&A

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132

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“…The orders are then merged and rebinned after correction of the blaze function, yielding a one-dimensional spectrum (S1D). The E2DS spectra are cross-correlated with numerical masks corresponding to different spectral types (F0, G2, K0, K5, M4), and the resulting cross-correlation functions (CCFs) are fitted by Gaussians to get the radial velocities (Baranne et al 1996;Pepe et al 2002).…”

Section: The Sophie Spectrographmentioning

confidence: 99%

“…To benefit from experience acquired on HARPS (Pepe et al 2002) and take the limitations of the ELODIE spectrograph into account (Baranne et al 1996), SOPHIE was designed to obtain precise radial velocities with much higher throughput than its Based on observations made with SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS/OAMP), France (program 07A.PNP.CONS). Table 2 is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/505/853 predecessor and to be operated as a northern counterpart of HARPS.…”

Section: Introductionmentioning

confidence: 99%

The SOPHIE search for northern extrasolar planets

Bouchy

Hébrard²,

Udry

et al. 2009

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We report on the discovery of a substellar companion or a massive Jupiter orbiting the G5V star HD 16760 using the spectrograph SOPHIE installed on the OHP 1.93-m telescope. Characteristics and performances of the spectrograph are presented, as well as the SOPHIE exoplanet consortium program. With a minimum mass of 14.3 M Jup , an orbital period of 465 days and an eccentricity of 0.067, HD 16760b seems to be located just at the end of the mass distribution of giant planets, close to the planet/brown-dwarf transition. Its quite circular orbit supports a formation in a gaseous protoplanetary disk.

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“…Following the techniques described by Baranne et al (1996) and Pepe et al (2002), the radial velocities were measured from a weighted cross-correlation of the spectra with a numerical mask. We used a standard F0 mask that includes more than 3300 lines; cross-correlations with G2 and K5 masks gave similar results.…”

Section: Radial Velocity Observationsmentioning

confidence: 99%

Transiting exoplanets from the CoRoT space mission

Fridlund¹,

Hébrard

Alonso

et al. 2010

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The CoRoT satellite exoplanetary team announces its sixth transiting planet in this paper. We describe and discuss the satellite observations as well as the complementary ground-based observations -photometric and spectroscopic -carried out to assess the planetary nature of the object and determine its specific physical parameters. The discovery reported here is a "hot Jupiter" planet in an 8.9d orbit, 18 stellar radii, or 0.08 AU, away from its primary star, which is a solar-type star (F9V) with an estimated age of 3.0 Gyr. The planet mass is close to 3 times that of Jupiter. The star has a metallicity of 0.2 dex lower than the Sun, and a relatively high 7 Li abundance. While the light curve indicates a much higher level of activity than, e.g., the Sun, there is no sign of activity spectroscopically in e.g., the [Ca ii] H&K lines.

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The CORALIE survey for southern extra-solar planets VII

Cited by 552 publications

References 20 publications

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

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

The SOPHIE search for northern extrasolar planets

Transiting exoplanets from the CoRoT space mission

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