Proxima b: The Detection of the Earth-Type Planet Candidate Orbiting Our Closest Neighbor

Anglada-Escudé, G.; Tuomi, Mikko; Ribas, I.; Reiners, A.; Amado, P. J.; Anglada, Guillem

doi:10.1007/978-3-319-30648-3_31-1

Cited by 9 publications

(17 citation statements)

References 55 publications

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“…Using the RV solution of Anglada-Escudé et al (2016), Kipping et al (2017) derived the time of inferior conjunction T IC =2,456,678.78±0.56 HJD at an original epoch and the orbital period P=11.1856± 0.0013 days. We adopt the transit ephemeris in Kipping et al (2017) to predict the time of transit window in the BSST light curve.…”

Section: A Candidate Transit Eventmentioning

confidence: 99%

“…The mass and orbital period of the outer planet are constrained by the requirement that the Doppler reflex stellar RV should be <3 m s −1 to keep the planet undetectable in the high-precision observation of Anglada-Escudé et al (2016). The simulation results are presented in the left panel of Figure 7.…”

Section: Comparing With the Candidate Transit Events In Most Datamentioning

confidence: 99%

“…We still use the arbitrary orbital period of 22.58509days for the outer planet, and set its eccentricity to zero. The mass of the planet in the outer orbit should be less than 4.08 M ⊕ as the RV constraint (Anglada-Escudé et al 2016). We present the strengths of simulated TTVs in the left panel of Figure 8.…”

Section: Comparing With the Candidate Transit Events In Most Datamentioning

confidence: 99%

“…Analyzing the light curve observed using the Hubble Space Telescope (HST) over 40 hr, Demory et al (2015) detected a single transit-like event but it is unlikely associated with αCentauriBb. Recently, an Earth-mass planet around Proxima Centauri was discovered, using two highprecision RV instruments (Anglada-Escudé et al 2016 The geometric probability of transit for ProximaCentaurib is just about 1.5%. Nevertheless, efforts to detect its planetary transit are valuable, as such a discovery would be very important.…”

Section: Introductionmentioning

confidence: 99%

“…We started the photometric monitoring of ProximaCentauri in Antarctica right after the announcement of the discovery of ProximaCentaurib (Anglada-Escudé et al 2016). In August and September, Proxima Centauri is not observable at almost all observatories around the world, except for the sites in Antarctica.…”

Section: Introductionmentioning

confidence: 99%

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Searching for the Transit of the Earth-mass Exoplanet Proxima Centauri b in Antarctica: Preliminary Result

Liu

Jiang

Huang

et al. 2017

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ProximaCentauri is known as the closest star to the Sun. Recently, radial velocity (RV) observations revealed the existence of an Earth-mass planet around it. With an orbital period of ∼11 days, Proxima Centauri b is probably in the habitable zone of its host star. We undertook a photometric monitoring campaign to search for its transit, using the Bright Star Survey Telescope at the Zhongshan Station in Antarctica. A transit-like signal appearing on 2016 September 8 has been tentatively identified. Its midtime, T C =2,457,640.1990±0.0017 HJD, is consistent with the predicted ephemeris based on the RV orbit in a 1σ confidence interval. Time-correlated noise is pronounced in the light curve of ProximaCentauri, affecting the detection of transits. We develop a technique, in a Gaussian process framework, to gauge the statistical significance of a potential transit detection. The tentative transit signal reported here has a confidence level of 2.5σ. Further detection of its periodic signals is necessary to confirm the planetary transit of ProximaCentaurib. We plan to monitor ProximaCentauri in the next polar night at DomeA in Antarctica, taking advantage of continuous darkness. Kipping et al. reported two tentative transit-like signals of ProximaCentaurib observed by the Microvariability and Oscillation of Stars space telescope in 2014 and 2015. The midtransit time of our detection is 138minutes later than that predicted by their transit ephemeris. If all of the signals are real transits, the misalignment of the epochs plausibly suggests transit timing variations of ProximaCentaurib induced by an outer planet in this system.

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Section: A Candidate Transit Eventmentioning

confidence: 99%

Section: Comparing With the Candidate Transit Events In Most Datamentioning

confidence: 99%

Section: Comparing With the Candidate Transit Events In Most Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Searching for the Transit of the Earth-mass Exoplanet Proxima Centauri b in Antarctica: Preliminary Result

Liu

Jiang

Huang

et al. 2017

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Atmospheric characterization of terrestrial exoplanets in the mid-infrared: biosignatures, habitability, and diversity

et al. 2021

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Exoplanet science is one of the most thriving fields of modern astrophysics. A major goal is the atmospheric characterization of dozens of small, terrestrial exoplanets in order to search for signatures in their atmospheres that indicate biological activity, assess their ability to provide conditions for life as we know it, and investigate their expected atmospheric diversity. None of the currently adopted projects or missions, from ground or in space, can address these goals. In this White Paper, submitted to ESA in response to the Voyage 2050 Call, we argue that a large space-based mission designed to detect and investigate thermal emission spectra of terrestrial exoplanets in the mid-infrared wavelength range provides unique scientific potential to address these goals and surpasses the capabilities of other approaches. While NASA might be focusing on large missions that aim to detect terrestrial planets in reflected light, ESA has the opportunity to take leadership and spearhead the development of a large mid-infrared exoplanet mission within the scope of the “Voyage 2050” long-term plan establishing Europe at the forefront of exoplanet science for decades to come. Given the ambitious science goals of such a mission, additional international partners might be interested in participating and contributing to a roadmap that, in the long run, leads to a successful implementation. A new, dedicated development program funded by ESA to help reduce development and implementation cost and further push some of the required key technologies would be a first important step in this direction. Ultimately, a large mid-infrared exoplanet imaging mission will be needed to help answer one of humankind’s most fundamental questions: “How unique is our Earth?”

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Spectral and temporal variability of Earth observed in polarization

Sterzik

Bagnulo

Stam

et al. 2019

A&A

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Context. Earthshine, i.e. sun-light scattered by Earth and back-reflected from the lunar surface to Earth, allows observations of Earth's total flux and polarization with ground-based astronomical facilities on timescales from minutes to years. Like flux spectra, polarization spectra exhibit imprints of Earth's atmospheric and surface properties. Earth's polarization spectra may prove an important benchmark to constrain expected bio-signatures of Earth-like planets observed with future telescopes. Aims. We derive Earth's polarimetric phase curve from a statistically significant sample of Earthshine polarization spectra. The impact of changing Earth views on the variation of polarization spectra is investigated. Methods. We present a comprehensive set of spectropolarimetric observations of Earthshine as obtained by FORS2 at the VLT for phase angles from 50 • to 135 • (Sun-Earth-Moon angle), covering a spectral range from 4300Å to 9200Å. The degree of polarization in B, V, R, I passbands, the differential polarization vegetation index, and the equivalent width of the O 2 -A polarization band around 7600Å are determined with absolute errors around 0.1% in the degree of polarization. Earthshine polarization spectra are corrected for the effect of depolarization introduced by backscattering on the lunar surface, introducing systematic errors of the order of 1% in the degree of polarization. Results. Distinct viewing sceneries such as observing the Atlantic or Pacific side in Earthshine yield statistically different phase curves. The equivalent width defined for the O 2 -A band polarization is found to vary from -50Å to +20Å. A differential polarized vegetation index is introduced and reveals a larger vegetation signal for those viewing sceneries that contain larger fractions of vegetated surface areas. We corroborate the observed correlations with theoretical models from the literature, and conclude that the Vegetation Red Edge (VRE) is a robust and sensitive signature in polarization spectra of planet Earth. Conclusions. The overall behaviour of polarization of planet Earth in the continuum and in the O 2 -A band can be explained by existing models. Bio-signatures such as the O 2 -A band and the VRE are detectable in Earthshine polarization with a high degree of significance and sensitivity. An in-depth understanding of Earthshine's temporal and spectral variability requires improved models of Earth's biosphere, as a pre-requisite to interpret possible detections of polarised bio-signatures in Earth-like exoplanets in the future.

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Proxima b: The Detection of the Earth-Type Planet Candidate Orbiting Our Closest Neighbor

Cited by 9 publications

References 55 publications

Searching for the Transit of the Earth-mass Exoplanet Proxima Centauri b in Antarctica: Preliminary Result

Searching for the Transit of the Earth-mass Exoplanet Proxima Centauri b in Antarctica: Preliminary Result

Atmospheric characterization of terrestrial exoplanets in the mid-infrared: biosignatures, habitability, and diversity

Spectral and temporal variability of Earth observed in polarization

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