A super-Earth transiting a nearby low-mass star

Charbonneau, David; Berta, Zachory K.; Irwin, Jonathan; Burke, Christopher J.; Nutzman, P.; Buchhave, Lars A.; Lovis, C.; Bonfils, X.; Latham, David W.; Udry, S.; Murray-Clay, Ruth; Holman, Matthew J.; Falco, E.; Winn, Joshua N.; Queloz, D.; Pepe, F.; Mayor, M.; Delfosse, X.; Forveille, T.

doi:10.1038/nature08679

Cited by 768 publications

(830 citation statements)

References 27 publications

(20 reference statements)

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“…With an age of 3-10Gyr (Charbonneau et al 2009), the photometric variability of GJ1214 may be faculae-dominated as well. Our data are most consistent with unocculted faculae in the photosphere of GJ1214 producing the observed offset in the optical transmission spectrum of GJ1214b.…”

Section: Physical Interpretation Of Cpat Modelmentioning

confidence: 99%

“…We use the CPAT-temperature model to investigate how cool, unocculted starspots reported in the literature could affect the transmission spectrum. Long-term monitoring shows that GJ1214 demonstrates a 1% peak-topeak variability in the MEarth (Nutzman & Charbonneau 2008) bandpass ( l < < 715 nm 1000 nm) on a timescale that is an integer multiple of 53 days (Berta et al 2011), which has been attributed to rotational modulation of cool starspots (Charbonneau et al 2009;Berta et al 2011;Fraine et al 2013). We calculate the spot-covering fraction implied by the variability using PHOENIX model spectra with = g log 5.0 and…”

Section: Tablementioning

confidence: 99%

“…GJ1214b (Charbonneau et al 2009) provides an excellent opportunity to study a low-mass planet with transmission spectroscopy. Orbiting an M4.5 dwarf only 14.55 parsecs away (Anglada-Escudé et al 2013), the large transit depth of the planet and apparent brightness of its host star make it very suitable for in-depth study through transmission spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

Rackham

Espinoza

Apai

et al. 2017

ApJ

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GJ1214b is the most studied sub-Neptune exoplanet to date. Recent measurements have shown its near-infrared transmission spectrum to be flat, pointing to a high-altitude opacity source in the exoplanetʼs atmosphere, either equilibrium condensate clouds or photochemical hazes. Many photometric observations have been reported in the optical by different groups, though simultaneous measurements spanning the entire optical regime are lacking. We present an optical transmission spectrum (4500-9260Å) of GJ1214b in 14 bins, measured with Magellan/IMACS repeatedly over three transits. We measure a mean planet-to-star radius ratio of ( ) in the spectral bins. The optical transit depths are shallower on average than observed in the near-infrared. We present a model for jointly incorporating the effects of a composite photosphere and atmospheric transmission through the exoplanetʼs limb (the CPAT model), and use it to examine the cases of absorber and temperature heterogeneities in the stellar photosphere. We find the optical and near-infrared measurements are best explained by the combination of (1) photochemical haze in the exoplanetary atmosphere with a mode particle size r=0.1μm and haze-forming efficiency = f 10% haze and (2) faculae in the unocculted stellar disk with a temperature contrast D = -+ T 354 46 46 K, assuming 3.2% surface coverage. The CPAT model can be used to assess potential contributions of heterogeneous stellar photospheres to observations of exoplanet transmission spectra, which will be important for searches for spectral features in the optical.

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Section: Physical Interpretation Of Cpat Modelmentioning

confidence: 99%

Section: Tablementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

Rackham

Espinoza

Apai

et al. 2017

ApJ

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“…Recent discoveries of Corot-7b (Leger et al 2009) and GL1214 (Charbonneau et al 2009) have increased interest in the questions of whether JWST will be able to characterize super earths. Deming et al (2009) have addressed this question in detail and find that depending upon the frequency of occurrence and the nature of their atmospheres, JWST can measure the temperature and identify molecular absorptions, such as water and CO 2 , of supe rearths orbiting lower main sequence stars.…”

Section: Spectroscopymentioning

confidence: 99%

The James Webb Space Telescope and its capabilities for exoplanet science

Clampin

2010

Proc. IAU

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Abstract. The James Webb Space Telescope is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 ?m to 28 ?m. JWSTs primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. JWSTs instrument complement offers numerous capabilities to study the formation and evolution of exoplanets via direct imaging, high contrast coronagraphic imaging and photometric and spectroscopic observations of transiting exoplanets.

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“…Furthermore, these objects are the most abundant in the solar neighborhood. Planets with masses between 1 and 10 M Earth , ''super-Earths,'' have indeed been detected in the last few years around low-mass stars, such as Gl 581 d and Gl 667C c by radial velocity (Udry et al, 2007;Mayor et al, 2009;Vogt et al, 2010;Bonfils et al, 2011;Forveille et al, 2011;AngladaEscudé et al, 2012;Delfosse et al, 2012) and GJ 1214 b by transit (Charbonneau et al, 2009;Sada et al, 2010;Carter et al, 2011;Kundurthy et al, 2011). Several observational campaigns designed specifically to detect planets around low-mass stars are now underway (Nutzman and Charbonneau, 2008;Boss et al, 2009;Zechmeister et al, 2009;Bean et al, 2010;Rodler et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

et al. 2013

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Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at highenough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets ''Tidal Venuses'' and the phenomenon a ''tidal greenhouse.'' Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with masses < 0.3 M Sun may be in danger of desiccation via tidal heating. We have applied these concepts to Gl 667C c, a *4.5 M Earth planet orbiting a 0.3 M Sun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories.

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A super-Earth transiting a nearby low-mass star

Cited by 768 publications

References 27 publications

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

The James Webb Space Telescope and its capabilities for exoplanet science

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

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