A Search for Additional Bodies in the GJ 1132 Planetary System from 21 Ground-based Transits and a 100-hr Spitzer Campaign

Dittmann, Jason; Irwin, Jonathan; Charbonneau, David; Berta-Thompson, Zachory K.; Newton, Elisabeth R.

doi:10.3847/1538-3881/aa855b

Cited by 47 publications

(66 citation statements)

References 60 publications

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“…In order to remove the intra-pixel sensitivity fluctuations that strongly affect Spitzer eclipse observations, we use the PLD method described in Deming et al (2015) (see Dittmann et al 2017, Kilpatrick et al 2017, Buhler et al 2016, Fischer et al 2016, and Wong et al 2016 for recent uses of PLD), with two updates. First, we use 12 pixels encompassing each stellar image as basis vectors in the decorrelations, rather than the 9 pixels used by Deming et al (2015).…”

Section: Data Analysis and Resultsmentioning

confidence: 99%

Spitzer secondary eclipses of Qatar-1b

Garhart

Deming

Mandell

et al. 2018

A&A

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Aims. Previous secondary eclipse observations of the hot Jupiter Qatar-1b in the Ks band suggest that it may have an unusually high day side temperature, indicative of minimal heat redistribution. There have also been indications that the orbit may be slightly eccentric, possibly forced by another planet in the system. We investigate the day side temperature and orbital eccentricity using secondary eclipse observations with Spitzer. Methods. We observed the secondary eclipse with Spitzer/IRAC in subarray mode, in both 3.6 and 4.5 µm wavelengths. We used pixel-level decorrelation to correct for Spitzer's intra-pixel sensitivity variations and thereby obtain accurate eclipse depths and central phases.Results. Our 3.6 µm eclipse depth is 0.149 ± 0.051% and the 4.5 µm depth is 0.273 ± 0.049%. Fitting a blackbody planet to our data and two recent Ks band eclipse depths indicates a brightness temperature of 1506 ± 71K. Comparison to model atmospheres for the planet indicates that its degree of longitudinal heat redistribution is intermediate between fully uniform and day-side only. The day side temperature of the planet is unlikely to be as high (1885K) as indicated by the ground-based eclipses in the Ks band, unless the planet's emergent spectrum deviates strongly from model atmosphere predictions. The average central phase for our Spitzer eclipses is 0.4984 ± 0.0017, yielding e cos ω = −0.0028 ± 0.0027. Our results are consistent with a circular orbit, and we constrain e cos ω much more strongly than has been possible with previous observations.

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Section: Data Analysis and Resultsmentioning

confidence: 99%

Spitzer secondary eclipses of Qatar-1b

Garhart

Deming

Mandell

et al. 2018

A&A

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“…Here, we briefly summarize the key steps and assumptions used in this work. We described above that the broad peak centered around ∼175 days in the LS periodogram of the RVs spans the stellar photometric rotation period of 125 days (Dittmann et al 2017a). Therefore, the stellar activity might be modulated at approximately the stellar rotation timescale.…”

Section: Joint Modeling Of Planets and Correlated "Noise"mentioning

confidence: 90%

“…(a) Upper limit, 95th percentile of the posterior PDF. M = 1.98842 × 10 30 kg, R = 6.95508 × 10 8 m, M ⊕ = 5.9736 × 10 24 kg, and R ⊕ = 6 378 137 m. (b) Assuming a planetary radius of 1.13 ± 0.056 R ⊕ (Dittmann et al 2017a).…”

Section: Joint Modeling Of Planets and Correlated "Noise"mentioning

confidence: 99%

Radial velocity follow-up of GJ1132 with HARPS

Bonfils

Almenara

Cloutier

et al. 2018

A&A

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The source GJ1132 is a nearby red dwarf known to host a transiting Earth-size planet. After its initial detection, we pursued an intense follow-up with the HARPS velocimeter. We now confirm the detection of GJ1132b with radial velocities alone. We refined its orbital parameters, and in particular, its mass (mb = 1.66 ± 0.23 M⊕), density (ρb = 6.3 ± 1.3 g cm−3), and eccentricity (eb < 0.22; 95%). We also detected at least one more planet in the system. GJ1132c is a super-Earth with period Pc = 8.93 ± 0.01 days and minimum mass mc sinic = 2.64 ± 0.44 M⊕. Receiving about 1.9 times more flux than Earth in our solar system, its equilibrium temperature is that of a temperate planet (Teq = 230−300 K for albedos A = 0.75 − 0.00), which places GJ1132c near the inner edge of the so-called habitable zone. Despite an a priori favorable orientation for the system, Spitzer observations reject most transit configurations, leaving a posterior probability <1% that GJ1132c transits. GJ1132(d) is a third signal with period Pd = 177 ± 5 days attributed to either a planet candidate with minimum mass md sin id = 8.4−2.5+1.7 M⊕ or stellar activity. Its Doppler signal is the most powerful in our HARPS time series but appears on a timescale where either the stellar rotation or a magnetic cycle are viable alternatives to the planet hypothesis. On the one hand, the period is different than that measured for the stellar rotation (~125 days), and a Bayesian statistical analysis we performed with a Markov chain Monte Carlo and Gaussian processes demonstrates that the signal is better described by a Keplerian function than by correlated noise. On the other hand, periodograms of spectral indices sensitive to stellar activity show power excess at similar periods to that of this third signal, and radial velocity shifts induced by stellar activity can also match a Keplerian function. We, therefore, prefer to leave the status of GJ1132(d) undecided.

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“…The optical transmission spectrum of GJ 1214b, which displays a significant decline towards shorter wavelengths and shallower transit depths than observed in the near-infrared (Kreidberg et al 2014a), has recently suggested a heterogeneous stellar photosphere dominated by hot faculae (Rackham et al 2017). Unocculted faculae have also been suggested to affect the transmission spectrum of GJ 1132b, which displays a significant decrease in transit depth at optical wavelengths (Dittmann et al 2017) and, like GJ 1214b, orbits a mid-M dwarf star (Berta-Thompson et al 2015). The suite of effects issued by active stars relates the importance for a framework capable of simultaneously dissecting properties of the planetary atmosphere and heterogeneous stellar photosphere from an observed spectrum.…”

Section: Introductionmentioning

confidence: 99%

Retrieval of planetary and stellar properties in transmission spectroscopy with Aura

Pinhas

Rackham

Madhusudhan

et al. 2018

Monthly Notices of the Royal Astronomical Society

124

163

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Transmission spectroscopy provides a powerful probe of the atmospheric properties of transiting exoplanets. To date, studies of exoplanets in transit have focused on inferring their atmospheric properties such as chemical compositions, cloud/haze properties, and temperature structures. However, surface inhomogeneities in the host stars of exoplanets in the form of cool spots and hot faculae can in principle imprint signatures on the observed planetary transit spectrum. Here we present Aura, a new retrieval paradigm for inferring both planetary and stellar properties from a transmission spectrum. We apply our retrieval framework to a sample of hot giant exoplanets to determine the significance of stellar heterogeneity and clouds/hazes in their spectra. The retrieval analyses distinguish four groups of planets. First, the spectra of WASP-6b and WASP-39b are best characterised by imprints of stellar heterogeneity and hazes and/or clouds. HD 209458b and HAT-P-12b comprise the second group for which there is weak evidence for stellar heterogeneity and a high significance of hazes and/or clouds. The third group constitutes HAT-P-1b and WASP-31b and shows weak evidence against stellar heterogeneity but weak to substantial indications of clouds/hazes. The fourth group -WASP-19b, WASP-17b, and WASP-12b -is fit best by molecular and alkali absorbers with H 2 scattering without evidence for stellar heterogeneity and weak to no evidence for clouds/hazes. Our retrieval methodology paves the way to simultaneous information on the star and planet from higher resolution spectra using future facilities such as the James Webb Space Telescope and large ground-based facilities.

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A Search for Additional Bodies in the GJ 1132 Planetary System from 21 Ground-based Transits and a 100-hr Spitzer Campaign

Cited by 47 publications

References 60 publications

Spitzer secondary eclipses of Qatar-1b

Spitzer secondary eclipses of Qatar-1b

Radial velocity follow-up of GJ1132 with HARPS

Retrieval of planetary and stellar properties in transmission spectroscopy with Aura

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