An HST optical-to-near-IR transmission spectrum of the hot Jupiter WASP-19b: detection of atmospheric water and likely absence of TiO

By C. Huitson, D. Sing, F. Pont, Jon Fortney, Adam Burrows, P. Wilson, Gilda E. Ballester, N. Nikolov, Neale P. Gibson, D. Deming and 7 more. 2013

147 citations recorded by the source corpus.

We measure the transmission spectrum of WASP-19b from three transits using low-resolution optical spectroscopy from the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS). The STIS spectra cover a wavelength range of 0.29-1.03 µm, with resolving power R = 500. The optical data are combined with archival near-infrared data from the HST Wide Field Camera 3 (WFC3) G141 grism, covering the wavelength range from 1.087 to 1.687 µm, with resolving power R = 130. We reach S/N levels between 3,000 and 11,000 in 0.1 µm bins when measuring the transmission spectra from 0.53-1.687 µm. WASP-19 is known to be a very active star, with the optical stellar flux varying by a few per cent over time. We correct the transit light curves for the effects of stellar activity using ground-based activity monitoring with the Cerro Tololo Inter-American Observatory (CTIO). While we were not able to construct a transmission spectrum using the blue optical data because of the presence of large occulted star spots, we were able to use the spot crossings to help constrain the mean stellar spot temperature. To search for predicted features in the hot-Jupiter atmosphere, in addition to the transmission spectrum we also define spectral indices for differential radius (�RP/R⋆) measurements to specifically search for the presence of TiO and alkali line features. Our measurements rule out TiO features predicted for a planet of WASP-19b’s equilibrium temperature (2050 K) in the transmission spectrum at the 2.7-2.9 σ confidence level, depending on atmospheric model formalism. The WFC3 transmission spectrum shows strong absorption features due to the presence of H2O, which is detected at the 4 σ confidence level between 1.1 and 1.4 µm. The transmission spectra results indicate that WASP-19b is a planet with no or low levels of TiO and without a high C/O ratio. The lack of observable TiO features are possibly due to rainout, breakdown from stellar activity or the presence of other absorbers in the optical.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b5b92a24c29cb82bf611e373986d28fe075f9fdd

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In Astronomy and Astrophysics

1. N. Madhusudhan
2. Jon Fortney
3. A. Showman
4. D. Sing
5. M. Line
6. D. Deming
7. J. D'esert
8. V. Parmentier

In Instrumentation

1. Jon Fortney
2. N. Madhusudhan
3. A. Showman
4. D. Sing
5. M. Line
6. V. Parmentier
7. J. D'esert
8. H. Knutson

Citations in the corpus

• DETECTION OF H2O AND EVIDENCE FOR TiO/VO IN AN ULTRA-HOT EXOPLANET ATMOSPHERE (2016, background): “Of these, TiO/VO absorption has been ruled out for WASP-12b (Teq ∼ 2600 K; Sing et al. 2013) and WASP-19b (Teq ∼ 2100 K; Huitson et al. 2013), while evidence for TiO emission has been reported for WASP-33b (Teq ∼ 2700 K; Haynes et al. 2015).”
• Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects (2019, unknown): “pheres with dierent observing techniques. Transmission Spectra (Primary Eclipse) Chemical Species Planet (References) H 2O HD 189733b (178), HD 209458b (63), WASP-12b (133), WASP-17b (171), WASP-19b (112), WASP-39b (276), WASP-43b (132), WASP-52b (266), WASP-63b (123), WASP-69b (266), WASP-76b (266)”
• HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and Rayleigh scattering (2014, methodology): “Similar to our previous STIS analysis (Sing et al. 2013; Huitson et al. 2013; Nikolov et al. 2014b), we intended to discard the entire first orbit to minimise the effect of the breathing trend, but found for two of the three HST visits, a few of the exposures taken toward the end of the first orbit…”
• NO THERMAL INVERSION AND A SOLAR WATER ABUNDANCE FOR THE HOT JUPITER HD 209458B FROM HST/WFC3 SPECTROSCOPY (2016, background): “…of transiting exoplanets are rapidly transforming our knowledge of planetary atmospheres (Berta et al. 2012; Swain et al. 2012; Deming et al. 2013; Huitson et al. 2013; Kreidberg et al. 2014ab,15; Stevenson et al. 2014c; McCullough et al. 2014; Knutson et al. 2014; Fraine et al. 2014; Evans et…”
• WATER VAPOR IN THE SPECTRUM OF THE EXTRASOLAR PLANET HD 189733b. I. THE TRANSIT (2014, unknown): “Huitson et al. (2013) reported WFC3 observations of WASP-19b alone.”
• HST hot-Jupiter transmission spectral survey: evidence for aerosols and lack of TiO in the atmosphere of WASP-12b (2013, methodology): “3.0.1 STIS white-light curve fits Our overall analysis methods are similar to the HST analysis of Sing et al. (2011); Huitson et al. (2013) and Nikolov et al. (2013), which we also describe briefly here.”
• TRANSITIONS IN THE CLOUD COMPOSITION OF HOT JUPITERS (2016, background): “To date, the signature of TiO has been found in the two of the hottest exoplanets (Haynes et al. 2015; Evans et al. 2016) but no con- vincing evidence has been found for cooler ones (Désert et al. 2008; Huitson et al. 2013).”
• Observations of Transiting Exoplanets with the James Webb Space Telescope (JWST) (2014, background): “Starspots can greatly complicate the interpretation of transit data as a planet scans across a mottled stellar surface, changing the apparent depth of a transit from its true value or producing a flux change if the planet itself occults a starspot (Pont et al. 2013; Huitson et al. 2013).”
• Transmission spectral properties of clouds for hot Jupiter exoplanets (2014, background): “For instance, WFC3 spectra have detected large H2O features in HAT-P-1b and WASP-19b (Wakeford et al. 2013; Huitson et al. 2013) while these features can be muted or even absent for other planets like WASP-12b and WASP-31b (Sing et al. 2013; Sing et al. 2014).”
• Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b (2013, methodology): “Huitson et al. (2013) did not find evidence for this effect in the STIS G750L spectral data of WASP-19b, which is part of our survey.”
• A CONSISTENT RETRIEVAL ANALYSIS OF 10 HOT JUPITERS OBSERVED IN TRANSMISSION (2016, background): “Most notably, the ten hot Jupiters published in Sing et al. (2016) (for additional details of observations, see Pont et al. 2013; Line et al. 2013a; Huitson et al. 2013; Mandell et al. 2013; Sing et al. 2013, 2015; Wakeford et al. 2013; Nikolov et al. 2014, 2015; McCullough et al. 2014) represent a…”
• SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b (2015, background): “However, previous searches for TiO in other hot Jupiters using transmission spectroscopy have yielded either secure non-detections (Huitson et al. 2013; Sing et al. 2013) or inconclusive results (Désert et al. 2008).”
• The Transit Light Source Effect: False Spectral Features and Incorrect Densities for M-dwarf Transiting Planets (2017, background): “…in transit spectroscopy studies to constrain the contribution of unocculted photospheric heterogeneities to exoplanet transmission spectra (Pont et al. 2008; Sing et al. 2011; Huitson et al. 2013; Jordán et al. 2013; Pont et al. 2013; Fraine et al. 2014; Sing et al. 2016; Rackham et al. 2017).”
• Disentangling the Planet from the Star in Late-Type M Dwarfs: A Case Study of TRAPPIST-1g (2018, background): “The effect of stellar activity on transmission spectra is not a new phenomenon (Sing et al. 2011; Huitson et al. 2013; Cauley et al. 2017; Bruno et al. 2018; Cauley et al. 2018), where inhomogeneities in the stellar flux can cause noticeable effects on the measured transit depths.”
• The Hubble Space Telescope PanCET Program: Exospheric Mg ii and Fe ii in the Near-ultraviolet Transmission Spectrum of WASP-121b Using Jitter Decorrelation (2019, methodology): “This set of detrending parameters (hereafter called the ‘traditional model’) have been widely used to fit HST transit and eclipse light curves (e.g. Huitson et al. 2013; Wakeford et al. 2013; Nikolov et al. 2014; Demory et al. 2015; Sing et al. 2016; Lothringer et al. 2018), and even non-parametric…”