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

C. M. Huitson; D. K. Sing; F. Pont; J. J. Fortney; Adam S. Burrows; P. A. Wilson; G. E. Ballester; N. Nikolov; N. P. Gibson; D. Deming; S. Aigrain; T. M. Evans; G. W. Henry; A. Lecavelier des Etangs; A. P. Showman; A. Vidal-Madjar; K. Zahnle

doi:10.1093/mnras/stt1243

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

C. M. Huitson, D. K. Sing, F. Pont, J. J. Fortney, Adam S. Burrows, P. A. Wilson, G. E. Ballester, N. Nikolov, N. P. Gibson, D. Deming, S. Aigrain, T. M. Evans, G. W. Henry, A. Lecavelier des Etangs, A. P. Showman, A. Vidal-Madjar, K. Zahnle

Research output: Contribution to journal › Article › peer-review

144 Scopus citations

Abstract

We measure the transmission spectrum ofWASP-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 signal-to-noise levels between 3000 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. While we were not able to construct a transmission spectrum using the blue optical data because of the presence of large occulted starspots, 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 (δR_P/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 2.7-2.9σ 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 4σ 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.

Original language	English (US)
Pages (from-to)	3252-3274
Number of pages	23
Journal	Monthly Notices of the Royal Astronomical Society
Volume	434
Issue number	4
DOIs	https://doi.org/10.1093/mnras/stt1243
State	Published - Oct 2013

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

Planetary systems
Planets and satellites: atmospheres
Planets and satellites: individual: WASP-19b
Stars: individual: WASP-19
Techniques: spectroscopic

Access to Document

10.1093/mnras/stt1243

Cite this

Huitson, C. M., Sing, D. K., Pont, F., Fortney, J. J., Burrows, A. S., Wilson, P. A., Ballester, G. E., Nikolov, N., Gibson, N. P., Deming, D., Aigrain, S., Evans, T. M., Henry, G. W., des Etangs, A. L., Showman, A. P., Vidal-Madjar, A., & Zahnle, K. (2013). An HST optical-to-near-IR transmission spectrum of the hot Jupiter WASP-19b: Detection of atmospheric water and likely absence of TiO. Monthly Notices of the Royal Astronomical Society, 434(4), 3252-3274. https://doi.org/10.1093/mnras/stt1243

@article{a1251c4d5d3b4cebacbc91ab98bf8ccb,

title = "An HST optical-to-near-IR transmission spectrum of the hot Jupiter WASP-19b: Detection of atmospheric water and likely absence of TiO",

abstract = "We measure the transmission spectrum ofWASP-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 signal-to-noise levels between 3000 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. While we were not able to construct a transmission spectrum using the blue optical data because of the presence of large occulted starspots, 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 (δRP/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 2.7-2.9σ 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 4σ 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.",

keywords = "Planetary systems, Planets and satellites: atmospheres, Planets and satellites: individual: WASP-19b, Stars: individual: WASP-19, Techniques: spectroscopic",

author = "Huitson, {C. M.} and Sing, {D. K.} and F. Pont and Fortney, {J. J.} and Burrows, {Adam S.} and Wilson, {P. A.} and Ballester, {G. E.} and N. Nikolov and Gibson, {N. P.} and D. Deming and S. Aigrain and Evans, {T. M.} and Henry, {G. W.} and {des Etangs}, {A. Lecavelier} and Showman, {A. P.} and A. Vidal-Madjar and K. Zahnle",

year = "2013",

month = oct,

doi = "10.1093/mnras/stt1243",

language = "English (US)",

volume = "434",

pages = "3252--3274",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "4",

}

Huitson, CM, Sing, DK, Pont, F, Fortney, JJ, Burrows, AS, Wilson, PA, Ballester, GE, Nikolov, N, Gibson, NP, Deming, D, Aigrain, S, Evans, TM, Henry, GW, des Etangs, AL, Showman, AP, Vidal-Madjar, A & Zahnle, K 2013, 'An HST optical-to-near-IR transmission spectrum of the hot Jupiter WASP-19b: Detection of atmospheric water and likely absence of TiO', Monthly Notices of the Royal Astronomical Society, vol. 434, no. 4, pp. 3252-3274. https://doi.org/10.1093/mnras/stt1243

TY - JOUR

T1 - An HST optical-to-near-IR transmission spectrum of the hot Jupiter WASP-19b

T2 - Detection of atmospheric water and likely absence of TiO

AU - Huitson, C. M.

AU - Sing, D. K.

AU - Pont, F.

AU - Fortney, J. J.

AU - Burrows, Adam S.

AU - Wilson, P. A.

AU - Ballester, G. E.

AU - Nikolov, N.

AU - Gibson, N. P.

AU - Deming, D.

AU - Aigrain, S.

AU - Evans, T. M.

AU - Henry, G. W.

AU - des Etangs, A. Lecavelier

AU - Showman, A. P.

AU - Vidal-Madjar, A.

AU - Zahnle, K.

PY - 2013/10

Y1 - 2013/10

N2 - We measure the transmission spectrum ofWASP-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 signal-to-noise levels between 3000 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. While we were not able to construct a transmission spectrum using the blue optical data because of the presence of large occulted starspots, 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 (δRP/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 2.7-2.9σ 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 4σ 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.

AB - We measure the transmission spectrum ofWASP-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 signal-to-noise levels between 3000 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. While we were not able to construct a transmission spectrum using the blue optical data because of the presence of large occulted starspots, 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 (δRP/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 2.7-2.9σ 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 4σ 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.

KW - Planetary systems

KW - Planets and satellites: atmospheres

KW - Planets and satellites: individual: WASP-19b

KW - Stars: individual: WASP-19

KW - Techniques: spectroscopic

UR - http://www.scopus.com/inward/record.url?scp=84885113537&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84885113537&partnerID=8YFLogxK

U2 - 10.1093/mnras/stt1243

DO - 10.1093/mnras/stt1243

M3 - Article

AN - SCOPUS:84885113537

SN - 0035-8711

VL - 434

SP - 3252

EP - 3274

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 4

ER -

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

Abstract

All Science Journal Classification (ASJC) codes

Keywords

Access to Document

Other files and links

Fingerprint

Cite this