Infrared eclipses of the strongly irradiated planet WASP-33b, and oscillations of its host star

Drake Deming, Jonathan D. Fraine, Pedro V. Sada, Nikku Madhusudhan, Heather A. Knutson, Joseph Harrington, Jasmina Blecic, Sarah Nymeyer, Alexis M S Smith, Brian Jackson

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

We observe two secondary eclipses of the strongly irradiated transiting planet WASP-33b, in the Ksband at 2.15 μm, and one secondary eclipse each at 3.6 μm and 4.5 μm using Warm Spitzer. This planet orbits an A5V δ-Scuti star that is known to exhibit low-amplitude non-radial p-mode oscillations at about 0.1% semi-amplitude. We detect stellar oscillations in all of our infrared eclipse data, and also in one night of observations at J band (1.25 μm) out of eclipse. The oscillation amplitude, in all infrared bands except Ks, is about the same as in the optical. However, the stellar oscillations in Ksband (2.15 μm) have about twice the amplitude (0.2%) as seen in the optical, possibly because the Brackett-γ line falls in this bandpass. As regards the exoplanetary eclipse, we use our best-fit values for the eclipse depth, as well as the 0.9 μm eclipse observed by Smith et al., to explore possible states of the exoplanetary atmosphere, based on the method of Madhusudhan & Seager. On this basis we find two possible states for the atmospheric structure of WASP-33b. One possibility is a non-inverted temperature structure in spite of the strong irradiance, but this model requires an enhanced carbon abundance (C/O > 1). The alternative model has solar composition, but an inverted temperature structure. Spectroscopy of the planet at secondary eclipse, using a spectral resolution that can resolve the water vapor band structure, should be able to break the degeneracy between these very different possible states of the exoplanetary atmosphere. However, both of those model atmospheres absorb nearly all of the stellar irradiance with minimal longitudinal re-distribution of energy, strengthening the hypothesis of Cowan & Agol that the most strongly irradiated planets circulate energy poorly. Our measurement of the central phase of the eclipse yields ecos ω = 0.0003 ± 0.00013, which we regard as being consistent with a circular orbit. © 2012. The American Astronomical Society. All rights reserved..
Original languageEnglish
JournalAstrophysical Journal
DOIs
Publication statusPublished - 1 Aug 2012

Fingerprint

eclipses
planets
planet
oscillation
stars
oscillations
irradiance
atmosphere
stellar oscillations
atmospheric structure
spectral resolution
energy
atmospheres
water vapor
temperature
spectroscopy
carbon
circular orbits
night
orbits

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Deming, Drake ; Fraine, Jonathan D. ; Sada, Pedro V. ; Madhusudhan, Nikku ; Knutson, Heather A. ; Harrington, Joseph ; Blecic, Jasmina ; Nymeyer, Sarah ; Smith, Alexis M S ; Jackson, Brian. / Infrared eclipses of the strongly irradiated planet WASP-33b, and oscillations of its host star. In: Astrophysical Journal. 2012.
@article{50585e4982c84d5b98e0314b365542b7,
title = "Infrared eclipses of the strongly irradiated planet WASP-33b, and oscillations of its host star",
abstract = "We observe two secondary eclipses of the strongly irradiated transiting planet WASP-33b, in the Ksband at 2.15 μm, and one secondary eclipse each at 3.6 μm and 4.5 μm using Warm Spitzer. This planet orbits an A5V δ-Scuti star that is known to exhibit low-amplitude non-radial p-mode oscillations at about 0.1{\%} semi-amplitude. We detect stellar oscillations in all of our infrared eclipse data, and also in one night of observations at J band (1.25 μm) out of eclipse. The oscillation amplitude, in all infrared bands except Ks, is about the same as in the optical. However, the stellar oscillations in Ksband (2.15 μm) have about twice the amplitude (0.2{\%}) as seen in the optical, possibly because the Brackett-γ line falls in this bandpass. As regards the exoplanetary eclipse, we use our best-fit values for the eclipse depth, as well as the 0.9 μm eclipse observed by Smith et al., to explore possible states of the exoplanetary atmosphere, based on the method of Madhusudhan & Seager. On this basis we find two possible states for the atmospheric structure of WASP-33b. One possibility is a non-inverted temperature structure in spite of the strong irradiance, but this model requires an enhanced carbon abundance (C/O > 1). The alternative model has solar composition, but an inverted temperature structure. Spectroscopy of the planet at secondary eclipse, using a spectral resolution that can resolve the water vapor band structure, should be able to break the degeneracy between these very different possible states of the exoplanetary atmosphere. However, both of those model atmospheres absorb nearly all of the stellar irradiance with minimal longitudinal re-distribution of energy, strengthening the hypothesis of Cowan & Agol that the most strongly irradiated planets circulate energy poorly. Our measurement of the central phase of the eclipse yields ecos ω = 0.0003 ± 0.00013, which we regard as being consistent with a circular orbit. {\circledC} 2012. The American Astronomical Society. All rights reserved..",
author = "Drake Deming and Fraine, {Jonathan D.} and Sada, {Pedro V.} and Nikku Madhusudhan and Knutson, {Heather A.} and Joseph Harrington and Jasmina Blecic and Sarah Nymeyer and Smith, {Alexis M S} and Brian Jackson",
year = "2012",
month = "8",
day = "1",
doi = "10.1088/0004-637X/754/2/106",
language = "English",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",

}

Deming, D, Fraine, JD, Sada, PV, Madhusudhan, N, Knutson, HA, Harrington, J, Blecic, J, Nymeyer, S, Smith, AMS & Jackson, B 2012, 'Infrared eclipses of the strongly irradiated planet WASP-33b, and oscillations of its host star', Astrophysical Journal. https://doi.org/10.1088/0004-637X/754/2/106

Infrared eclipses of the strongly irradiated planet WASP-33b, and oscillations of its host star. / Deming, Drake; Fraine, Jonathan D.; Sada, Pedro V.; Madhusudhan, Nikku; Knutson, Heather A.; Harrington, Joseph; Blecic, Jasmina; Nymeyer, Sarah; Smith, Alexis M S; Jackson, Brian.

In: Astrophysical Journal, 01.08.2012.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Infrared eclipses of the strongly irradiated planet WASP-33b, and oscillations of its host star

AU - Deming, Drake

AU - Fraine, Jonathan D.

AU - Sada, Pedro V.

AU - Madhusudhan, Nikku

AU - Knutson, Heather A.

AU - Harrington, Joseph

AU - Blecic, Jasmina

AU - Nymeyer, Sarah

AU - Smith, Alexis M S

AU - Jackson, Brian

PY - 2012/8/1

Y1 - 2012/8/1

N2 - We observe two secondary eclipses of the strongly irradiated transiting planet WASP-33b, in the Ksband at 2.15 μm, and one secondary eclipse each at 3.6 μm and 4.5 μm using Warm Spitzer. This planet orbits an A5V δ-Scuti star that is known to exhibit low-amplitude non-radial p-mode oscillations at about 0.1% semi-amplitude. We detect stellar oscillations in all of our infrared eclipse data, and also in one night of observations at J band (1.25 μm) out of eclipse. The oscillation amplitude, in all infrared bands except Ks, is about the same as in the optical. However, the stellar oscillations in Ksband (2.15 μm) have about twice the amplitude (0.2%) as seen in the optical, possibly because the Brackett-γ line falls in this bandpass. As regards the exoplanetary eclipse, we use our best-fit values for the eclipse depth, as well as the 0.9 μm eclipse observed by Smith et al., to explore possible states of the exoplanetary atmosphere, based on the method of Madhusudhan & Seager. On this basis we find two possible states for the atmospheric structure of WASP-33b. One possibility is a non-inverted temperature structure in spite of the strong irradiance, but this model requires an enhanced carbon abundance (C/O > 1). The alternative model has solar composition, but an inverted temperature structure. Spectroscopy of the planet at secondary eclipse, using a spectral resolution that can resolve the water vapor band structure, should be able to break the degeneracy between these very different possible states of the exoplanetary atmosphere. However, both of those model atmospheres absorb nearly all of the stellar irradiance with minimal longitudinal re-distribution of energy, strengthening the hypothesis of Cowan & Agol that the most strongly irradiated planets circulate energy poorly. Our measurement of the central phase of the eclipse yields ecos ω = 0.0003 ± 0.00013, which we regard as being consistent with a circular orbit. © 2012. The American Astronomical Society. All rights reserved..

AB - We observe two secondary eclipses of the strongly irradiated transiting planet WASP-33b, in the Ksband at 2.15 μm, and one secondary eclipse each at 3.6 μm and 4.5 μm using Warm Spitzer. This planet orbits an A5V δ-Scuti star that is known to exhibit low-amplitude non-radial p-mode oscillations at about 0.1% semi-amplitude. We detect stellar oscillations in all of our infrared eclipse data, and also in one night of observations at J band (1.25 μm) out of eclipse. The oscillation amplitude, in all infrared bands except Ks, is about the same as in the optical. However, the stellar oscillations in Ksband (2.15 μm) have about twice the amplitude (0.2%) as seen in the optical, possibly because the Brackett-γ line falls in this bandpass. As regards the exoplanetary eclipse, we use our best-fit values for the eclipse depth, as well as the 0.9 μm eclipse observed by Smith et al., to explore possible states of the exoplanetary atmosphere, based on the method of Madhusudhan & Seager. On this basis we find two possible states for the atmospheric structure of WASP-33b. One possibility is a non-inverted temperature structure in spite of the strong irradiance, but this model requires an enhanced carbon abundance (C/O > 1). The alternative model has solar composition, but an inverted temperature structure. Spectroscopy of the planet at secondary eclipse, using a spectral resolution that can resolve the water vapor band structure, should be able to break the degeneracy between these very different possible states of the exoplanetary atmosphere. However, both of those model atmospheres absorb nearly all of the stellar irradiance with minimal longitudinal re-distribution of energy, strengthening the hypothesis of Cowan & Agol that the most strongly irradiated planets circulate energy poorly. Our measurement of the central phase of the eclipse yields ecos ω = 0.0003 ± 0.00013, which we regard as being consistent with a circular orbit. © 2012. The American Astronomical Society. All rights reserved..

U2 - 10.1088/0004-637X/754/2/106

DO - 10.1088/0004-637X/754/2/106

M3 - Article

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

ER -