Atmosphere of WASP-12 b

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Atmosphere of WASP-12 b

Post by Sirius_Alpha on 15th December 2009, 12:30 am

Day-side z'-band emission and eccentricity of Wasp-12b
http://arxiv.org/abs/0912.2359

Abstract wrote:We report the detection of the eclipse of the very-hot Jupiter WASP-12b via z'-band time-series photometry obtained with the 3.5-meter ARC telescope at Apache Point Observatory. We measure a decrease in flux of 0.082+/-0.015% during the passage of the planet behind the star. That planetary flux is equally well reproduced by atmospheric models with and without extra absorbers, and a black-body model with Tz'~2660K, AB < 0.3, and Pn~0.5. The eclipse is centered at phase 0.5100+/-0.0022, consistent with an orbital eccentricity of |ecosw|=0.0156+/- 0.0035. Assuming the eccentricity is caused by other planets in the system and atmospheric opacities corresponding to solar metallicity abundance, the large radius of WASP-12b can be explained by tidal heating if Q'p < 3.82x10^7.


Last edited by Sirius_Alpha on 23rd September 2013, 9:25 pm; edited 1 time in total

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Metals In The Exosphere Of The Highly Irradiated Planet WASP-12b

Post by exoplanet on 16th April 2010, 11:41 am

The Cosmic Origins Spectrograph begins its magic ... Shocked

http://iopscience.iop.org/2041-8205/714/2/L222


We present near-UV transmission spectroscopy of the highly irradiated transiting exoplanet WASP-12b, obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope. The spectra cover three distinct wavelength ranges: NUVA (2539-2580 ), NUVB (2655-2696 ), and NUVC (2770-2811 ). Three independent methods all reveal enhanced transit depths attributable to absorption by resonance lines of metals in the exosphere of WASP-12b. Light curves of total counts in the NUVA and NUVC wavelength ranges show a detection at a 2.5σ level. We detect extra absorption in the Mg II λλ2800 resonance line cores at the 2.8σ level. The NUVA, NUVB, and NUVC light curves imply effective radii of 2.69 0.24 R J , 2.18 0.18 R J , and 2.66 0.22 R J respectively, suggesting the planet is surrounded by an absorbing cloud which overfills the Roche lobe. We detect enhanced transit depths at the wavelengths of resonance lines of neutral sodium, tin, and manganese, and at singly ionized ytterbium, scandium, manganese, aluminum, vanadium, and magnesium. We also find the statistically expected number of anomalous transit depths at wavelengths not associated with any known resonance line. Our data are limited by photon noise, but taken as a whole the results are strong evidence for an extended absorbing exosphere surrounding the planet. The NUVA data exhibit an early ingress, contrary to model expectations; we speculate this could be due to the presence of a disk of previously stripped material.

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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 16th April 2010, 12:10 pm

That is amazing. All those chemicals detected in the atmosphere.
I hope they do this for other transit planet hosts.

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Re: Atmosphere of WASP-12 b

Post by exoplanet on 16th April 2010, 7:36 pm

If they can get this level of detail (almost 3 sigma detections) for a 12 magnitude star, imagine the results for HD209458b or HD189733 !

I hope someone will remember/get the time to check for the alleged gas tail around 51 Peg b.

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Re: Atmosphere of WASP-12 b

Post by Stalker on 18th April 2010, 12:48 pm

I wonder what this planet looks like. it is beyond of the model of Sudarsky.
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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 18th April 2010, 3:28 pm

Sudarsky Class V is given for any planet over 1,400 K.

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Re: Atmosphere of WASP-12 b

Post by Stalker on 18th April 2010, 5:43 pm

But WASP-12 b have ~2500C, isn't it?
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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 18th April 2010, 6:40 pm

Yes. 2,500 C > 1,400 K, thus it falls under Sudarsky Class V.

Edit: Corrected for unit measurements.

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Re: Atmosphere of WASP-12 b

Post by Stalker on 19th April 2010, 1:10 am

Thanks.
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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 20th May 2010, 8:38 pm


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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 1st September 2010, 8:12 pm

More.

Near-infrared Thermal Emission from WASP-12b: detections of the secondary eclipse in Ks, H & J
http://arxiv.org/abs/1009.0071

Abstract wrote:We present Ks, H & J-band photometry of the very highly irradiated hot Jupiter WASP-12b using the Wide-field Infrared Camera on the Canada-France-Hawaii telescope. Our photometry brackets the secondary eclipse of WASP-12b in the Ks and H-bands, and in J-band starts in mid-eclipse and continues until well after the end of the eclipse. We detect its thermal emission in all three near-infrared bands. Our secondary eclipse depths are 0.309 +/- 0.013% in Ks-band (24-sigma), 0.176 +/- 0.020% in H-band (9-sigma) and 0.131 +/- 0.028% in J-band (4-sigma). All three secondary eclipses are best-fit with a consistent phase that is compatible with a circular orbit. By combining our secondary eclipse times with others published in the literature, as well as the radial velocity and transit timing data for this system, we show that there is no evidence that WASP-12b is precessing at a detectable rate, and show that its orbital eccentricity is likely zero. Our thermal emission measurements also allow us to constrain the characteristics of the planet's atmosphere; our Ks-band eclipse depth argues in favour of inefficient day to nightside redistribution of heat and a low Bond albedo for this very highly irradiated hot Jupiter. The J and H-band brightness temperatures are slightly cooler than the Ks-band brightness temperature, and thus hint at the possibility of a modest temperature inversion deep in the atmosphere of WASP-12b; the high pressure, deep atmospheric layers probed by our J and H-band observations are likely more homogenized than the higher altitude layer. Lastly, our best-fit Ks-band eclipse has a marginally longer duration than would otherwise be expected; this may be tentative evidence for material being tidally stripped from the planet - as was predicted for this system by Li & collaborators, and for which observational confirmation was recently arguably provided by Fossati & collaborators.

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Carbon-rich planet WASP-12b

Post by Lazarus on 8th December 2010, 8:22 pm

SpaceRef: NASA's Spitzer Reveals First Carbon-Rich Planet

Seems that WASP-12b has a carbon-to-oxygen ratio greater than 1. Maybe carbon-planets are quite common in the galaxy.
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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 8th December 2010, 9:09 pm

High C/O Ratio and Weak Thermal Inversion in the Very Hot Atmosphere of Exoplanet WASP-12b
http://arxiv.org/abs/1012.1603

The carbon-to-oxygen ratio (C/O) in a planet provides critical information about its primordial origins and subsequent evolution. A primordial C/O greater than 0.8 causes a carbide-dominated interior as opposed to a silicate-dominated composition as found on Earth, and the atmospheres can also differ from those in the Solar System. The solar C/O is 0.54. Here we report an analysis of dayside multi-wavelength photometry of the transiting hot-Jupiter WASP-12b that reveals C/O >= 1 in its atmosphere. The atmosphere is abundant in CO. It is depleted in water vapor and enhanced in methane by over two orders of magnitude each compared to a solar-abundance chemical-equilibrium model at the expected temperatures. We also find that the extremely irradiated atmosphere (T > 2,500 K) of WASP-12b lacks a prominent thermal inversion, or a stratosphere, and has very efficient day- night energy circulation. The absence of a strong thermal inversion is in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmospheres.

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Re: Atmosphere of WASP-12 b

Post by Lazarus on 9th December 2010, 2:08 pm

The news story on Nature News that also covers the implications of HR 8799e for planet formation theories points out that we don't actually have all that good an idea of what the carbon content of our own gas giants is:
But it is difficult to draw comparisons between WASP 12b and planets that we know, because of a lack of data on carbon/oxygen ratios for gas giants in our own Solar System.

...

Jupiter's carbon/oxygen ratio cannot be established by spectroscopic observations because most of its oxygen is trapped in water, which has condensed out of the atmosphere because Jupiter is so cold.
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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 28th December 2010, 7:29 pm

Bond et al. (2010) found that HD 108874 has a C/O ratio of 1.35, and mentioned that its planets may be carbon-rich, like WASP-12 b was was found to be. In October, it was reported that Spitzer data suggests HD 108874 has a debris disk.

Now in the paper that talks about WASP-12 b's C/O ratio, it points out that it's higher than the star's. They didn't seem sure how to explain this but they suggested carbon enrichment of planetesimals. Well, now we have a system that has a debris disk and is expected to produce carbon planets, HD 108874. Could we determine it's C/O ratio with what's available? What this shed any light on whether or not WASP-12 truly formed from a carbon-enriched disk (or oxygen depleted?)?

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Re: Atmosphere of WASP-12 b

Post by Lazarus on 3rd January 2011, 7:08 pm

Would be interesting to know what the elemental abundances in Beta Pictoris are...
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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 3rd January 2011, 7:29 pm

Oh yes I had forgotten about that. β Pic b would be a lot easier to investigate I'm sure.

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Re: Atmosphere of WASP-12 b

Post by Lazarus on 24th January 2011, 5:05 pm

Talking of β Pic, apparently it is even more carbon-rich than previously thought.
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Re: Atmosphere of WASP-12 b

Post by Lazarus on 28th June 2011, 3:00 pm

The star WASP-12 is reported to have sub-solar C/O ratio...

Carbon and Oxygen in Nearby Stars: Keys to Protoplanetary Disk Chemistry
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WASP-12b weirdness

Post by Lazarus on 6th December 2011, 4:16 pm

Thermal Phase Variations of WASP-12b: Defying Predictions
Some interesting implications (perhaps!) for the shape of the WASP-12b planet, and whether or not it is actually carbon-rich or not. Whatever the case it is an odd planet!
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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 23rd September 2013, 9:27 pm

HST hot Jupiter transmission spectral survey: evidence for aerosols and lack of TiO in the atmosphere of WASP-12b
http://arxiv.org/abs/1309.5261

We present HST optical transmission spectra of the transiting hot Jupiter WASP-12b, taken with the STIS instrument. From the transmission spectra, we are able to decisively rule out prominent absorption by TiO in the exoplanet's atmosphere. Strong pressure-broadened Na and K absorption signatures are also excluded, as are significant metal-hydride features. We compare our combined broadband spectrum to a wide variety of existing aerosol-free atmospheric models, though none are satisfactory fits. However, we do find that the full transmission spectrum can be described by models which include significant opacity from aerosols: including Rayleigh scattering, Mie scattering, tholin haze, and settling dust profiles. The transmission spectrum follows an effective extinction cross section with a power-law of index alpha, with the slope of the transmission spectrum constraining the quantity alphaT = -3528+/-660 K, where T is the atmospheric temperature. Rayleigh scattering (alpha=-4) is among the best fitting models, though requires low terminator temperatures near 900 K. Sub-micron size aerosol particles can provide equally good fits to the entire transmission spectrum for a wide range of temperatures, and we explore corundum as a plausible dust aerosol. The presence of atmospheric aerosols also helps to explain the modestly bright albedo implied by Spitzer observations, as well as the near black body nature of the emission spectrum. Ti-bearing condensates on the cooler night-side is the most natural explanation for the overall lack of TiO signatures in WASP-12b, indicating the day/night cold-trap is an important effect for very hot Jupiters. These finding indicate that aerosols can play a significant atmospheric role for the entire wide range of hot-Jupiter atmospheres, potentially affecting their overall spectrum and energy balance.(abridged)
Also, I've merged together some of the various WASP-12 atmosphere threads into a consolidated thread, similar to what we have for GJ 1214 b's atmosphere thread.

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Re: Atmosphere of WASP-12 b

Post by Sirius_Alpha on 15th September 2017, 3:14 am


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