METALS IN THE EXOSPHERE OF THE HIGHLY IRRADIATED PLANET WASP-12b

被引：267

作者：

Fossati, L. ^{[1
]}

Haswell, C. A. ^{[1
]}

Froning, C. S. ^{[2
,14
]}

Hebb, L. ^{[3
]}

Holmes, S. ^{[1
]}

Kolb, U. ^{[1
]}

Helling, Ch. ^{[4
]}

Carter, A. ^{[1
]}

Wheatley, P. ^{[5
]}

Cameron, A. C. ^{[4
]}

Loeillet, B. ^{[6
,7
]}

Pollacco, D. ^{[8
]}

Street, R. ^{[9
]}

Stempels, H. C. ^{[4
,15
]}

Simpson, E. ^{[8
]}

Udry, S. ^{[10
]}

Joshi, Y. C. ^{[8
]}

West, R. G. ^{[11
]}

Skillen, I. ^{[12
]}

Wilson, D. ^{[13
,16
]}

机构：

[1] Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England

[2] Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA

[3] Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA

[4] Univ St Andrews, Sch Phys & Astron, SUPA, St Andrews KY16 9SS, Fife, Scotland

[5] Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England

[6] Lab Astrophys Marseille, F-13376 Marseille 12, France

[7] Univ Aix Marseille 1, CNRS, UMR 6110, F-13331 Marseille 3, France

[8] Queens Univ Belfast, Sch Math & Phys, Astrophys Res Ctr, Belfast BT7 1NN, Antrim, North Ireland

[9] Las Cumbres Observ, Santa Barbara, CA 93117 USA

[10] Univ Geneva, Observ Geneve, CH-1290 Sauverny, Switzerland

[11] Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England

[12] Isaac Newton Grp Telescopes, Tenerife, Spain

[13] Univ Keele, Astrophys Grp, Keele ST5 5BG, Staffs, England

[14] Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA

[15] Dept Phys & Astron, SE-75120 Uppsala, Sweden

[16] Univ Kent, Ctr Astrophys & Planetary Sci, Canterbury CT2 7NH, Kent, England

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2010年 / 714卷 / 02期

关键词：

stars:; individual; (WASP-12); RESONANCE-ABSORPTION LINES; ENERGETIC NEUTRAL ATOMS; EXTRASOLAR PLANET; EXOPLANET HD-209458B; WAVELENGTHS LONGWARD; ATMOSPHERE; HYDROGEN;

D O I：

10.1088/2041-8205/714/2/L222

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

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 angstrom), NUVB (2655-2696 angstrom), and NUVC (2770-2811 angstrom). 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 2.5 sigma level. We detect extra absorption in the Mg II lambda lambda 2800 resonance line cores at the 2.8 sigma 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.

引用

页码：L222 / L227

页数：6

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