The centre-to-limb variations of solar Fraunhofer lines imprinted upon lunar eclipse spectra

被引：31
作者：
Yan, F. [1 ,2 ,3 ]
Fosbury, R. A. E. [3 ]
Petr-Gotzens, M. G. [3 ]
Zhao, G. [1 ]
Palle, E. [4 ,5 ]
机构：
[1] Chinese Acad Sci, Natl Astron Observ, Key Lab Opt Astron, Beijing 100012, Peoples R China
[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China
[3] European So Observ, D-85748 Garching, Germany
[4] Inst Astrofis Canarias, Tenerife 38205, Spain
[5] Univ La Laguna, Dept Astrofis, E-38206 Tenerife, Spain
来源：
ASTRONOMY & ASTROPHYSICS | 2015年 / 574卷
基金：
中国国家自然科学基金;
关键词：
planets and satellites: atmospheres; Earth; Moon; eclipses; stars: atmospheres; MESOSPHERIC SODIUM LAYER; EXOPLANET HD 209458B; TRANSMISSION SPECTRUM; EXTRASOLAR PLANET; ATMOSPHERE; EARTH; STAR; DAYSIDE; WATER; ABSORPTION;
D O I：
10.1051/0004-6361/201425220
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
The atmospheres of exoplanets are commonly studied by observing the transit of the planet passing in front of its parent star. The obscuration of part of the stellar disk during a transit will reveal aspects of its surface structure resulting from general centre-to-limb variations (CLVs). These become apparent when forming the ratio between the stellar light in and out of transit. These phenomena can be seen particularly clearly during the progress of a penumbral lunar eclipse, where the Earth transits the solar disk and masks different regions of the solar disk as the eclipse progresses. When inferring the properties of the planetary atmosphere, it is essential that this effect originating at the star is properly accounted for. Using the data observed from the 2014-April-15 lunar eclipse with the ESPaDOnS spectrograph mounted on the Canada France Hawaii Telescope (CFHT), we have obtained for the first time a time sequence of the penumbral spectra. These penumbral spectra enable us to study the centre-to-limb variations of solar Fraunhofer lines when the Earth is transiting Sun. The NaI and Call absorption features reported from previous lunar eclipse observations are demonstrated to be CLV features, which dominate the corresponding line profiles and mask possible planetary signal. Detecting atmospheric species in exoplanets via transit spectroscopy must account for the CLV effect.
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页数：9
相关论文
共 35 条
[1]   The Earth as an extrasolar transiting planet II. HARPS and UVES detection of water vapour, biogenic O2, and O3 [J].
Arnold, L. ;
Ehrenreich, D. ;
Vidal-Madjar, A. ;
Dumusque, X. ;
Nitschelm, C. ;
Querel, R. R. ;
Hedelt, P. ;
Berthier, J. ;
Lovis, C. ;
Moutou, C. ;
Ferlet, R. ;
Crooker, D. .
ASTRONOMY & ASTROPHYSICS, 2014, 564
[2]  
Athay R.G., 1972, Radiation Transport in Spectral Lines
[3]  
ATHAY RG, 1972, SOL PHYS, V24, P18, DOI 10.1007/BF00231078
[4]  
Brault J, 1972, Kitt Peak Solar Atlas
[5]   The signature of orbital motion from the dayside of the planet τ Bootis b [J].
Brogi, Matteo ;
Snellen, Ignas A. G. ;
de Kok, Remco J. ;
Albrecht, Simon ;
Birkby, Jayne ;
de Mooij, Ernst J. W. .
NATURE, 2012, 486 (7404) :502-504
[6]   Detection of an extrasolar planet atmosphere [J].
Charbonneau, D ;
Brown, TM ;
Noyes, RW ;
Gilliland, RL .
ASTROPHYSICAL JOURNAL, 2002, 568 (01) :377-384
[7]   Probing potassium in the atmosphere of HD 80606b with tunable filter transit spectrophotometry from the Gran Telescopio Canarias [J].
Colon, Knicole D. ;
Ford, Eric B. ;
Redfield, Seth ;
Fortney, Jonathan J. ;
Shabram, Megan ;
Deeg, Hans J. ;
Mahadevan, Suvrath .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2012, 419 (03) :2233-2250
[8]   PHOTOSPHERIC SPECTRUM LINE ASYMMETRIES AND WAVELENGTH SHIFTS [J].
DRAVINS, D .
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1982, 20 :61-89
[9]  
Dravins D., 2014, ARXIV14081402
[10]   A DETAILED SPECTROPOLARIMETRIC ANALYSIS OF THE PLANET-HOSTING STAR WASP-12 [J].
Fossati, L. ;
Bagnulo, S. ;
Elmasli, A. ;
Haswell, C. A. ;
Holmes, S. ;
Kochukhov, O. ;
Shkolnik, E. L. ;
Shulyak, D. V. ;
Bohlender, D. ;
Albayrak, B. ;
Froning, C. ;
Hebb, L. .
ASTROPHYSICAL JOURNAL, 2010, 720 (01) :872-886
1234