Resumen
Context. Not only is gravitational microlensing a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event. Aims. In high-magnification events, the lens caustic may cross over the source disk, which allows determination of the angular size of the source and measurement of its limb darkening. Methods. When such extended-source effects appear close to maximum magnification, the resulting light curve differs from the characteristic Paczyński point-source curve. The exact shape of the light curve close to the peak depends on the limb darkening of the source. Dense photometric coverage permits measurement of the respective limb-darkening coefficients. Results. In the case of the microlensing event OGLE 2008-BLG-290, the K giant source star reached a peak magnification at about 100. Thirteen different telescopes have covered this event in eight different photometric bands. Subsequent light-curve analysis yielded measurements of linear limb-darkening coefficients of the source in six photometric bands. The best-measured coefficients lead to an estimate of the source effective temperature of about 4700$^{+100}-{-200}$ K. However, the photometric estimate from colour-magnitude diagrams favours a cooler temperature of 4200 ± 100 K. Conclusions. Because the limb-darkening measurements, at least in the CTIO/SMARTS2 Vs- and Is-bands, are among the most accurate obtained, the above disagreement needs to be understood. A solution is proposed, which may apply to previous events where such a discrepancy also appeared.
Idioma original | English |
---|---|
Número de artículo | A51 |
Publicación | Astronomy and Astrophysics |
Volumen | 518 |
N.º | 19 |
DOI | |
Estado | Published - 2 sep 2010 |
Huella dactilar
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
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OGLE 2008-BLG-290 : An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing. / Fouqué, P.; Heyrovský, D.; Dong, S.; Gould, A.; Udalski, A.; Albrow, M. D.; Batista, V.; Beaulieu, J. P.; Bennett, D. P.; Bond, I. A.; Bramich, D. M.; Calchi Novati, S.; Cassan, A.; Coutures, C.; Dieters, S.; Dominik, M.; Dominis Prester, D.; Greenhill, J.; Horne, K.; Jørgensen, U. G.; Kozłowski, S.; Kubas, D.; Lee, C. H.; Marquette, J. B.; Mathiasen, M.; Menzies, J.; Monard, L. A.G.; Nishiyama, S.; Papadakis, I.; Street, R.; Sumi, T.; Williams, A.; Yee, J. C.; Brillant, S.; Caldwell, J. A.R.; Cole, A.; Cook, K. H.; Donatowicz, J.; Kains, N.; Kane, S. R.; Martin, R.; Pollard, K. R.; Sahu, K. C.; Tsapras, Y.; Wambsganss, J.; Depoy, D. L.; Gaudi, B. S.; Han, C.; Lee, C. U.; Park, B. G.; Pogge, R. W.; Kubiak, M.; Szymański, M. K.; Pietrzyński, G.; Soszyński, I.; Szewczyk, O.; Ulaczyk, K.; Wyrzykowski, L.; Abe, F.; Fukui, A.; Furusawa, K.; Gilmore, A. C.; Hearnshaw, J. B.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Korpela, A. V.; Lin, W.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagaya, M.; Ohnishi, K.; Okumura, T.; Perrott, Y.; Rattenbury, N. J.; Saito, To; Sako, T.; Sato, S.; Skuljan, L.; Sullivan, D.; Sweatman, W.; Tristram, P. J.; Yock, P. C.M.; Allan, A.; Bode, M. F.; Burgdorf, M. J.; Clay, N.; Fraser, S. N.; Hawkins, E.; Kerins, E.; Lister, T. A.; Mottram, C. J.; Saunders, E. S.; Snodgrass, C.; Steele, I. A.; Wheatley, P. J.; Anguita, T.; Bozza, V.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Kjærgaard, P.; Liebig, C.; Mancini, L.; Masi, G.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Southworth, J.; Surdej, J.; Thöne, C. C.; Riffeser, A.; Seitz, S.; Bender, R.; Zub, M.
En: Astronomy and Astrophysics, Vol. 518, N.º 19, A51, 02.09.2010.Resultado de la investigación: Article
TY - JOUR
T1 - OGLE 2008-BLG-290
T2 - An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing
AU - Fouqué, P.
AU - Heyrovský, D.
AU - Dong, S.
AU - Gould, A.
AU - Udalski, A.
AU - Albrow, M. D.
AU - Batista, V.
AU - Beaulieu, J. P.
AU - Bennett, D. P.
AU - Bond, I. A.
AU - Bramich, D. M.
AU - Calchi Novati, S.
AU - Cassan, A.
AU - Coutures, C.
AU - Dieters, S.
AU - Dominik, M.
AU - Dominis Prester, D.
AU - Greenhill, J.
AU - Horne, K.
AU - Jørgensen, U. G.
AU - Kozłowski, S.
AU - Kubas, D.
AU - Lee, C. H.
AU - Marquette, J. B.
AU - Mathiasen, M.
AU - Menzies, J.
AU - Monard, L. A.G.
AU - Nishiyama, S.
AU - Papadakis, I.
AU - Street, R.
AU - Sumi, T.
AU - Williams, A.
AU - Yee, J. C.
AU - Brillant, S.
AU - Caldwell, J. A.R.
AU - Cole, A.
AU - Cook, K. H.
AU - Donatowicz, J.
AU - Kains, N.
AU - Kane, S. R.
AU - Martin, R.
AU - Pollard, K. R.
AU - Sahu, K. C.
AU - Tsapras, Y.
AU - Wambsganss, J.
AU - Depoy, D. L.
AU - Gaudi, B. S.
AU - Han, C.
AU - Lee, C. U.
AU - Park, B. G.
AU - Pogge, R. W.
AU - Kubiak, M.
AU - Szymański, M. K.
AU - Pietrzyński, G.
AU - Soszyński, I.
AU - Szewczyk, O.
AU - Ulaczyk, K.
AU - Wyrzykowski, L.
AU - Abe, F.
AU - Fukui, A.
AU - Furusawa, K.
AU - Gilmore, A. C.
AU - Hearnshaw, J. B.
AU - Itow, Y.
AU - Kamiya, K.
AU - Kilmartin, P. M.
AU - Korpela, A. V.
AU - Lin, W.
AU - Ling, C. H.
AU - Masuda, K.
AU - Matsubara, Y.
AU - Miyake, N.
AU - Muraki, Y.
AU - Nagaya, M.
AU - Ohnishi, K.
AU - Okumura, T.
AU - Perrott, Y.
AU - Rattenbury, N. J.
AU - Saito, To
AU - Sako, T.
AU - Sato, S.
AU - Skuljan, L.
AU - Sullivan, D.
AU - Sweatman, W.
AU - Tristram, P. J.
AU - Yock, P. C.M.
AU - Allan, A.
AU - Bode, M. F.
AU - Burgdorf, M. J.
AU - Clay, N.
AU - Fraser, S. N.
AU - Hawkins, E.
AU - Kerins, E.
AU - Lister, T. A.
AU - Mottram, C. J.
AU - Saunders, E. S.
AU - Snodgrass, C.
AU - Steele, I. A.
AU - Wheatley, P. J.
AU - Anguita, T.
AU - Bozza, V.
AU - Harpsøe, K.
AU - Hinse, T. C.
AU - Hundertmark, M.
AU - Kjærgaard, P.
AU - Liebig, C.
AU - Mancini, L.
AU - Masi, G.
AU - Rahvar, S.
AU - Ricci, D.
AU - Scarpetta, G.
AU - Southworth, J.
AU - Surdej, J.
AU - Thöne, C. C.
AU - Riffeser, A.
AU - Seitz, S.
AU - Bender, R.
AU - Zub, M.
PY - 2010/9/2
Y1 - 2010/9/2
N2 - Context. Not only is gravitational microlensing a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event. Aims. In high-magnification events, the lens caustic may cross over the source disk, which allows determination of the angular size of the source and measurement of its limb darkening. Methods. When such extended-source effects appear close to maximum magnification, the resulting light curve differs from the characteristic Paczyński point-source curve. The exact shape of the light curve close to the peak depends on the limb darkening of the source. Dense photometric coverage permits measurement of the respective limb-darkening coefficients. Results. In the case of the microlensing event OGLE 2008-BLG-290, the K giant source star reached a peak magnification at about 100. Thirteen different telescopes have covered this event in eight different photometric bands. Subsequent light-curve analysis yielded measurements of linear limb-darkening coefficients of the source in six photometric bands. The best-measured coefficients lead to an estimate of the source effective temperature of about 4700$^{+100}-{-200}$ K. However, the photometric estimate from colour-magnitude diagrams favours a cooler temperature of 4200 ± 100 K. Conclusions. Because the limb-darkening measurements, at least in the CTIO/SMARTS2 Vs- and Is-bands, are among the most accurate obtained, the above disagreement needs to be understood. A solution is proposed, which may apply to previous events where such a discrepancy also appeared.
AB - Context. Not only is gravitational microlensing a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event. Aims. In high-magnification events, the lens caustic may cross over the source disk, which allows determination of the angular size of the source and measurement of its limb darkening. Methods. When such extended-source effects appear close to maximum magnification, the resulting light curve differs from the characteristic Paczyński point-source curve. The exact shape of the light curve close to the peak depends on the limb darkening of the source. Dense photometric coverage permits measurement of the respective limb-darkening coefficients. Results. In the case of the microlensing event OGLE 2008-BLG-290, the K giant source star reached a peak magnification at about 100. Thirteen different telescopes have covered this event in eight different photometric bands. Subsequent light-curve analysis yielded measurements of linear limb-darkening coefficients of the source in six photometric bands. The best-measured coefficients lead to an estimate of the source effective temperature of about 4700$^{+100}-{-200}$ K. However, the photometric estimate from colour-magnitude diagrams favours a cooler temperature of 4200 ± 100 K. Conclusions. Because the limb-darkening measurements, at least in the CTIO/SMARTS2 Vs- and Is-bands, are among the most accurate obtained, the above disagreement needs to be understood. A solution is proposed, which may apply to previous events where such a discrepancy also appeared.
KW - Gravitational lensing: micro
KW - Stars: atmospheres
KW - Stars: individual: OGLE 2008-BLG-290
KW - Techniques: high angular resolution
UR - http://www.scopus.com/inward/record.url?scp=77956317225&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201014053
DO - 10.1051/0004-6361/201014053
M3 - Article
AN - SCOPUS:77956317225
VL - 518
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
IS - 19
M1 - A51
ER -