OGLE 2008-BLG-290: An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing

P. Fouqué; D. Heyrovský; S. Dong; A. Gould; A. Udalski; M. D. Albrow; V. Batista; J. P. Beaulieu; D. P. Bennett; I. A. Bond; D. M. Bramich; S. Calchi Novati; A. Cassan; C. Coutures; S. Dieters; M. Dominik; D. Dominis Prester; J. Greenhill; K. Horne; U. G. Jørgensen; S. Kozłowski; D. Kubas; C. H. Lee; J. B. Marquette; M. Mathiasen; J. Menzies; L. A.G. Monard; S. Nishiyama; I. Papadakis; R. Street; T. Sumi; A. Williams; J. C. Yee; S. Brillant; J. A.R. Caldwell; A. Cole; K. H. Cook; J. Donatowicz; N. Kains; S. R. Kane; R. Martin; K. R. Pollard; K. C. Sahu; Y. Tsapras; J. Wambsganss; D. L. Depoy; B. S. Gaudi; C. Han; C. U. Lee; B. G. Park; R. W. Pogge; M. Kubiak; M. K. Szymański; G. Pietrzyński; I. Soszyński; O. Szewczyk; K. Ulaczyk; L. Wyrzykowski; F. Abe; A. Fukui; K. Furusawa; A. C. Gilmore; J. B. Hearnshaw; Y. Itow; K. Kamiya; P. M. Kilmartin; A. V. Korpela; W. Lin; C. H. Ling; K. Masuda; Y. Matsubara; N. Miyake; Y. Muraki; M. Nagaya; K. Ohnishi; T. Okumura; Y. Perrott; N. J. Rattenbury; To Saito; T. Sako; S. Sato; L. Skuljan; D. Sullivan; W. Sweatman; P. J. Tristram; P. C.M. Yock; A. Allan; M. F. Bode; M. J. Burgdorf; N. Clay; S. N. Fraser; E. Hawkins; E. Kerins; T. A. Lister; C. J. Mottram; E. S. Saunders; C. Snodgrass; I. A. Steele; P. J. Wheatley; T. Anguita; V. Bozza; K. Harpsøe; T. C. Hinse; M. Hundertmark; P. Kjærgaard; C. Liebig; L. Mancini; G. Masi; S. Rahvar; D. Ricci; G. Scarpetta; J. Southworth; J. Surdej; C. C. Thöne; A. Riffeser; S. Seitz; R. Bender; M. Zub

doi:10.1051/0004-6361/201014053

OGLE 2008-BLG-290: An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing

P. Fouqué, D. Heyrovský, S. Dong, A. Gould, A. Udalski, M. D. Albrow, V. Batista, J. P. Beaulieu, D. P. Bennett, I. A. Bond, D. M. Bramich, S. Calchi Novati, A. Cassan, C. Coutures, S. Dieters, M. Dominik, D. Dominis Prester, J. Greenhill, K. Horne, U. G. JørgensenS. Kozłowski, D. Kubas, C. H. Lee, J. B. Marquette, M. Mathiasen, J. Menzies, L. A.G. Monard, S. Nishiyama, I. Papadakis, R. Street, T. Sumi, A. Williams, J. C. Yee, S. Brillant, J. A.R. Caldwell, A. Cole, K. H. Cook, J. Donatowicz, N. Kains, S. R. Kane, R. Martin, K. R. Pollard, K. C. Sahu, Y. Tsapras, J. Wambsganss, D. L. Depoy, B. S. Gaudi, C. Han, C. U. Lee, B. G. Park, R. W. Pogge, M. Kubiak, M. K. Szymański, G. Pietrzyński, I. Soszyński, O. Szewczyk, K. Ulaczyk, L. Wyrzykowski, F. Abe, A. Fukui, K. Furusawa, A. C. Gilmore, J. B. Hearnshaw, Y. Itow, K. Kamiya, P. M. Kilmartin, A. V. Korpela, W. Lin, C. H. Ling, K. Masuda, Y. Matsubara, N. Miyake, Y. Muraki, M. Nagaya, K. Ohnishi, T. Okumura, Y. Perrott, N. J. Rattenbury, To Saito, T. Sako, S. Sato, L. Skuljan, D. Sullivan, W. Sweatman, P. J. Tristram, P. C.M. Yock, A. Allan, M. F. Bode, M. J. Burgdorf, N. Clay, S. N. Fraser, E. Hawkins, E. Kerins, T. A. Lister, C. J. Mottram, E. S. Saunders, C. Snodgrass, I. A. Steele, P. J. Wheatley, T. Anguita, V. Bozza, K. Harpsøe, T. C. Hinse, M. Hundertmark, P. Kjærgaard, C. Liebig, L. Mancini, G. Masi, S. Rahvar, D. Ricci, G. Scarpetta, J. Southworth, J. Surdej, C. C. Thöne, A. Riffeser, S. Seitz, R. Bender, M. Zub

Facultad Ciencias Exactas

Resultado de la investigación: Contribución a una revista › Artículo

13 Citas (Scopus)

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 V_s- and I_s-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	Inglés
Número de artículo	A51
Publicación	Astronomy and Astrophysics
Volumen	518
N.º	19
DOI	https://doi.org/10.1051/0004-6361/201014053
Estado	Publicada - 2 sep 2010

Áreas temáticas de ASJC Scopus

Astronomía y astrofísica
Ciencias planetarias y espacial

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10.1051/0004-6361/201014053

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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., ... Zub, M. (2010). OGLE 2008-BLG-290: An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing. Astronomy and Astrophysics, 518(19), [A51]. https://doi.org/10.1051/0004-6361/201014053

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. / OGLE 2008-BLG-290 : An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing. En: Astronomy and Astrophysics. 2010 ; Vol. 518, N.º 19.

@article{4b90ba5d2c784c9da421d6c1679cfd8e,

title = "OGLE 2008-BLG-290: An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing",

abstract = "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 Paczy{\'n}ski 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.",

keywords = "Gravitational lensing: micro, Stars: atmospheres, Stars: individual: OGLE 2008-BLG-290, Techniques: high angular resolution",

author = "P. Fouqu{\'e} and D. Heyrovsk{\'y} and S. Dong and A. Gould and A. Udalski and Albrow, {M. D.} and V. Batista and Beaulieu, {J. P.} and Bennett, {D. P.} and Bond, {I. A.} and Bramich, {D. M.} and {Calchi Novati}, S. and A. Cassan and C. Coutures and S. Dieters and M. Dominik and {Dominis Prester}, D. and J. Greenhill and K. Horne and J{\o}rgensen, {U. G.} and S. Koz{\l}owski and D. Kubas and Lee, {C. H.} and Marquette, {J. B.} and M. Mathiasen and J. Menzies and Monard, {L. A.G.} and S. Nishiyama and I. Papadakis and R. Street and T. Sumi and A. Williams and Yee, {J. C.} and S. Brillant and Caldwell, {J. A.R.} and A. Cole and Cook, {K. H.} and J. Donatowicz and N. Kains and Kane, {S. R.} and R. Martin and Pollard, {K. R.} and Sahu, {K. C.} and Y. Tsapras and J. Wambsganss and Depoy, {D. L.} and Gaudi, {B. S.} and C. Han and Lee, {C. U.} and Park, {B. G.} and Pogge, {R. W.} and M. Kubiak and Szyma{\'n}ski, {M. K.} and G. Pietrzy{\'n}ski and I. Soszy{\'n}ski and O. Szewczyk and K. Ulaczyk and L. Wyrzykowski and F. Abe and A. Fukui and K. Furusawa and Gilmore, {A. C.} and Hearnshaw, {J. B.} and Y. Itow and K. Kamiya and Kilmartin, {P. M.} and Korpela, {A. V.} and W. Lin and Ling, {C. H.} and K. Masuda and Y. Matsubara and N. Miyake and Y. Muraki and M. Nagaya and K. Ohnishi and T. Okumura and Y. Perrott and Rattenbury, {N. J.} and To Saito and T. Sako and S. Sato and L. Skuljan and D. Sullivan and W. Sweatman and Tristram, {P. J.} and Yock, {P. C.M.} and A. Allan and Bode, {M. F.} and Burgdorf, {M. J.} and N. Clay and Fraser, {S. N.} and E. Hawkins and E. Kerins and Lister, {T. A.} and Mottram, {C. J.} and Saunders, {E. S.} and C. Snodgrass and Steele, {I. A.} and Wheatley, {P. J.} and T. Anguita and V. Bozza and K. Harps{\o}e and Hinse, {T. C.} and M. Hundertmark and P. Kj{\ae}rgaard and C. Liebig and L. Mancini and G. Masi and S. Rahvar and D. Ricci and G. Scarpetta and J. Southworth and J. Surdej and Th{\"o}ne, {C. C.} and A. Riffeser and S. Seitz and R. Bender and M. Zub",

year = "2010",

month = sep,

day = "2",

doi = "10.1051/0004-6361/201014053",

language = "English",

volume = "518",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

number = "19",

}

Fouqué, P, Heyrovský, D, Dong, S, Gould, A, Udalski, A, Albrow, MD, Batista, V, Beaulieu, JP, Bennett, DP, Bond, IA, Bramich, DM, Calchi Novati, S, Cassan, A, Coutures, C, Dieters, S, Dominik, M, Dominis Prester, D, Greenhill, J, Horne, K, Jørgensen, UG, Kozłowski, S, Kubas, D, Lee, CH, Marquette, JB, Mathiasen, M, Menzies, J, Monard, LAG, Nishiyama, S, Papadakis, I, Street, R, Sumi, T, Williams, A, Yee, JC, Brillant, S, Caldwell, JAR, Cole, A, Cook, KH, Donatowicz, J, Kains, N, Kane, SR, Martin, R, Pollard, KR, Sahu, KC, Tsapras, Y, Wambsganss, J, Depoy, DL, Gaudi, BS, Han, C, Lee, CU, Park, BG, Pogge, RW, Kubiak, M, Szymański, MK, Pietrzyński, G, Soszyński, I, Szewczyk, O, Ulaczyk, K, Wyrzykowski, L, Abe, F, Fukui, A, Furusawa, K, Gilmore, AC, Hearnshaw, JB, Itow, Y, Kamiya, K, Kilmartin, PM, Korpela, AV, Lin, W, Ling, CH, Masuda, K, Matsubara, Y, Miyake, N, Muraki, Y, Nagaya, M, Ohnishi, K, Okumura, T, Perrott, Y, Rattenbury, NJ, Saito, T, Sako, T, Sato, S, Skuljan, L, Sullivan, D, Sweatman, W, Tristram, PJ, Yock, PCM, Allan, A, Bode, MF, Burgdorf, MJ, Clay, N, Fraser, SN, Hawkins, E, Kerins, E, Lister, TA, Mottram, CJ, Saunders, ES, Snodgrass, C, Steele, IA, Wheatley, PJ, Anguita, T, Bozza, V, Harpsøe, K, Hinse, TC, Hundertmark, M, Kjærgaard, P, Liebig, C, Mancini, L, Masi, G, Rahvar, S, Ricci, D, Scarpetta, G, Southworth, J, Surdej, J, Thöne, CC, Riffeser, A, Seitz, S, Bender, R & Zub, M 2010, 'OGLE 2008-BLG-290: An accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing', Astronomy and Astrophysics, vol. 518, n.º 19, A51. https://doi.org/10.1051/0004-6361/201014053

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: Contribución a una revista › Artículo

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 -