PLANET observations of microlensing event OGLE-1999-BUL-23: Limb-darkening measurement of the source star

M. D. Albrow; J. An; J. P. Beaulieu; J. A.R. Caldwell; D. L. DePoy; M. Dominik; B. S. Gaudi; A. Gould; J. Greenhill; K. Hill; S. Kane; R. Martin; J. Menzies; R. W. Pogge; K. R. Pollard; P. D. Sackett; K. C. Sahu; P. Vermaak; R. Watson; A. Williams

doi:10.1086/319437

PLANET observations of microlensing event OGLE-1999-BUL-23: Limb-darkening measurement of the source star

M. D. Albrow^*, J. An, J. P. Beaulieu, J. A.R. Caldwell, D. L. DePoy, M. Dominik, B. S. Gaudi, A. Gould, J. Greenhill, K. Hill, S. Kane, R. Martin, J. Menzies, R. W. Pogge, K. R. Pollard, P. D. Sackett, K. C. Sahu, P. Vermaak, R. Watson, A. Williams

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

We present PLANET observations of OGLE-1999-BUL-23, a binary-lens microlensing event toward the Galactic bulge. PLANET observations in the I and V bands cover the event from just before the first caustic crossing until the end of the event. In particular, a densely sampled second caustic crossing enables us to derive the linear limb-darkening coefficients of the source star: c_v = 0.786^+0.080_-0.078 and c_I = 0.632^+0.047_-0.037. Combined analysis of the light curve and the color-magnitude diagram suggests that the source star is a G/K subgiant in the Galactic bulge (T_eff ≃ 4800 K). The resulting linear limb-darkening coefficient of the source is consistent with theoretical predictions, although it is likely that nonlinearity of the stellar surface brightness profile complicates the interpretation, especially for the I band. The global light curve fit to the data indicates that the event is due to a binary lens of a mass ratio q ≃ 0.39 and a projected separation d ≃ 2.42. The lens/source relative proper motion is (22.8 ± 1.5) km s^-1 kpc^-1, typical of bulge/bulge or bulge/disk events.

Original language	English
Pages (from-to)	759-769
Number of pages	11
Journal	Astrophysical Journal
Volume	549
Issue number	2 PART 1
DOIs	https://doi.org/10.1086/319437
Publication status	Published - 10 Mar 2001
Externally published	Yes

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Albrow, M. D., An, J., Beaulieu, J. P., Caldwell, J. A. R., DePoy, D. L., Dominik, M., Gaudi, B. S., Gould, A., Greenhill, J., Hill, K., Kane, S., Martin, R., Menzies, J., Pogge, R. W., Pollard, K. R., Sackett, P. D., Sahu, K. C., Vermaak, P., Watson, R., & Williams, A. (2001). PLANET observations of microlensing event OGLE-1999-BUL-23: Limb-darkening measurement of the source star. Astrophysical Journal, 549(2 PART 1), 759-769. https://doi.org/10.1086/319437

@article{64fe07e401854ed290cfe4104cf1f9ae,

title = "PLANET observations of microlensing event OGLE-1999-BUL-23: Limb-darkening measurement of the source star",

abstract = "We present PLANET observations of OGLE-1999-BUL-23, a binary-lens microlensing event toward the Galactic bulge. PLANET observations in the I and V bands cover the event from just before the first caustic crossing until the end of the event. In particular, a densely sampled second caustic crossing enables us to derive the linear limb-darkening coefficients of the source star: cv = 0.786+0.080-0.078 and cI = 0.632+0.047-0.037. Combined analysis of the light curve and the color-magnitude diagram suggests that the source star is a G/K subgiant in the Galactic bulge (Teff ≃ 4800 K). The resulting linear limb-darkening coefficient of the source is consistent with theoretical predictions, although it is likely that nonlinearity of the stellar surface brightness profile complicates the interpretation, especially for the I band. The global light curve fit to the data indicates that the event is due to a binary lens of a mass ratio q ≃ 0.39 and a projected separation d ≃ 2.42. The lens/source relative proper motion is (22.8 ± 1.5) km s-1 kpc-1, typical of bulge/bulge or bulge/disk events.",

keywords = "Binaries: general, Gravitational lensing, Stars: atmospheres, Stars: fundamental parameters",

author = "Albrow, {M. D.} and J. An and Beaulieu, {J. P.} and Caldwell, {J. A.R.} and DePoy, {D. L.} and M. Dominik and Gaudi, {B. S.} and A. Gould and J. Greenhill and K. Hill and S. Kane and R. Martin and J. Menzies and Pogge, {R. W.} and Pollard, {K. R.} and Sackett, {P. D.} and Sahu, {K. C.} and P. Vermaak and R. Watson and A. Williams",

year = "2001",

month = mar,

day = "10",

doi = "10.1086/319437",

language = "English",

volume = "549",

pages = "759--769",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2 PART 1",

}

Albrow, MD, An, J, Beaulieu, JP, Caldwell, JAR, DePoy, DL, Dominik, M, Gaudi, BS, Gould, A, Greenhill, J, Hill, K, Kane, S, Martin, R, Menzies, J, Pogge, RW, Pollard, KR, Sackett, PD, Sahu, KC, Vermaak, P, Watson, R & Williams, A 2001, 'PLANET observations of microlensing event OGLE-1999-BUL-23: Limb-darkening measurement of the source star', Astrophysical Journal, vol. 549, no. 2 PART 1, pp. 759-769. https://doi.org/10.1086/319437

TY - JOUR

T1 - PLANET observations of microlensing event OGLE-1999-BUL-23

T2 - Limb-darkening measurement of the source star

AU - Albrow, M. D.

AU - An, J.

AU - Beaulieu, J. P.

AU - Caldwell, J. A.R.

AU - DePoy, D. L.

AU - Dominik, M.

AU - Gaudi, B. S.

AU - Gould, A.

AU - Greenhill, J.

AU - Hill, K.

AU - Kane, S.

AU - Martin, R.

AU - Menzies, J.

AU - Pogge, R. W.

AU - Pollard, K. R.

AU - Sackett, P. D.

AU - Sahu, K. C.

AU - Vermaak, P.

AU - Watson, R.

AU - Williams, A.

PY - 2001/3/10

Y1 - 2001/3/10

N2 - We present PLANET observations of OGLE-1999-BUL-23, a binary-lens microlensing event toward the Galactic bulge. PLANET observations in the I and V bands cover the event from just before the first caustic crossing until the end of the event. In particular, a densely sampled second caustic crossing enables us to derive the linear limb-darkening coefficients of the source star: cv = 0.786+0.080-0.078 and cI = 0.632+0.047-0.037. Combined analysis of the light curve and the color-magnitude diagram suggests that the source star is a G/K subgiant in the Galactic bulge (Teff ≃ 4800 K). The resulting linear limb-darkening coefficient of the source is consistent with theoretical predictions, although it is likely that nonlinearity of the stellar surface brightness profile complicates the interpretation, especially for the I band. The global light curve fit to the data indicates that the event is due to a binary lens of a mass ratio q ≃ 0.39 and a projected separation d ≃ 2.42. The lens/source relative proper motion is (22.8 ± 1.5) km s-1 kpc-1, typical of bulge/bulge or bulge/disk events.

AB - We present PLANET observations of OGLE-1999-BUL-23, a binary-lens microlensing event toward the Galactic bulge. PLANET observations in the I and V bands cover the event from just before the first caustic crossing until the end of the event. In particular, a densely sampled second caustic crossing enables us to derive the linear limb-darkening coefficients of the source star: cv = 0.786+0.080-0.078 and cI = 0.632+0.047-0.037. Combined analysis of the light curve and the color-magnitude diagram suggests that the source star is a G/K subgiant in the Galactic bulge (Teff ≃ 4800 K). The resulting linear limb-darkening coefficient of the source is consistent with theoretical predictions, although it is likely that nonlinearity of the stellar surface brightness profile complicates the interpretation, especially for the I band. The global light curve fit to the data indicates that the event is due to a binary lens of a mass ratio q ≃ 0.39 and a projected separation d ≃ 2.42. The lens/source relative proper motion is (22.8 ± 1.5) km s-1 kpc-1, typical of bulge/bulge or bulge/disk events.

KW - Binaries: general

KW - Gravitational lensing

KW - Stars: atmospheres

KW - Stars: fundamental parameters

UR - http://www.scopus.com/inward/record.url?scp=0035836107&partnerID=8YFLogxK

U2 - 10.1086/319437

DO - 10.1086/319437

M3 - Article

SN - 0004-637X

VL - 549

SP - 759

EP - 769

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART 1

ER -

PLANET observations of microlensing event OGLE-1999-BUL-23: Limb-darkening measurement of the source star

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