Ongoing astrometric microlensing events of two nearby stars

被引：11

作者：

Klueter, J. ^{[1
]}

Bastian, U. ^{[1
]}

Demleitner, M. ^{[1
]}

Wambsganss, J. ^{[1
,2
]}

机构：

[1] Heidelberg Univ, Zentrum Astron, Astronom Rechen Inst, Monchhofstr 12, D-69120 Heidelberg, Germany

[2] Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland

来源：

ASTRONOMY & ASTROPHYSICS | 2018年 / 615卷

基金：

美国国家科学基金会; 美国国家航空航天局;

关键词：

astrometry; proper motions; catalogs; gravitational lensing: micro;

D O I：

10.1051/0004-6361/201833461

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Context. Astrometric microlensing is an excellent tool to determine the mass of stellar objects. By measuring the astrometric shift of a background source star in combination with precise predictions of its unlensed position and of the lens position, gravitational lensing allows to one determine the mass of the lensing star with a precision of 1%, independently of any prior knowledge. Aims. Making use of the recently published Gaia Data Release 2 (Gaia DR2) we predict astrometric microlensing events by foreground stars of high proper motion passing by a background star in the coming years. Methods. We compile a list of approximately 148 000 high-proper-motion stars within Gaia DR2 with mu(tot) > 150 mas yr(-1). We then search for background stars close to their paths and calculate the dates and separations of the closest approaches. Using color and absolute magnitude, we determine approximate masses of the lenses. Finally, we calculate the expected astrometric shifts and magnifications of the predicted events. Results. We detect two ongoing microlensing events by the high-proper-motion stars Luyten 143-23 and Ross 322 and predict closest separations of (108.5 +/- 1.4) mas in July 2018 and (125.3 +/- 3.4) mas in August 2018, respectively. The respective expected astrometric shifts are (1.74 +/- 0.12) mas and (0.76 +/- 0.06) mas. Furthermore, Luyten 143-23 will pass by another star in March 2021 with a closest separation of (280.1 +/- 1.1) mas, which results in an expected shift of (0.69 +/- 0.05) mas.

引用

页数：4

共 14 条

[1]

ABUTER R, 2017, A A, V602

[2] Gaia Data Release 2. Summary of the contents and survey properties [J].

Brown, A. G. A. ;

Vallenari, A. ;

Prusti, T. ;

de Bruijne, J. H. J. ;

Babusiaux, C. ;

Bailer-Jones, C. A. L. ;

Biermann, M. ;

Evans, D. W. ;

Eyer, L. ;

Jansen, F. ;

Jordi, C. ;

Klioner, S. A. ;

Lammers, U. ;

Lindegren, L. ;

Luri, X. ;

Mignard, F. ;

Panem, C. ;

Pourbaix, D. ;

Randich, S. ;

Sartoretti, P. ;

Siddiqui, H. I. ;

Soubiran, C. ;

van Leeuwen, F. ;

Walton, N. A. ;

Arenou, F. ;

Bastian, U. ;

Cropper, M. ;

Drimmel, R. ;

Katz, D. ;

Lattanzi, M. G. ;

Bakker, J. ;

Cacciari, C. ;

Castaneda, J. ;

Chaoul, L. ;

Cheek, N. ;

De Angeli, F. ;

Fabricius, C. ;

Guerra, R. ;

Holl, B. ;

Masana, E. ;

Messineo, R. ;

Mowlavi, N. ;

Nienartowicz, K. ;

Panuzzo, P. ;

Portell, J. ;

Riello, M. ;

Seabroke, G. M. ;

Tanga, P. ;

Thevenin, F. ;

Gracia-Abril, G. .

ASTRONOMY & ASTROPHYSICS, 2018, 616

[3]

Chambers K.C., 2018, AAS M

[4] Gaia broad band photometry [J].

Jordi, C. ;

Gebran, M. ;

Carrasco, J. M. ;

de Bruijne, J. ;

Voss, H. ;

Fabricius, C. ;

Knude, J. ;

Vallenari, A. ;

Kohley, R. ;

Mora, A. .

ASTRONOMY & ASTROPHYSICS, 2010, 523

[5] Microlensing Constraints on the Mass of Single Stars from HST Astrometric Measurements [J].

Kains, N. ;

Calamida, A. ;

Sahu, K. C. ;

Casertano, S. ;

Anderson, J. ;

Udalski, A. ;

Zoccali, M. ;

Bond, H. ;

Albrow, M. ;

Bond, I. ;

Brown, T. ;

Dominik, M. ;

Fryer, C. ;

Livio, M. ;

Mao, S. ;

Rejkuba, M. .

ASTROPHYSICAL JOURNAL, 2017, 843 (02)

[6] A predicted astrometric microlensing event by a nearby white dwarf [J].

McGill, Peter ;

Smith, Leigh C. ;

Evans, N. Wyn ;

Belokurov, Vasily ;

Smart, R. L. .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2018, 478 (01) :L29-L33

[7]

PACZYNSKI B, 1995, ACTA ASTRONOM, V45, P345

[8] Gravitational microlensing with the Space Interferometry Mission [J].

Paczynski, B .

ASTROPHYSICAL JOURNAL, 1998, 494 (01) :L23-L26

[9] INTRINSIC COLORS, TEMPERATURES, AND BOLOMETRIC CORRECTIONS OF PRE-MAIN-SEQUENCE STARS [J].

Pecaut, Mark J. ;

Mamajek, Eric E. .

ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 2013, 208 (01)

[10] Prediction of astrometric microlensing events during the Gaia mission [J].

Proft, S. ;

Demleitner, M. ;

Wambsganss, J. .

ASTRONOMY & ASTROPHYSICS, 2011, 536

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