LSPM J1112+7626: detection of a 41-day M-dwarf eclipsing binary from the MEarth transit survey

TY - JOUR

T1 - LSPM J1112+7626

T2 - detection of a 41-day M-dwarf eclipsing binary from the MEarth transit survey

AU - Irwin, Jonathan M.

AU - Quinn, Samuel N.

AU - Berta, Zachory K.

AU - Latham, David W.

AU - Torres, Guillermo

AU - Burke, Christopher J.

AU - Charbonneau, David

AU - Dittmann, Jason

AU - Esquerdo, Gilbert A.

AU - Stefanik, Robert P.

AU - Oksanen, Arto

AU - Buchhave, Lars A.

AU - Nutzman, Philip

AU - Berlind, Perry

AU - Calkins, Michael L.

AU - Falco, Emilio E.

PY - 2011/12/1

Y1 - 2011/12/1

N2 - We report the detection of eclipses in LSPM J1112+7626, which we find to be a moderately bright (IC = 12.14 ± 0.05) very low mass binary system with an orbital period of 41.03236 ± 0.00002 days, and component masses M 1 = 0.395 ± 0.002 M ⊙ and M 2 = 0.275 ± 0.001 M ⊙ in an eccentric (e = 0.239 0.002) orbit. A 65 day out-of-eclipse modulation of approximately 2% peak-to-peak amplitude is seen in I-band, which is probably due to rotational modulation of photospheric spots on one of the binary components. This paper presents the discovery and characterization of the object, including radial velocities sufficient to determine both component masses to better than 1% precision, and a photometric solution. We find that the sum of the component radii, which is much better determined than the individual radii, is inflated by 3.8+0.9 -0.5% compared to the theoretical model predictions, depending on the age and metallicity assumed. These results demonstrate that the difficulties in reproducing observed M-dwarf eclipsing binary radii with theoretical models are not confined to systems with very short orbital periods. This object promises to be a fruitful testing ground for the hypothesized link between inflated radii in M-dwarfs and activity.

AB - We report the detection of eclipses in LSPM J1112+7626, which we find to be a moderately bright (IC = 12.14 ± 0.05) very low mass binary system with an orbital period of 41.03236 ± 0.00002 days, and component masses M 1 = 0.395 ± 0.002 M ⊙ and M 2 = 0.275 ± 0.001 M ⊙ in an eccentric (e = 0.239 0.002) orbit. A 65 day out-of-eclipse modulation of approximately 2% peak-to-peak amplitude is seen in I-band, which is probably due to rotational modulation of photospheric spots on one of the binary components. This paper presents the discovery and characterization of the object, including radial velocities sufficient to determine both component masses to better than 1% precision, and a photometric solution. We find that the sum of the component radii, which is much better determined than the individual radii, is inflated by 3.8+0.9 -0.5% compared to the theoretical model predictions, depending on the age and metallicity assumed. These results demonstrate that the difficulties in reproducing observed M-dwarf eclipsing binary radii with theoretical models are not confined to systems with very short orbital periods. This object promises to be a fruitful testing ground for the hypothesized link between inflated radii in M-dwarfs and activity.

U2 - 10.1088/0004-637X/742/2/123

DO - 10.1088/0004-637X/742/2/123

M3 - Journal article

SN - 0004-637X

VL - 742

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 123

ER -