We present analyses of improved photometric and spectroscopic observations for two detached eclipsing binaries at the turnoff of the open cluster NGC 752: the 1.01 days binary DS And and the 15.53 days BD +37 410. For DS And, we find
Stellar radius measurements from eclipsing binaries are typically ∼5% larger than standard stellar models predict. This disagreement means we are unable to derive reliable model-dependent radii, which impact stellar and exoplanet characterization. Using light curves from the TESS satellite and high-resolution, near-infrared spectra from IGRINS, we determine the masses and radii of a main sequence eclipsing binary, V1177 Cen (TIC 3099339). We detrend the light curve using a Gaussian process and derive radial velocities using spectral-line broadening functions, fitting both jointly in an MCMC framework. We find that both stars are near 1
- NSF-PAR ID:
- 10372182
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- Research Notes of the AAS
- Volume:
- 6
- Issue:
- 9
- ISSN:
- 2515-5172
- Format(s):
- Medium: X Size: Article No. 196
- Size(s):
- ["Article No. 196"]
- Sponsoring Org:
- National Science Foundation
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Abstract M 1= 1.692 ± 0.004 ± 0.010M ⊙,R 1= 2.185 ± 0.004 ± 0.008R ⊙,M 2= 1.184 ± 0.001 ± 0.003M ⊙, andR 2= 1.200 ± 0.003 ± 0.005R ⊙. We either confirm or newly identify unusual characteristics of both stars in the binary: the primary star is found to be slightly hotter than the main-sequence turnoff and there is a more substantial discrepancy in its luminosity compared to models (model luminosities are too large by about 40%), while the secondary star is oversized and cooler compared to other main-sequence stars in the same cluster. The evidence points to nonstandard evolution for both stars, but most plausible paths cannot explain the low luminosity of the primary star. BD +37 410 only has one eclipse per cycle, but extensive spectroscopic observations and the Transiting Exoplanet Survey Satellite light curve constrain the stellar masses well:M 1= 1.717 ± 0.011M ⊙andM 2= 1.175 ± 0.005M ⊙. The radius of the main-sequence primary star near 2.9R ⊙definitively requires large convective core overshooting (>0.2 pressure scale heights) in models for its mass, and multiple lines of evidence point toward an age of 1.61 ± 0.03 ± 0.05 Gyr (statistical and systematic uncertainties). Because NGC 752 is currently undergoing the transition from nondegenerate to degenerate He ignition of its red clump stars, BD +37 410 A directly constrains the star mass where this transition occurs. -
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