Accurate effective temperatures of the metal-poor benchmark stars HD140283, HD122563, and HD103095 from CHARA interferometry

作者：Karovicova I^*; White T R; Nordlander T; Lind K; Casagrande L; Ireland M J; Huber D; Creevey O^*; Mourard D^*; Schaefer G H; Gilmore G; Chiavassa A; Wittkowski M; Jofre P; Heiter U; Thevenin F; Asplund M

来源：Monthly Notices of the Royal Astronomical Society, 2018, 475(1): L81-L85.

DOI：10.1093/mnrasl/sly010

• standards
• techniques: interferometric
• surveys
• stars: individual: HD103095
• stars: individual: HD122563
• stars: individual: HD140283

Large stellar surveys of the MilkyWay require validation with reference to a set of 'benchmark' stars whose fundamental properties are well determined. For metal-poor benchmark stars, disagreement between spectroscopic and interferometric effective temperatures has called the reliability of the temperature scale into question. We present new interferometric measurements of three metal-poor benchmark stars, HD140283, HD122563, and HD103095, from which we determine their effective temperatures. The angular sizes of all the stars were determined from observations with the PAVO beam combiner at visible wavelengths at the CHARA array, with additional observations of HD103095 made with the VEGA instrument, also at the CHARA array. Together with photometrically derived bolometric fluxes, the angular diameters give a direct measurement of the effective temperature. For HD140283, we find theta(LD) = 0.324 +/- 0.005 mas, T-eff = 5787 +/- 48 K; for HD122563,theta(LD) = 0.926 +/- 0.011 mas, T-eff = 4636 +/- 37 K; and for HD103095,theta(LD) = 0.595 +/- 0.007 mas, T-eff = 5140 +/- 49 K. Our temperatures for HD140283 and HD103095 are hotter than the previous interferometric measurements by 253 and 322 K, respectively. We find good agreement between our temperatures and recent spectroscopic and photometric estimates. We conclude some previous interferometric measurements have been affected by systematic uncertainties larger than their quoted errors.

• 出版日期2018-3