High-resolution Spectroscopy and Spectropolarimetry of Some Late F- / Early G-type Sun-like Stars as Targets for Zeeman Doppler Imaging

Abstract

High-resolution spectroscopy and spectropolarimetry have been undertaken at the AngloAustralian Telescope in order to identify suitable targets for magnetic studies of young Sun-like stars, for the proxy study of early solar evolution. This study involved the investigation of some variable late F-/ early G-type Sun-like stars originally identified by the Hipparcos mission. Of the 38 stars observed for this study, HIP 31021, HIP 64732, HIP 73780 were found to be spectroscopic binary stars, while HIP 19072, HIP 67651 and HIP 75636 are also likely to be binaries and HIP 33111 could even be a triple system. Magnetic fields were detected on a number of the survey stars: HIP 21632, HIP 43720, HIP 48770, HIP 62517, HIP 71933, HIP 77144, HIP 89829, HIP 90899 and HIP 105388, making these stars good candidates for follow-up Zeeman Doppler imaging studies.

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

“…Indication of binarity comes also from the astrometric acceleration detected by Hipparcos. The small v sin i quoted by Nordström et al (2004) (2 km s −1 ) is highly discrepant with the fast rotation reported by Waite et al (2011) and with our own spectrum (70 km s −1 ). The Nordström et al (2004) RV measurement should therefore be taken with caution.…”

“…However, the deformation of the line profile might also be due to spots. This issue was also discussed by Waite et al (2011), who favor the star-spot interpretation. We therefore consider this star as only a possible binary.…”

“…We adopt the isochrone age of the primary. HIP 71933 = HD 129181 (ASAS 144244−4848.0) RV measurements from SACY, Nordström et al (2004), Waite et al (2011) and our FEROS spectrum show a rather large scatter (4 km s −1 ), suggesting binarity. Indication of binarity comes also from the astrometric acceleration detected by Hipparcos.…”

“…No period is found in the Hipparcos data. According to Waite et al (2011), the star is likely single, with line profile variations most likely due to star spots. HIP 93375 (ASAS 190106−2842.8) Proposed by Torres et al (2008) as a high-probability member of AB Dor.…”

Citations to Australian Astronomy: 5- and 10-Year Benchmarks

“…Bains et al 2009;Robertson et al 2010;Waite et al 2011) would have all contributed to those papers, while the lead-author will have likely performed the bulk of the work. Figure 3 shows the normalized citation count (a sorting option within ADS in which each article's total citation count is divided by the number of contributing authors), and an individuals total citation count when they are the lead-author (achieved by placing the carat symbol,^, in front of an author's name within the ADS web-form).…”