The TESS Input Catalog and Candidate Target List

Ramsay

Monthly Notices of the Royal Astronomical Society

2020

Superflares on solar-type stars has been a rapidly developing field ever since the launch of Kepler. Over the years, there have been several studies investigating the statistics of these explosive events. In this study, we present a statistical analysis of stellar flares on solar-type stars made using photometric data in 2-min cadence from TESS of the whole southern hemisphere (sectors 1 -13). We derive rotational periods for all stars in our sample from rotational modulations present in the lightcurve as a result of large starspot(s) on the surface. We identify 1980 stellar flares from 209 solar-type stars with energies in the range of 10 31 − 10 36 erg (using the solar flare classification, this corresponds to X1 -X100,000) and conduct an analysis into their properties. We investigate the rotational phase of the flares and find no preference for any phase suggesting the flares are randomly distributed. As a benchmark, we use GOES data of solar flares to detail the close relationship between solar flares and sunspots. In addition, we also calculate approximate spot areas for each of our stars and compare this to flare number, rotational phase and flare energy. Additionally, two of our stars were observed in the continuous viewing zone with lightcurves spanning one year, as a result we examine the stellar variability of these stars in more detail.

Section: Stellar Flaresmentioning

confidence: 99%

Superflares and variability in solar-type stars with TESS in the Southern hemisphere

Ramsay

Monthly Notices of the Royal Astronomical Society

2020

“…After the TESS input catalog release, we identified the targets in the TIC and used the log g in the catalog (Stassun et al 2018) ( Fig. 1-c).…”

Section: Sampled M-dwarfsmentioning

confidence: 99%

Catalog for the ESPRESSO blind radial velocity exoplanet survey

Hojjatpanah

Figueira

Santos

et al. 2019

A&A

Aims. One of the main scientific drivers for ESPRESSO,Échelle SPectrograph, is the detection and characterization of Earth-class exoplanets. With this goal in mind, the ESPRESSO Guaranteed Time Observations (GTO) Catalog identifies the best target stars for a blind search for the radial velocity (RV) signals caused by Earth-class exoplanets. Methods. Using the most complete stellar catalogs available, we screened for the most suitable G, K, and M dwarf stars for the detection of Earth-class exoplanets with ESPRESSO. For most of the stars, we then gathered high-resolution spectra from new observations or from archival data. We used these spectra to spectroscopically investigate the existence of any stellar binaries, both bound or background stars. We derived the activity level using chromospheric activity indexes using log(R HK ), as well as the projected rotational velocity v sin i. For the cases where planet companions are already known, we also looked at the possibility that additional planets may exist in the host's habitable zone using dynamical arguments. Results. We estimated the spectroscopic contamination level, v sin i, activity, stellar parameters and chemical abundances for 249 of the most promising targets. Using these data, we selected 45 stars that match our criteria for detectability of a planet like Earth. The stars presented and discussed in this paper constitute the ESPRESSO GTO catalog for the RV blind search for Earth-class planets. They can also be used for any other work requiring a detailed spectroscopic characterization of stars in the solar neighborhood.

Monthly Notices of the Royal Astronomical Society

“…References. Gaia: Gaia Collaboration et al (2018); G14: Gaidos et al (2014); 2MASS: Skrutskie et al (2006); H02: Henry et al (2002); S18: Stassun et al (2018); N14: Neves et al (2014); R74: Rodgers & Eggen (1974); B14: Barnes et al (2014); S04: Schmitt & Liefke (2004); W08: West et al (2008).…”

Section: General Properties Of Gj 1061mentioning

confidence: 99%

RedDots: a temperate 1.5 Earth-mass planet candidate in a compact multiterrestrial planet system around GJ 1061

Dreizler

Jeffers

Rodrı́guez

et al. 2020

Small low-mass stars are favourable targets for the detection of rocky habitable planets. In particular, planetary systems in the solar neighbourhood are interesting and suitable for precise characterisation. The Red Dots campaigns seek to discover rocky planets orbiting nearby low-mass stars. The 2018 campaign targeted GJ 1061, which is the 20 th nearest star to the Sun. For three consecutive months we obtained nightly, highprecision radial velocity measurements with the HARPS spectrograph. We analysed these data together with archival HARPS data. We report the detection of three planet candidates with periods of 3.204 ± 0.001, 6.689 ± 0.005 and 13.03 ± 0.03 days, which is close to 1:2:4 period commensurability. After several considerations related to the properties of the noise and sampling, we conclude that a 4 th signal is most likely explained by stellar rotation, although it may be due to a planet. The proposed threeplanet system (and the potential four-planet solution) is long-term dynamically stable. Planet-planet gravitational interactions are below our current detection threshold. The minimum masses of the three planets range from 1.4±0.2 to 1.8±0.3 M ⊕ . Planet d, with m sin i = 1.68 ± 0.25M ⊕ , receives a similar amount of energy as Earth receives from the Sun. Consequently it lies within the liquid-water habitable zone of the star and has a similar equilibrium temperature to Earth. GJ 1061 has very similar properties to Proxima Centauri but activity indices point to lower levels of stellar activity.