Astroserver – Research Services in the Stellar Webshop

Abstract

Abstract:A quick look at research and development in astronomy shows that we live in exciting times. Exoplanetary systems, supernovae, and merging binary black holes were far out of reach for observers two decades ago and now such phenomena are recorded routinely. This quick development would not have been possible without the ability for researchers to be connected, to think globally and to be mobile. Classical short-term positions are not always suitable to support these conditions and freelancing may be a viable alternative. We introduce the Astroserver framework, which is a new freelancing platform for scientists, and demonstrate through examples how it contributed to some recent projects related to hot subdwarf stars and binaries. These contributions, which included spectroscopic data mining, computing services and observing services, as well as artwork, allowed a deeper look into the investigated systems. The work on composite spectra binaries provided new details for the hypervelocity wide subdwarf binary PB 3877 and found diverse and rare systems with sub-giant companions in high-resolution spectroscopic surveys. The models for the peculiar abundance pattern of the evolved compact star LP 40-365 showed it to be a bound hypervelocity remnant of a supernova Iax event. Some of these works also included data visualizations to help presenting the new results. Such services may be of interest for many researchers.

Hot Subdwarf All Southern Sky Fast Transit Survey with the Evryscope

“…We detect strong H Balmer lines in all variability candidates and He lines in many. Each spectrum was visually inspected and fitted using the stellar atmosphere model service for early type stars from Astroserver 5 (Németh 2017). From the best fits, we measure the effective temperature, surface gravity, projected rotational velocity, helium abundance and approximate the metallicity.…”

“…From the best fit to the SOAR ID spectra using Astroserver (Németh 2017), we measure T eff = 31, 980K, log g = 5.78 cm s −2 . We classify EC 01578-1743 as an sdB, and identify it as a reflection effect HSD binary.…”

Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra

“…Pulsating sdO/B stars allow the accurate determination of mass and internal structure by using asteroseismic methods, which provide excellent tests for the formation and evolution models (Kawaler et al 2010;Charpinet et al 2011;Baran et al 2012;Battich et al 2018;Zong et al 2018). The diversity of atmospheres in hot subdwarf stars makes them good samples to study atomic diffusion processes (Moehler et al 2014;Jeffery et al 2017;Németh 2017;Byrne et al 2018;Naslim et al 2013Naslim et al , 2019. In addition, hot subdwarf stars in Globular Clusters (GCs) provide useful information to understand the formation and evolution of the oldest populations in our galaxy (Lei et al 2015(Lei et al , 2016Latour et al 2014Latour et al , 2018.…”

New Hot Subdwarf Stars Identified in Gaia DR2 with LAMOST DR5 Spectra. II.

“…Pulsating hot subdwarfs studied by asteroseismology give insights into their interior structures (Kawaler et al 2010;Charpinet et al 2011;Baran et al 2012;Battich et al 2018;Zong et al 2018). Furthermore, the variety of surface chemical compositions in hot subdwarfs stars make them good samples to study atmotic diffusion processes (Hu et al 2009(Hu et al , 2010(Hu et al , 2011Naslim et al 2013;Moehler et al 2014;Jeffery et al 2017;Németh 2017;Byrne et al 2018). Study on the counterparts of field hot subdwarfs in GCs (e.g., EHB stars) can help us understand the formation history and evolution processes of these old populations (Lei et al 2015(Lei et al , 2016Latour et al 2014Latour et al , 2018.…”