Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2008.08371

Benchmark stars, benchmark spectrographs: Detailed spectroscopic comparison of ESPRESSO, PEPSI, and HARPS data for Gaia benchmark stars

V. Adibekyan·S. G. Sousa·N. C. Santos·P. Figueira·C. Allende Prieto·E. Delgado Mena·J. I. Gonzaalez Hernaandez·P. de Laverny·A. Recio-Blanco·T. L. Campante·M. Tsantaki·A. A. Hakobyan·M. Oshagh·J. P. Faria·M. Bergemann·G. Israelian·T. Boule
View original source ↗Read source document ↗Export metadata ↓

Abstract

Gaia benchmark stars are selected to be calibration stars for different spectroscopic surveys. Very high-quality and homogeneous spectroscopic data for these stars are therefore required. We collected ultrahigh-resolution ESPRESSO spectra for 30 of the 34 Gaia benchmark stars and made them public. We quantify the consistency of the results that are obtained with different high-, and ultrahigh-resolution spectrographs. We also comprehensively studied the effect of using different spectral reduction products of ESPRESSO on the final spectroscopic results. We used ultrahigh- and high-resolution spectra obtained with the ESPRESSO, PEPSI, and HARPS spectrographs to measure spectral line characteristics (line depth; line width; and EW) and determined stellar parameters and abundances for a subset of 11 Gaia benchmark stars. We used the ARES code for automatic measurements of the spectral line parameters. Our measurements reveal that the same individual spectral lines measured from adjacent 2D echelle orders of ESPRESSO spectra differ slightly in line depth and line width. When a long list of spectral lines is considered, the EW measurements based on the 2D and 1D (the final spectral product) ESPRESSO spectra agree very well. The EW spectral line measurements based on the ESPRESSO, PEPSI, and HARPS spectra also agree to within a few percent. However, we note that the lines appear deeper in the ESPRESSO spectra than in PEPSI and HARPS. The stellar parameters derived from each spectrograph by combining the several available spectra agree well overall. We conclude that the ESPRESSO, PEPSI, and HARPS spectrographs can deliver spectroscopic results that are sufficiently consistent for most of the science cases in stellar spectroscopy. However, we found small but important differences in the performance of the three spectrographs that can be crucial for specific science cases.

Explore related subjects

astro-ph.SRastro-ph.IM

Keep this discovery

BibTeXRIS

V. Adibekyan, S. G. Sousa, N. C. Santos, P. Figueira, C. Allende Prieto, E. Delgado Mena, J. I. Gonzaalez Hernaandez, P. de Laverny, A. Recio-Blanco, T. L. Campante, M. Tsantaki, A. A. Hakobyan, M. Oshagh, J. P. Faria, M. Bergemann, G. Israelian, T. Boule. 2020-08-19. Benchmark stars, benchmark spectrographs: Detailed spectroscopic comparison of ESPRESSO, PEPSI, and HARPS data for Gaia benchmark stars. https://doi.org/10.1051/0004-6361%2F202038793

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Eclipse Properties and Superhump Evolution in the SU UMa-Type Dwarf Nova Z Cha

The advent of large-scale time-domain surveys provides both opportunities and challenges for understanding accretion disk evolution in cataclysmic variables (CVs). Using high-cadence photometry from the Transiting Exoplanet Survey Satellite (TESS), we investigate the eclipsing SU UMa-type dwarf nova Z Cha. Leveraging eclipses as a natural probe, we examine the evolution of the accretion disk through variations in eclipse depth, O--C of eclipse minima, and positive superhump (PSH) amplitude. During superoutbursts, all three quantities exhibit quasi-periodic modulations with a common period of $\sim$2 days, consistent with the precession period of an eccentric disk. We interpret these correlated variations as evidence of an eccentric, precessing disk: O--C traces the periodic shift of the system's brightness center, while eclipse depth and PSH amplitude vary with the orientation of the disk bulge relative to the line of sight. In quiescence (Sectors 13 and 93), PSHs with periods of $\sim$0.0762 days show linearly decreasing amplitudes and periods, indicating gradual shrinkage of the eccentric disk and a slowing precession. Remarkably, a coherent signal with a period of $\sim$0.0729~days ($\epsilon^{-}\approx-0.02$) appears in the same quiescent intervals. This signal may represent negative superhumps (NSHs) coexisting with PSHs, although an orbital sideband of the PSH cannot presently be excluded with the available data. If confirmed as NSHs, their coexistence with PSHs would challenge the classical tilted-disk model, and could be explained by retrograde apsidal precession of an eccentric disk, where the inner disk precesses retrogradely (NSHs) and the outer disk progradely (PSHs); this interpretation remains to be tested by further observations.

astro-ph.SR↗
arXiv2026

Classical Nova V1405 Cas Had $M_{\rm ejecta}$$>$$M_{\rm accreted}$ and so is Unlikely to be a Type Ia Supernova Progenitor

Nova 2021 Cassiopeia (V1405 Cas) was an ordinary J(175) neon nova with the white dwarf mass estimated to be $M_{\rm WD}$=0.60$\pm$0.10 $M_{\odot}$. I found an orbital period of $P$=0.1884 days, and have tracked 20 times of photometric minima from 2013--2025. I measure that $P$ increased from before to after the eruption with $P_{\rm pre}$=0.1883919$\pm$0.0000018 days and $P_{\rm post}$=0.1884043$\pm$0.0000018 days, for $\Delta P$/$P$=66$_{-18}^{+21}$ parts-per-million. With correction for the angular momentum loss by the binary during the eruption, I derive that the nova ejected $M_{\rm ejecta}$=7.5$\times$10$^{-4}$ $M_{\odot}$, with an extreme range of (2.9--40)$\times$10$^{-4}$ $M_{\odot}$. The mass accreted during the previous eruption cycle comes from the trigger mass, and is $M_{\rm accreted}$=(1.6$\pm$0.4)$\times$10$^{-4}$ $M_{\odot}$. V1405 Cas provides counterexamples against five claims about CV evolution that have dominated since the 1980s. First, V1405 Cas has positive $\dot{P}$, and this is contrary to the Magnetic Braking Model. Second, the $\Delta P$ is 20$\times$ too small to allow the system to fade into a hibernation state. Third, $M_{\rm WD}$ is decreasing over time, as shown by $M_{\rm ejecta}$$>$$M_{\rm accreted}$ and by being a neon nova. Fourth, V1405 Cas is not a Type Ia supernova progenitor, for the same reasons. Fifth, the orbital period of V1405 Cas increased by $+$75 ppm from 2013--2025, as a counterexample to the pervasive idea that cataclysmic variables are universally declining in period from evolution. V1405 Cas is the latest of recent measures of $\Delta P$ and $\dot{P}$ for 52 cataclysmic variables and 25 X-ray binaries that have together refuted all five claims.

astro-ph.SR↗
arXiv2026

A prolonged plateau-to-tail transition in the Type II supernova SN2025abyc

We present optical photometric and spectroscopic observations of the Type II supernova SN2025abyc. During the optically thick phase between approximately 10 and 70 d after explosion, its light curves show strongly wavelength-dependent decline rates of approximately 2.7, 2.1, 0.9, and 0.8 mag/100d in the g, c, r, and o bands, respectively. At approximately 70 d, the light curves begin to depart from their nearly linear plateau evolution and gradually transition toward the radioactive tail. A Fermi-Dirac fit to the well-sampled ATLAS o-band light curve yields a transition midpoint of t_PT ~ 100.5d. The interval between the end of the linear plateau and this transition midpoint is approximately 30 d, indicating a prolonged plateau-to-tail transition. This timescale is comparable to those measured for SN2013by, SN2013ej, and SN2014G. Spectroscopically, at +13 d post-explosion, the Halpha profile appears weak and broad, whereas Hbeta and Hgamma display clear P-Cygni profiles. This morphology can be explained by the normal early spectroscopic evolution of SNe II, although partial filling of the Halpha absorption trough by emission associated with circumstellar interaction cannot be excluded. SN2025abyc otherwise follows the general photospheric velocity evolution of SNe II, while remaining toward the high-velocity side of the comparison distribution in Halpha, Hbeta, and FeII. Exploratory light-curve modelling suggests a synthesized Ni mass of approximately 0.03-0.04 solar mass. We suggest that the extended circumstellar environment, Ni distribution, and hydrogen-envelope structure could all play a role in shaping the observed light-curve evolution, particularly the prolonged plateau-to-tail transition.

astro-ph.SR↗