Investigating three Sirius-like systems with SPHERE

Author(s):Show less -

Gratton, R. ^[1] ; D'Orazi, V ^[1] ; Pacheco, T. A. ^[2] ; Zurlo, A. ^{[3, 4, 5]} ; Desidera, S. ^[1] ; Melendez, J. ^[2] ; Mesa, D. ^[1] ; Claudi, R. ^[1] ; Janson, M. ^{[6, 7]} ; Langlois, M. ^{[5, 8]} ; Rickman, E. ^[9] ; Samland, M. ^{[6, 7]} ; Moulin, T. ^[10] ; Soenke, C. ^[11] ; Cascone, E. ^[12] ; Ramos, J. ^[6] ; Rigal, F. ^[13] ; Avenhaus, H. ^[14] ; Beuzit, J. L. ^{[10, 5]} ; Biller, B. ^{[6, 15]} ; Boccaletti, A. ^[16] ; Bonavita, M. ^{[1, 15]} ; Bonnefoy, M. ^[10] ; Brandner, W. ^[6] ; Chauvin, G. ^{[17, 10, 18]} ; Cudel, M. ^[10] ; Daemgen, S. ^[14] ; Delorme, P. ^[10] ; Desgrange, C. ^{[3, 8]} ; Engler, N. ^[14] ; Feldt, M. ^[6] ; Fontanive, C. ^{[1, 19]} ; Galicher, R. ^[16] ; Garufi, A. ^{[14, 20]} ; Gasparri, D. ^[21] ; Ginski, C. ^[22] ; Girard, J. ^[23] ; Hagelberg, J. ^[24] ; Hunziker, S. ^[14] ; Kasper, M. ^[11] ; Keppler, M. ^[6] ; Lagrange, A-M ^{[10, 16]} ; Lannier, J. ^[10] ; Lazzoni, C. ^[1] ; Le Coroller, H. ^[5] ; Ligi, R. ^{[25, 26]} ; Lombart, M. ^{[17, 8, 18]} ; Maire, A-L ^{[6, 27]} ; Mayer, M. R. ^{[28, 14]} ; Mazevet, S. ^[29] ; Menard, F. ^[10] ; Mouillet, D. ^[10] ; Perrot, C. ^{[16, 30, 31]} ; Peretti, S. ^[24] ; Petrus, S. ^[10] ; Potier, A. ^[16] ; Rouan, D. ^[10] ; Schmid, H. M. ^[14] ; Schmidt, T. O. B. ^[16] ; Sissa, E. ^[1] ; Stolker, T. ^[32] ; Salter, G. ^[5] ; Vigan, A. ^[5] ; Wildi, F. ^[24]

Affiliation:Show less -

^[1] INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua - Italy

^[2] Univ Sao Paulo, Dept Astron, IAG USP, Rua Matao 1226, BR-05508900 Sao Paulo, SP - Brazil

^[3] Univ Diego Portales, Fac Ingn, Nucleo Astron, Av Ejercito 441, Santiago - Chile

^[4] Univ Diego Portales, Fac Ingn & Ciencias, Escuela Ingn Ind, Av Ejercito 441, Santiago - Chile

^[5] Aix Marseille Univ, CNRS, LAM Lab Astrophys Marseille, UMR 7326, F-13388 Marseille - France

^[6] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg - Germany

^[7] Stockholm Univ, AlbaNova Univ Ctr, Dept Astron, S-10691 Stockholm - Sweden

^[8] Univ Lyon 1, CRAL, UMR 5574, CNRS, 9 Ave Charles Andre, F-69561 St Genis Laval - France

^[9] European Space Agcy ESA, ESA Off, Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 - USA

^[10] Univ Grenoble Alpes, IPAG, CNRS, F-38000 Grenoble - France

^[11] European Southern Observ ESO, Karl Schwarzschild Str 2, D-85748 Garching - Germany

^[12] INAF Osservatorio Astron Capodimonte, Salita Moiariello 16, I-80131 Naples - Italy

^[13] NOVA Opt Infrared Instrumentat Grp, Oude Hoogeveensedijk 4, NL-7991 PD Dwingeloo - Netherlands

^[14] Swiss Fed Inst Technol, Inst Particle Phys & Astrophys, Wolfgang Pauli Str 27, CH-8093 Zurich - Switzerland

^[15] Univ Edinburgh, Inst Astron, Edinburgh EH9 3HJ, Midlothian - Scotland

^[16] Univ Paris Diderot, Observ Paris, Sorbonne Paris Cite, Sorbonne Univ, CNRS, Univ PSL, LESIA, 5 Pl Jules Janssen, F-92195 Meudon - France

^[17] Univ Chile, Dept Astron, Casilla 36-D, Santiago - Chile

^[18] Univ Chile, Unidad Mixta Int Franco Chilena Astron, Casilla 36, Santiago - Chile

^[19] Univ Bern, Ctr Space & Habitabil, CH-3012 Bern - Switzerland

^[20] INAF Osservatorio Astrofis Arcetri, Florence - Italy

^[21] Univ Atacama, INCT, Calle Copayapu 485, Copiapo, Atacama - Chile

^[22] Leiden Univ, Leiden Observ, POB 9513, NL-2300 RA Leiden - Netherlands

^[23] European Southern Observ, Alonso de Cordova 3107, Casilla 19001 Vitacura, Santiago 19 - Chile

^[24] Univ Geneva, Geneva Observ, Chemin Mailettes 51, CH-1290 Versoix - Switzerland

^[25] INAF Osservatorio Astron Brera, Milan - Italy

^[26] Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Blvd Observ, CS 34229, F-06304 Nice 4 - France

^[27] Univ Liege, STAR Inst, Allee Six Aout 19c, B-4000 Liege - Belgium

^[28] Univ Michigan, Dept Astron, 1085 S Univ, Ann Arbor, MI 48109 - USA

^[29] PSL Univ, Observ Paris, Lab Univers & Theories, Univ Paris Diderot, 5 Pl Jules Janssen, F-92195 Meudon - France

^[30] Univ Valparaiso, Fac Ciencias, Inst Fis & Astron, Av Gran Bretana 1111, Valparaiso - Chile

^[31] Univ Valparaiso, Nucleo Milenio Formac Planetaria NPR, Av Gran Bretana 1111, Valparaiso - Chile

^[32] Univ Amsterdam, Anton Pannekoek Inst Astron, Sci Pk 904, NL-1098 XH Amsterdam - Netherlands

• Document type: Journal article
• Source: Astronomy & Astrophysics; v. 646, FEB 5 2021.
• Web of Science Citations: 0

Abstract

Context. Sirius-like systems are relatively wide binaries with a separation from a few to hundreds of au; they are composed of a white dwarf (WD) and a companion of a spectral type earlier than M0. Here we consider main sequence (MS) companions, where the WD progenitor evolves in isolation, but its wind during the former asymptotic giant branch (AGB) phase pollutes the companion surface and transfers some angular momentum. They are rich laboratories to constrain stellar models and binary evolution.Aims. Within the SpHere INfrared survey for Exoplanet survey that uses the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument at the Very Large Telescope, our goal is to acquire high contrast multi-epoch observations of three Sirius-like systems, HD 2133, HD 114174, and CD-56 7708 and to combine this data with archive high resolution spectra of the primaries, TESS archive, and literature data.Methods. These WDs are easy targets for SPHERE and were used as spectrophotometric standards. We performed very accurate abundance analyses for the MS stars using methods considered for solar analogs. Whenever possible, WD parameters and orbits were obtained using Monte Carlo Markov chain methods.Results. We found brighter J and K magnitudes for HD 114174B than obtained previously and extended the photometry down to 0.95 mu m. Our new data indicate a higher temperature and then shorter cooling age (5.570.02 Gyr) and larger mass (0.75 +/- 0.03 M-circle dot) for this WD than previously assumed. Together with the oldest age for the MS star connected to the use of the Gaia DR2 distance, this solved the discrepancy previously found with the age of the MS star. The two other WDs are less massive, indicating progenitors of similar to 1.3 M-circle dot and 1.5-1.8 M-circle dot for HD 2133B and CD-56 7708B, respectively. In spite of the rather long periods, we were able to derive useful constraints on the orbit for HD 114174 and CD-56 7708. They are both seen close to edge-on, which is in agreement with the inclination of the MS stars that are obtained coupling the rotational periods, stellar radii, and the projected rotational velocity from spectroscopy. The composition of the MS stars agrees fairly well with expectations from pollution by the AGB progenitors of the WDs: HD 2133A has a small enrichment of n-capture elements, which is as expected for pollution by an AGB star with an initial mass < 1.5 M-<circle dot>; CD-56 7708A is a previously unrecognized mild Ba-star, which is also expected due to pollution by an AGB star with an initial mass in the range of 1.5-3.0 M-circle dot; and HD 114174 has a very moderate excess of n-capture elements, which is in agreement with the expectation for a massive AGB star to have an initial mass > 3.0 M-circle dot.Conclusions. On the other hand, none of these stars show the excesses of C that are expected to go along with those of n-capture elements. This might be related to the fact that these stars are at the edges of the mass range where we expect nucleosynthesis related to thermal pulses. More work, both theoretical and observational, is required to better understand this issue. (AU)

• FAPESP's process: 18/04055-8 - High precision spectroscopy: from the first stars to planets
• Grantee: Jorge Luis Melendez Moreno
• Support Opportunities: Research Projects - Thematic Grants