2014A&A...567A..30M


C.D.S. - SIMBAD4 rel 1.7 - 2019.08.26CEST10:18:45

2014A&A...567A..30M - Astronomy and Astrophysics, volume 567A, 30-30 (2014/7-1)

IP Eridani: A surprising long-period binary system hosting a He white dwarf.

MERLE T., JORISSEN A., MASSERON T., VAN ECK S., SIESS L. and VAN WINCKEL H.

Abstract (from CDS):

We determine the orbital elements for the K0 IV + white dwarf (WD) system IP Eri, which appears to have a surprisingly long period of 1071d and a significant eccentricity of 0.25. Previous spectroscopic analyses of the WD, based on a distance of 101pc inferred from its Hipparcos parallax, yielded a mass of only 0.43M, implying it to be a helium-core WD. The orbital properties of IP Eri are similar to those of the newly discovered long-period subdwarf B star (sdB) binaries, which involve stars with He-burning cores surrounded by extremely thin H envelopes, and are therefore close relatives to He WDs. We performed a spectroscopic analysis of high-resolution spectra from the HERMES/Mercator spectrograph and concluded that the atmospheric parameters of the K0 component are Teff=4960K, logg=3.3, [Fe/H]=0.09 and ξ=1.5km/s. The detailed abundance analysis focuses on C, N, O abundances, carbon isotopic ratio, light (Na, Mg, Al, Si, Ca, Ti) and s-process (Sr, Y, Zr, Ba, La, Ce, Nd) elements. We conclude that IP Eri abundances agree with those of normal field stars of the same metallicity. The long period and non-null eccentricity indicate that this system cannot be the end product of a common-envelope phase; it calls instead for another less catastrophic binary-evolution channel presented in detail in a companion paper.

Abstract Copyright:

Journal keyword(s): stars: abundances - binaries: spectroscopic - stars: evolution - stars: individual: IP Eridani - subdwarfs - white dwarfs

VizieR on-line data: <Available at CDS (J/A+A/567/A30): list.dat sp/*>

Simbad objects: 2

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Number of rows : 2

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 HD 18131 BY* 02 54 38.8239618040 -05 19 50.930526115   8.32 7.31     K0IV+DA: 55 0
2 * 63 Eri SB* 04 59 50.4609687587 -10 15 47.820334404   6.180 5.390     G4IV-V+DA 93 1

    Equat.    Gal    SGal    Ecl

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2019.08.26-10:18:45

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