TY - JOUR
T1 - Isochronal age-mass discrepancy of young stars
T2 - SCExAO/CHARIS integral field spectroscopy of the HIP 79124 triple system
AU - Asensio-Torres, Ruben
AU - Currie, Thayne
AU - Janson, Markus
AU - Desidera, Silvano
AU - Kuzuhara, Masayuki
AU - Hodapp, Klaus
AU - Brandt, Timothy D.
AU - Guyon, Olivier
AU - Lozi, Julien
AU - Groff, Tyler
AU - Kasdin, Jeremy
AU - Chilcote, Jeffrey
AU - Jovanovic, Nemanja
AU - Martinache, Frantz
AU - Sitko, Michael
AU - Serabyn, Eugene
AU - Wagner, Kevin
AU - Akiyama, Eiji
AU - Kwon, Jungmi
AU - Uyama, Taichi
AU - Yang, Yi
AU - Nakagawa, Takao
AU - Hayashi, Masahiko
AU - McElwain, Michael
AU - Kudo, Tomoyuki
AU - Henning, Thomas
AU - Tamura, Motohide
N1 - Funding Information:
R.A.-T. and M.J. gratefully acknowledge funding from the Knut and Alice Wallenberg foundation. S.D. acknowledges support from the Progetti Premiali funding scheme of the Italian Ministry of Education, University, and Research. E. A. is supported by MEXT/JSPS KAKENHI grant No. 17K05399. M.T. is supported by MEXT/JSPS KAKENHI grant Nos. 18H05442, 15H02063, and 22000005.M. H. is supported by the Grant-in-Aid for Scientific Research on Innovative Areas (2302, 23103002) under the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan
Publisher Copyright:
© ESO 2019.
PY - 2019/2/1
Y1 - 2019/2/1
N2 - We present SCExAO/CHARIS 1.1-2.4 μm integral field direct spectroscopy of the young HIP 79124 triple system. HIP 79124 is a member of the Scorpius-Centaurus association, consisting of an A0V primary with two low-mass companions at a projected separation of < 1″. Thanks to the high quality wavefront corrections provided by SCExAO, both companions are decisively detected without the employment of any PSF-subtraction algorithm to eliminate quasi-static noise. The spectrum of the outer C object is very well matched by Upper Scorpius M4 ± 0.5 standard spectra, with a T eff = 2945 ± 100 K and a mass of ∼350 M Jup . HIP 79124 B is detected at a separation of only 180 mas in a highly-correlated noise regime, and it falls in the spectral range M6 ± 0.5 with T eff = 2840 ± 190 K and ∼100 M Jup . Previous studies of stellar populations in Sco-Cen have highlighted a discrepancy in isochronal ages between the lower-mass and higher-mass populations. This could be explained either by an age spread in the region, or by conventional isochronal models failing to reproduce the evolution of low-mass stars. The HIP 79124 system should be coeval, and therefore it provides an ideal laboratory to test these scenarios. We place the three components in a color-magnitude diagram and find that the models predict a younger age for the two low-mass companions (∼3 Myr) than for the primary star (∼6 Myr). These results imply that the omission of magnetic effects in conventional isochronal models inhibit them from reproducing early low-mass stellar evolution, which is further supported by the fact that new models that include such effects provide more consistent ages in the HIP 79124 system.
AB - We present SCExAO/CHARIS 1.1-2.4 μm integral field direct spectroscopy of the young HIP 79124 triple system. HIP 79124 is a member of the Scorpius-Centaurus association, consisting of an A0V primary with two low-mass companions at a projected separation of < 1″. Thanks to the high quality wavefront corrections provided by SCExAO, both companions are decisively detected without the employment of any PSF-subtraction algorithm to eliminate quasi-static noise. The spectrum of the outer C object is very well matched by Upper Scorpius M4 ± 0.5 standard spectra, with a T eff = 2945 ± 100 K and a mass of ∼350 M Jup . HIP 79124 B is detected at a separation of only 180 mas in a highly-correlated noise regime, and it falls in the spectral range M6 ± 0.5 with T eff = 2840 ± 190 K and ∼100 M Jup . Previous studies of stellar populations in Sco-Cen have highlighted a discrepancy in isochronal ages between the lower-mass and higher-mass populations. This could be explained either by an age spread in the region, or by conventional isochronal models failing to reproduce the evolution of low-mass stars. The HIP 79124 system should be coeval, and therefore it provides an ideal laboratory to test these scenarios. We place the three components in a color-magnitude diagram and find that the models predict a younger age for the two low-mass companions (∼3 Myr) than for the primary star (∼6 Myr). These results imply that the omission of magnetic effects in conventional isochronal models inhibit them from reproducing early low-mass stellar evolution, which is further supported by the fact that new models that include such effects provide more consistent ages in the HIP 79124 system.
KW - Binaries: close
KW - Planets and satellites: detection
KW - Stars: low-mass
KW - Stars: pre-main sequence
KW - Techniques: imaging spectroscopy
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U2 - 10.1051/0004-6361/201834688
DO - 10.1051/0004-6361/201834688
M3 - Article
AN - SCOPUS:85060887361
SN - 0004-6361
VL - 622
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A42
ER -