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 - 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
UR - http://www.scopus.com/inward/record.url?scp=85060887361&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85060887361&partnerID=8YFLogxK
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 -