Isochronal age-mass discrepancy of young stars: SCExAO/CHARIS integral field spectroscopy of the HIP 79124 triple system
Brandt, Timothy D.
AffiliationUniv Arizona, Steward Observ
stars: pre-main sequence
techniques: imaging spectroscopy
planets and satellites: detection
MetadataShow full item record
PublisherEDP SCIENCES S A
CitationAsensio-Torres, R., Currie, T., Janson, M., Desidera, S., Kuzuhara, M., Hodapp, K., ... & Kasdin, J. (2019). Isochronal age-mass discrepancy of young stars: SCExAO/CHARIS integral field spectroscopy of the HIP 79124 triple system. Astronomy & Astrophysics, 622, A42.
JournalASTRONOMY & ASTROPHYSICS
Rights© ESO 2019
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWe present SCExAO/CHARIS 1.1-2.4 mu m 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 similar to 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 similar to 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 (similar to 3 Myr) than for the primary star (similar to 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.
NoteOpen access journal.
VersionFinal published version
SponsorsKnut and Alice Wallenberg foundation; "Progetti Premiali" funding scheme of the Italian Ministry of Education, University, and Research; MEXT/JSPS KAKENHI [17K05399, 18H05442, 15H02063, 22000005]; Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan [2302, 23103002]