Skip navigation
  • INAF logo
  • Home
  • Communities
    & Collections
  • Research outputs
  • Researchers
  • Organization units
  • Projects
  • Explore by
    • Research outputs
    • Researchers
    • Organization units
    • Projects
  • Login:
    • My DSpace
    • Receive email
      updates
    • Edit Account details
  • Italian
  • English

  1. OA@INAF
  2. PRODOTTI RICERCA INAF
  3. 1 CONTRIBUTI IN RIVISTE (Journal articles)
  4. 1.01 Articoli in rivista
Please use this identifier to cite or link to this item: http://hdl.handle.net/20.500.12386/27181
Title: X-shooter spectroscopy of young stellar objects in Lupus. Atmospheric parameters, membership, and activity diagnostics
Authors: FRASCA, Antonio 
BIAZZO, Katia 
ALCALA', JUAN MANUEL 
Manara, C. F.
STELZER, BEATE 
COVINO, Elvira 
ANTONIUCCI, Simone 
Issue Date: 2017
Journal: ASTRONOMY & ASTROPHYSICS 
Number: 602
First Page: A33
Abstract: Aims: A homogeneous determination of basic stellar parameters of young stellar object (YSO) candidates is needed to confirm their pre-main sequence evolutionary stage and membership to star forming regions (SFRs), and to get reliable values of the quantities related to chromospheric activity and accretion. <BR /> Methods: We used the code ROTFIT and synthetic BT-Settl spectra for the determination of the atmospheric parameters (T<SUB>eff</SUB> and log g), veiling (r), radial (RV), and projected rotational velocity (vsini) from X-shooter spectra of 102 YSO candidates (95 of infrared Class II and seven Class III) in the Lupus SFR. The spectral subtraction of inactive templates, rotationally broadened to match the vsini of the targets, enabled us to measure the line fluxes for several diagnostics of both chromospheric activity and accretion, such as Hα, Hβ, Ca II, and Na I lines. <BR /> Results: We have shown that 13 candidates can be rejected as Lupus members based on their discrepant RV with respect to Lupus and/or the very low log g values. At least 11 of them are background giants, two of which turned out to be lithium-rich giants. Regarding the members, we found that all Class III sources have Hα fluxes that are compatible with a pure chromospheric activity, while objects with disks lie mostly above the boundary between chromospheres and accretion. Young stellar objects with transitional disks display both high and low Hα fluxes. We found that the line fluxes per unit surface are tightly correlated with the accretion luminosity (L<SUB>acc</SUB>) derived from the Balmer continuum excess. This rules out that the relationships between L<SUB>acc</SUB> and line luminosities found in previous works are simply due to calibration effects. We also found that the Ca II-IRT flux ratio, F<SUB>CaII8542</SUB>/F<SUB>CaII8498</SUB>, is always small, indicating an optically thick emission source. The latter can be identified with the accretion shock near the stellar photosphere. The Balmer decrement reaches instead, for several accretors, high values typical of optically thin emission, suggesting that the Balmer emission originates in different parts of the accretion funnels with a smaller optical depth. <P />Based on observations collected at the Very Large Telescope of the European Southern Observatory at Paranal, under programs 084.C-0269(A), 085.C-0238(A), 086.C-0173(A), 087.C-0244(A), 089.C-0143(A), 095.C-0134(A), 097.C-0349(A), and archive data of programmes 085.C-0764(A) and 093.C-0506(A). Tables 1-3 are also available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/602/A33">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/602/A33</A>
URI: http://hdl.handle.net/20.500.12386/27181
URL: https://www.aanda.org/articles/aa/full_html/2017/06/aa30108-16/aa30108-16.html
ISSN: 0004-6361
DOI: 10.1051/0004-6361/201630108
Bibcode ADS: 2017A&A...602A..33F
Fulltext: open
Appears in Collections:1.01 Articoli in rivista

Files in This Item:
File Description SizeFormat 
aa30108-16.pdfpdf editoriale1.99 MBAdobe PDFView/Open
Show full item record

Page view(s)

15
checked on Feb 24, 2021

Download(s)

2
checked on Feb 24, 2021

Google ScholarTM

Check

Altmetric


Items in DSpace are published in Open Access, unless otherwise indicated.


Explore by
  • Communities
    & Collections
  • Research outputs
  • Researchers
  • Organization units
  • Projects

Informazioni e guide per autori

https://openaccess-info.inaf.it: tutte le informazioni sull'accesso aperto in INAF

Come si inserisce un prodotto: le guide a OA@INAF

La Policy INAF sull'accesso aperto

Documenti e modelli scaricabili

Feedback
Built with DSpace-CRIS - Extension maintained and optimized by Logo 4SCIENCE