A PAN-STARRS plus UKIDSS SEARCH FOR YOUNG, WIDE PLANETARY-MASS COMPANIONS IN UPPER SCORPIUS

被引：47

作者：

Aller, Kimberly M. ^{[1
]}

Kraus, Adam L. ^{[1
,2
]}

Liu, Michael C. ^{[1
]}

Burgett, William S. ^{[1
]}

Chambers, Kenneth C. ^{[1
]}

Hodapp, Klaus W. ^{[1
]}

Kaiser, Nick ^{[1
]}

Magnier, Eugene A. ^{[1
]}

Price, Paul A. ^{[3
]}

机构：

[1] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA

[2] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[3] Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA

来源：

ASTROPHYSICAL JOURNAL | 2013年 / 773卷 / 01期

基金：

美国国家科学基金会;

关键词：

binaries: general; brown dwarfs; planetary systems; stars: pre-main sequence; BROWN DWARF CANDIDATES; NEAR-INFRARED SPECTRA; SOLAR-TYPE STARS; SKY SURVEY 2MASS; OB ASSOCIATION; HR; 8799; GRAVITATIONAL-INSTABILITY; SUBSTELLAR COMPANION; CIRCUMSTELLAR DISKS; EVOLUTIONARY MODELS;

D O I：

10.1088/0004-637X/773/1/63

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We have combined optical and NIR photometry from Pan-STARRS 1 and UKIDSS to search the young (5-10 Myr) star-forming region of Upper Scorpius for wide (approximate to 400-4000 AU) substellar companions down to similar to 5M(Jup). Our search is approximate to 4 mag deeper than previous work based on the Two Micron All Sky Survey. We identified several candidates around known stellar members using a combination of color selection and spectral energy distribution fitting. Our follow-up spectroscopy has identified two new companions as well as confirmed two companions previously identified from photometry, with spectral types of M7.5-M9 and masses of similar to 15-60 M-Jup, indicating a frequency for such wide substellar companions of similar to 0.6% +/- 0.3%. Both USco 1610-1913B and USco 1612-1800B are more luminous than expected for their spectral type compared with known members of Upper Sco. HIP 77900B has an extreme mass ratio (M-2/M-1 approximate to 0.005) and an extreme separation of 3200 AU. USco 1602-2401B also has a very large separation of 1000 AU. We have also confirmed a low-mass stellar companion, USco 1610-2502B (730 AU, M5.5). Our substellar companions appear both non-coeval with their primary stars according to evolutionary models and, as a group, are systematically more luminous than the Upper Sco cluster sequence. One possible reason for these luminosity discrepancies could be different formation processes or accretion histories for these objects.

引用

页数：15

共 85 条

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