2008A&A...491..311S


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.17CET20:02:36

2008A&A...491..311S - Astronomy and Astrophysics, volume 491, 311-320 (2008/11-3)

Direct evidence of a sub-stellar companion around CT Chamaeleontis.

SCHMIDT T.O.B., NEUHAEUSER R., SEIFAHRT A., VOGT N., BEDALOV A., HELLING Ch., WITTE S. and HAUSCHILDT P.H.

Abstract (from CDS):

In our ongoing search for close and faint companions around T Tauri stars in the Chamaeleon star-forming region, we here present observations of a new common proper motion companion to the young T-Tauri star and Chamaeleon member CT Cha and discuss its properties in comparison to other young, low-mass objects and to synthetic model spectra from different origins. Common proper motion of the companion and CT Cha was confirmed by direct Ks-band imaging data taken with the VLT Adaptive Optics (AO) instrument NACO in February 2006 and March 2007, together with a Hipparcos binary for astrometric calibration. An additional J-band image was taken in March 2007 to obtain color information for a first classification of the companion. Moreover, AO integral field spectroscopy with SINFONI in J, and H+K bands was obtained to deduce physical parameters of the companion, such as temperature and extinction. Relative flux calibration of the bands was achieved using photometry from the NACO imaging data. We found a very faint (Ks=14.9mag, Ks0=14.4mag) object, just ∼2.67" northwest of CT Cha corresponding to a projected separation of ∼440AU at 165±30pc. We show that CT Cha A and this faint object form a common proper motion pair and that the companion is by ≥4σ significance not a stationary background object. The near-infrared spectroscopy yields a temperature of 2600±250K for the companion and an optical extinction of AV=5.2±0.8mag, when compared to spectra calculated from Drift-Phoenix model atmospheres. We demonstrate the validity of the model fits by comparison to several other well-known young sub-stellar objects. We conclude that the CT Cha companion is a very low-mass member of Chamaeleon and very likely a physical companion to CT Cha, as the probability for a by chance alignment is ≤0.01. Due to a prominent Pa-β emission in the J-band, accretion is probably still ongoing onto the CT Cha companion. From temperature and luminosity (log(Lbol/L)=-2.68±0.21), we derive a radius of R=2.20–0.60+0.81RJup. We find a consistent mass of M=17±6MJup for the CT Cha companion from both its luminosity and temperature when placed on evolutionary tracks. Hence, the CT Cha companion is most likely a wide brown dwarf companion or possibly even a planetary mass object.

Abstract Copyright:

Journal keyword(s): stars: pre-main sequence - stars: planetary systems: formation - stars: individual: CT Cha

Simbad objects: 20

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Number of rows : 20

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 * 54 Psc B BD* 00 39 18.91 +21 15 16.8           T7.5 61 1
2 2MASS J01415823-4633574 BD* 01 41 58.2345784233 -46 33 57.347491326           L2 62 0
3 V* V2384 Ori Al* 05 35 21.8463185314 -05 46 08.560286991       19.21 17.28 M7 86 1
4 HD 42581B BD* 06 10 34.80 -21 52 00.0           T6.5 450 0
5 NAME CT Cha b BD? 11 04 08.44 -76 27 18.0           M8 36 1
6 V* CT Cha Or* 11 04 09.0989057683 -76 27 19.326914289   13.44 13.00   10.89 K7Ve 107 1
7 HD 96675 pr* 11 05 57.8104415475 -76 07 48.883424761   7.82 7.68   8.48 B6IV/V 68 0
8 CHXR 73B Pl 11 06 28.7626436677 -77 37 33.144403799           ~ 29 1
9 CHXR 73 Y*O 11 06 28.7626436677 -77 37 33.144403799         15.78 M3e 42 1
10 NAME Cha I MoC 11 06 48 -77 18.0           ~ 946 1
11 NAME Cha Dark Cloud SFR 11 55 -78.0           ~ 537 1
12 NAME Chamaeleon Region SFR 12 00 -79.0           ~ 169 1
13 2MASS J12043036+3212595 BD* 12 04 30.3586594618 +32 12 59.518262384           L0e 15 0
14 HD 132347 ** 14 59 29.23211 -30 42 41.5076           A3mA5-F0 21 0
15 HD 137013 PM* 15 24 47.8170954141 -32 08 29.789217344   9.39 8.73     G3V 9 0
16 CD-35 10525 TT* 15 49 12.102 -35 39 05.12 12.19 12.36 11.40     K7Ve 233 0
17 2MASS J16064818-2230400 BD* 16 06 48.1809367086 -22 30 40.025451345           M8.00 13 0
18 2MASS J16071478-2321011 BD* 16 07 14.78 -23 21 01.1           L0 18 0
19 NAME Upper Sco Association As* 16 12 -23.4           ~ 975 1
20 * eps Ind B BD* 22 04 10.52 -56 46 57.7     24.12 20.8 15.60 T1V+T6V 123 2

    Equat.    Gal    SGal    Ecl

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2020.02.17-20:02:36

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