1994A&A...288..165A


Query : 1994A&A...288..165A

1994A&A...288..165A - Astronomy and Astrophysics, volume 288, 165-174 (1994/8-1)

Is ESO Hα 279 a pre-main sequence binary ?

ASPIN C., REIPURTH B. and LEHMANN T.

Abstract (from CDS):

We present 1-3.4µm near-IR array images of ESO Hα 279, the optical emission line star proposed to be the exciting source of the bipolar Herbig-Haro complex HH106/107 in Serpens. These images show the presence of a close, bright infrared stellar companion to ESO Hα 279 located 8.2" due south. At 2µm, no other sources are seen within ∼1' of these stars suggesting that ESO Hα 279 and its companion may form a pre-main sequence (PMS) binary. Our NIR photometry has shown that the optical emission line star, ESO Hα 279a, is a young, PMS object possessing a strong thermal excess beyond 2µm. Additionally, 2µm spectroscopy has revealed that ESO Hα 279a possesses very strong CO bandhead emission from 2.29-2.45µm indicative of the presence of an active accretion disk and/or molecular outflow. The companion source, ESO Hα 279b, was found to be extremely red with a J-K∼7. Spectroscopy showed that it possesses strong CO bandhead absorption. From both the relative strengths of the dereddened spectral features and evidence provided by the near-IR photometry, we suggest that ESO Hα 279b is likely not a PMS companion to ESO Hα 279a, but rather it is a highly reddened (AV=30-40) background M5 III giant. This result emphasizes the extreme care that needs to be taken when using infrared imaging data to study the frequency of binaries amongst PMS stars.

Abstract Copyright:

Journal keyword(s): stars: pre-main sequence - circumstellar matter - formation - binaries: general, ESO Hα 279 (ESO-HA 279) - ISM: individual: Serpens cloud

Nomenclature: ESO-HA NNNa (Nos 279a, 279b) added.

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* DG Tau Or* 04 27 04.6913654419 +26 06 16.041555299 13.57 13.97 10.50 12.28   K6Ve 967 1
2 EM* LkHA 336 TT* 05 54 20.0901956844 +01 42 56.565144134   15.78 14.0     K5e 23 2
3 [RP93] 6 Em* 07 31 37.4226205927 -47 00 21.615938928   15.84 14.19 13.21 12.12 K7 5 1
4 V* VW Cha Or* 11 08 01.3974165580 -77 42 28.579297348 13.91 14.04 12.80   10.69 K7+M0 170 0
5 HH 106 HH 18 29 18.8 +01 14 17           ~ 15 0
6 ESO-HA 279b Y*O 18 29 31.934 +01 18 34.36           ~ 4 1
7 ESO-HA 279a cor 18 29 31.976 +01 18 42.59           K6.5 29 1
8 HH 107 HH 18 29 48.0 +01 25 55           ~ 10 0

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2021.10.20-18:26:47

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