J/A+A/402/963 Stephenson Hα stars (Maheswar+, 2003)
Optical spectroscopic and 2MASS measurements of Stephenson Hα stars.
Maheswar G., Manoj P., Bhatt H.C.
<Astron. Astrophys. 402, 963 (2003)>
=2003A&A...402..963M 2003A&A...402..963M
ADC_Keywords: Stars, pre-main sequence ; Stars, emission ; Photometry, CCD ;
Photometry, infrared
Keywords: stars: emission-line, Be - stars: general - stars: pre-main sequence -
stars: late-type - infrared: stars
Abstract:
We present the results of spectroscopic observations for 52 objects
from the list of Hα emission stars of Stephenson
(1986ApJ...300..779S 1986ApJ...300..779S). Out of six known T Tauri stars observed, five
showed Hα in emission and in one (StHa 40), Hα changed
from being in absorption to emission over a period of two years,
accompanied by photometric and spectral type variability. We confirm
the T Tauri nature of one Stephenson object (StHa 48) on the basis of
the presence of Hα and Hβ in emission, Li I λ6708 in
absorption, infrared excess and X-ray emission. Among the 52 objects
observed, there were other emission line objects: 1 Ke star, 1 BQ[]
star, 2 galaxies and 2 Be stars. We present a higher-resolution
spectrum of StHa 62 showing permitted and forbidden lines in emission
typical of BQ[] stars. Twenty five out of 30 newly observed objects
failed to show Hα in emission. We also present 2MASS
observations for 112 StHa objects. We suggest three Stephenson objects
(StHa 52, 125 and 129) to be YSOs on the basis of 2MASS, IRAS and
ROSAT observations. These and all other known YSOs amongst StHa stars
are found in regions of star-forming clouds in Taurus, Orion and
Ophiuchus. YSOs at high galactic latitudes in other parts of the sky
are therefore rare.
Description:
Optical CCD spectra of StHa stars were obtained using the OMR
(Optomechanics Research) spectrograph (Prabhu et al., 1998, Bulletin
of the Astronomical Society of India, 26, 383) on the 2:34m VBT at
Vainu Bappu Observatory during the period 1999-2002. StHa 57 was
observed on 3 January 2003.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 109 146 2MASS, IRAS and ROSAT results of Stephenson
stars object
table2.tex 159 215 LaTeX version of table2
refs.dat 92 18 References
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See also:
J/ApJ/300/779 : High-latitude H-alpha emission stars (Stephenson+, 1986)
V/73 : Emission-Line Stars of the Orion Population (Herbig+ 1988)
V/110 : Catalog of Cataclysmic Variables (Downes+ 2001)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [StHa]
6- 8 I3 --- StHa StHa number (Stepheson, 1986ApJ...300..779S 1986ApJ...300..779S)
10- 14 F5.3 arcmin r ? Distance StHa star to the 2MASS detection
16- 21 F6.3 mag Jmag ? J magnitude
23- 26 F4.2 mag e_Jmag ? rms uncertainty on Jmag
28- 33 F6.3 mag Hmag ? H magnitude
35- 38 F4.2 mag e_Hmag ? rms uncertainty on Hmag
40- 44 F5.2 mag Ksmag ? Ks magnitude
46- 49 F4.2 mag e_Ksmag ? rms uncertainty on Ksmag
51- 55 F5.2 mag J-H ? J-H colour index
57- 61 F5.2 mag H-Ks ? H-Ks colour index
63- 70 A8 --- SpType Spectral Type
72- 73 I2 --- r_SpType ? References for spectral type,
in refs.dat file
76- 80 F5.3 arcmin DistIRAS ? Radial distance of IRAS detection
82- 86 F5.3 arcmin DistROSAT ? Radial distance of ROSAT detection
88-102 A15 --- Class Class of object
103-104 A2 --- n_Class [*+d ] Note on Class (1)
107-108 I2 --- r_Class ? Reference for Class, in refs.dat file
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Note (1): Notes on Class:
*: Stars that are in common with those of Downes & Keyes
(1988AJ.....96..777D 1988AJ.....96..777D).
+: semi-regular pulsating variable star
d: Planetary nebula
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 51 A28 --- Aut Author's name
56- 92 A37 --- Com Comments
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Acknowledgements: Maheswar Gopinathan
(End) Patricia Bauer [CDS] 29-Apr-2003