Two new T Tauri stars and a candidate FU Orionis star associated with Bok globules
|
|
- Abner Craig
- 5 years ago
- Views:
Transcription
1 Astron. Astrophys. 320, (1997) ASTRONOMY AND ASTROPHYSICS Two new T Tauri stars and a candidate FU Orionis star associated with Bok globules J.L. Yun 1, M.C. Moreira 1, J.F. Alves 1, and J. Storm 2 1 Departamento de Física, Universidade de Lisboa, Campo Grande, Edif. C1, 1700 Lisboa, Portugal 2 European Southern Observatory, Casilla 19001, Santiago, Chile Received 20 May 1996 / Accepted 25 September 1996 Abstract. We present photometric and spectroscopic evidence of two new T Tauri stars formed in the conditions of isolated small Bok globules. The spectral energy distributions of these objects display excess infrared emission, they are associated with optical reflection nebulae, and their optical spectra reveal Balmer emission lines and the Li I λ6707 Å absorption line. Additionnally, we report the discovery of what may be a new FU Orionis star seen towards Bok globule CB 34. The star is about 4 magnitudes brighter than it appears on the Palomar plates and is associated with the aggregate of young stellar objects forming in Bok globule CB 34. Key words: stars: formation stars: pre-main-sequence ISM: clouds ISM: individual: CB 34 infrared: stars 1. Introduction T Tauri stars were the first group of objects recognized as young pre-main sequence stars (Joy 1945). We now believe that classical T Tauri stars are young low-mass stars ( 2M ) surrounded by circumstellar accretion disks. Since the discovery of the first T Tauri stars, about 800 pre-main sequence stars have been optically identified and listed in the Herbig & Bell (1988) Catalog. T Tauri stars like other young stars tend to form in groups embedded in molecular clouds. Many are typically found in loose clusters known as T associations. Multiple star formation however does not facilitate the study of the star formation process. Observations of the formation of just one or a couple of stars can certainly provide a simpler laboratory for the study of the star formation process. Isolated T Tauri stars exist and are likely to form in the core of the smallest and simplest molecular clouds: the small Bok globules. The physical conditions in Bok globules are similar to those in dark cloud cores where lowmass star formation has been shown to take place (Myers et al. 1987). Moreover, given their small size and isolation (Clemens Send offprint requests to: J.L.Yun & Barvainis 1988), Bok globules are the ideal laboratories for studying the formation of single or a couple of low-mass stars. During the last years, it has been shown that low-mass star formation is a rather common phenomenon in Bok globules (e.g. Yun & Clemens 1990; 1994a), displaying all ordinary signposts of active star formation, such as the presence of high-velocity molecular outflows, (Yun & Clemens 1992, 1994b), optical and/or near-infrared jets (Moreira & Yun 1995), infrared reflection nebulae (Yun et al ; Yun & Clemens 1994a), and infrared binary protostars (Yun 1996). Both Class I and Class II objects (Adams, Lada, & Shu 1987) have been found to have formed in Bok globules (Yun & Clemens 1995). Class II objects are thought to be T Tauri stars with their infrared excess emission due to the presence of circumstellar disks. Their T Tauri nature can only be definitely confirmed spectroscopically. In fact, classical T Tauri stars are emission line objects, with prominent Balmer lines and frequently displaying the Li I line (λ6707 Å, in absorption) typical of young stars. Another class of phenomena that is thought to be closely related to the star formation process is named FU Orionis phenomenon. A FU Orionis (FUor) object typically undergoes a rapid increase in its optical brightness that may reach 5 magnitudes in less than a year (Herbig 1966, 1977, 1989; Reipurth 1990). Paczynski (1976) and Hartmann & Kenyon (1985) have attributed these outbursts to large (up to three orders of magnitude) increases in the accretion rate on a central T Tauri star, probably due to instabilities ocurring in a massive circumstellar disk. The FUor stage could be a short-lived but important aspect of the star formation process significantly affecting the evolution of a star. Few FUor objects are known (e.g. Hartmann et al. 1993; Strom & Strom 1993; Evans et al. 1994). All are associated with reflection nebulae and large infrared excesses (e.g. Goodrich 1987) indicating they are pre-main sequence objects. In addition, they seem to display distinctive spectroscopic properties: G-type supergiant optical spectra; broad absorption lines, deep, blue-shifted absorption components on Hα and Na I D; CO absorption bands (e.g. Hartmann et al. 1993). However, it has been noted (Herbig 1989) that the spectra of FUors may not
2 168 J.L. Yun et al.: Two new T Tauri stars and a candidate FU Orionis star associated with Bok globules Fig. 1. V-band CCD image of CB31YC1. The new T Tauri star, CB31YC1, is the bright star at the center of the image. Notice the associated optical nebulosity. necessarily point to the existence of a self-luminous accretion disk. Instead, the spectra may alternatively be interpreted as indicating a peculiar, rapidly-rotating star with a semi-transparent atmosphere plus circumstellar material. During our survey of T Tauri stars in Bok globules, we confirmed the T Tauri nature of a subset of our Class II sources. In addition, we found an object that is likely to be a new FU Ori star. In this paper, we report these findings. In Sect. 2 we describe observations and data reduction. In Sect. 3 we present and discuss our results, and in Sect. 4 we summarize our conclusions. Fig. 2. Top: Broad-band spectral energy distribution of CB31YC1. Filled circles correspond to flux values, open circles represent upper limits (in the IRAS PSC catalog). The dotted line represents a blackbody (T = 3700 K) fit to the V-band flux and is shown for comparison purposes only. Bottom: Optical spectra of CB31YC1. Notice the presence of the Hα emission line as well as the Li I absorption line. 2. Observations and data reduction Optical imaging observations towards Class II YSOs in Bok globules (Yun & Clemens 1995) were carried out during the nights of 1993 December using the European Southern Observatory 0.9 m Dutch telescope equipped with a pixel CCD detector. Images were obtained using a set of filters which included broad-band B, V, R, I filters. The detector was used at a plate scale of 0.46 arcsec per pixel, resulting in a field of view of arcmin 2 on the sky. In addition, in 1994 December and 1995 December, we obtained medium resolution ( 7Å per pixel) optical spectra and additional R-band images, using the ESO Danish 1.54 m telescope equipped with the Danish Faint Object Spectrograph and Camera (DFOSC) detector. Calibration lamps (He and Ne) were observed immediately before or after each object spectrum. Near-infrared observations were made in 1993 December 20 using the IRAC2 NICMOS 3 infrared array camera mounted on the ESO 2.2 m telescope. We obtained a set of 9 dithered frames in the JHK-bands, with a total integration time per frame of 30 seconds. Standard CCD image reduction procedures (dark and bias subtraction, and flat-fielding) were applied to the optical CCD images, using the NOAO Image Reduction and Analysis Facility (IRAF 1 ). Similarly, standard IRAF packages were used to make the spectroscopic reductions (SPECRED). Reduction of the near-infrared images were performed by subtraction of a sky frame (computed by median filtering of 1 IRAF is distributed by National Optical Astronomy Observatories which are operated by the Association of Universities for Research in Astronomy, Inc., under contract to the National Science Foundation.
3 J.L. Yun et al.: Two new T Tauri stars and a candidate FU Orionis star associated with Bok globules 169 Table 1. Object coordinates and photometry CB31YC1 CB32 T Tauri CB 34 FU R. A. (1950) 5 h 30 m 45 s 5 h 33 m 57 s 5 h 44 m 04.5 s Dec. (1950) B V R I J H K the 9 dithered images) followed by flat-fielding. The final flatfielded images were subsequently corrected for the presence of bad pixels and mosaicked, co-adding the overlapping regions. 3. Results and discussion 3.1. Two new T Tauri stars CB31YC1 CB31YC1 is a relatively bright and isolated optical visible star located to the northwest of the center of Bok globule CB31. It is associated with tenuous optical nebular emission (Fig 1). Photometry of this object was performed and transformed to the Johnson standard system. Magnitudes in the B, V, R, I, J, H, and K bands are given in Table 1. CB31YC1 was classified as a Class II source by Yun & Clemens (1995). Its broad-band spectral energy distribution is shown in Fig. 2 (top), where the dotted line represents a blackbody fit to the V-band flux and is shown for comparison purposes only. The blackbody temperature was determined from the color index (B V ) (Carney et al. 1987). Given the good spatial coincidence with IRAS , and the absence of other candidates, this source was considered as being the optical counterpart of this IRAS source. Thus, the broad-band spectral energy distribution shown includes data points from 0.4µm to 100 µm. There is clearly excess infrared emission above that of a stellar photosphere (blackbody). The spectrum of CB31YC1 reveals the presence of Balmer lines (Hα and Hβ) in emission. Fig. 2 (bottom) shows part of the spectrum. The equivalent width of the Hα emission is 25 Å. The Li I (λ6707 Å) absorption line is also clearly present. Since the simultaneous presence of Hα emission and Li I (λ6707 Å) is a good spectroscopic criterium to decide on the T Tauri nature of a star, we conclude that CB31YC1 is a bona fide classical T Tauri star CB32 T Tauri The YSO candidate CB32YC1 whose spectral energy distribution was presented in Yun & Clemens (1995) was not included in this study. Instead, a nearby star associated with optical nebulosity was observed and its spectra obtained. We refer to this star Fig. 3. Top: V-band CCD image of CB32 T Tauri. This new T Tauri star is the bright star at the lower center of the image. Notice the associated optical nebulosity. Bottom: Optical spectrum of CB32 T Tauri. The Hα emission line is clearly present together with the Li I absorption line. as CB32 T Tauri. Fig. 3 (top) shows this star in a V-band CCD image of Bok globule CB32. CB32 T Tauri is the bright star at the lower center of the image. Coordinates and infrared magnitudes are given in Table 1. This star has no IRAS PSC counterpart and could not be discovered in IRAS-based searches. Its spectrum is presented in Fig 3 (bottom). Hα emission is seen (equivalent width = 3.6 Å) as well as the Li I absorption line. We conclude that this star is a weak-line T Tauri star. Being relatively bright (we estimate its Johnson V-band magnitude to be about 12), CB32 T Tauri could be an interesting object in which to study the wealth of photospheric phenomena usually associated with T Tauri stars.
4 170 J.L. Yun et al.: Two new T Tauri stars and a candidate FU Orionis star associated with Bok globules Fig. 5. Broad-band spectral energy distribution of the FUor candidate. The dotted line represents a blackbody (T = 3600 K) fit to the V-band flux and is shown for comparison purposes only A New Candidate FU Ori Star Fig. 4. Top: POSS image covering 4 arcmin 2 of Bok globule CB 34 including the new FUor candidate. Note carefully the triplet of three stars very close to one another. Middle: R-band CCD image of the same region obtained in 1993; Bottom: R-band CCD image of the same region obtained in Notice that the southwestern component of the stellar triplet has strongly increased its brightness. It also displays a small fan-shaped nebula. Fig. 4 (top) presents a 2 2 image obtained from the Palomar Observatory Sky Survey (POSS E) via the Digital Sky Survey. Note carefully, at the center of the image, the three stars very close to one another. Fig. 4 (middle), obtained with a CCD and an R-band filter in December 1993, shows the same region. Comparison of the triplet of stars located at the centers of these two images reveals that the southwest star (FU Orionis candidate, here tentatively named CB 34 FU) has brightened considerably between the times when the two images were taken (1950 and 1994). Fig. 4 (bottom) obtained in December 1994 with a CCD and an R-band filter shows the same region and reveals that the FUor candidate has kept its higher brightness for at least a year. Photometry of the stars present in the R-band CCD image together with a careful comparison of the brightness of CB 34 FU and the brightness of a field star in the Palomar image, lead us to an estimate of about 4.0 magnitudes for the change in the R-band magnitude of CB 34 FU. In addition, differential photometry between CB 34 FU and a field star indicates a slight increase in brightness, of about 0.1 mag, from the 1993 R-band image to the corresponding 1994 image. Magnitudes of CB 34 FU corresponding to December 1993, in the B, V, R, I, J, H, and K band are given in Table 1. Other evidence in favour of this object being a young star is provided by the near infrared excess emission revealed in its spectral energy distribution shown in Fig. 5. In this figure, the blackbody curve is shown for comparison purposes only, revealing the infrared excess emission above that of a photosphere. In addition, the presence of nebulosity surrounding the Fu Ori candidate (Fig. 4), looks similar to the one around the star FU Ori itself (fan-shaped), though less extended. The low brightness of this object resulted in insufficient signal-to-noise ratio in its spectra (shown in Fig. 6).
5 J.L. Yun et al.: Two new T Tauri stars and a candidate FU Orionis star associated with Bok globules 171 CB 34 FU is a candidate FU Ori star that increased its visual brightness by about 4 mag from 1951 to the present time. Further work is needed to confirm its FUor nature. Acknowledgements. This work has been partially supported by a JNICT grant to J.L.Y. Support from JNICT to M.C.M. and J.F.A. in the form of scholarships is gratefully acknowledged. References Fig. 6. Optical spectra of the FUor candidate. No special features are evident possibly due to insuffcient signal-to-noise ratio. The sodium doublet is marked with an arrow. The expected positions of the Hα and Li I lines are also indicated. The sodium doublet is present in absorption (with an equivalent width of 2.9 Å) which is one of the characteristics of the FU Ori stars. However, the doublet is not broad or blue-shifted as is common with FUors. The Li I line appears to be present but at a S/N of only about 2σ. Also, a higher spectral resolution and a more extended spectral coverage into the blue are needed in order to spectral type this object. Thus, the spectra are not conclusive and spectroscopic confirmation will require obtaining new optical spectra of this object with both higher resolution and higher signal-to-noise ratio. Near-infrared spectra would also be useful to search for the 2.3 µm CO absorption bands predicted by the FUor disk models. Adams, F. C., Lada, C. J., & Shu, F. H. 1987, ApJ, 312, 788 Carney, B. W., Laird, J. B., Latham, D. W., & Kurucz, R. L. 1987, AJ, 94, 1066 Clemens, D. P., & Barvainis, R. 1988, ApJS, 68, 257 Evans II, N. J., Balkum, S., Levreault, R. M., Hartmann, L., & Kenyon, S ApJ, 424, 793 Goodrich, R. 1987, PASP, 99, 116 Hartmann, L, & Kenyon, S. J., 1985, ApJ, 299, 462 Hartmann, L, Kenyon, S. J., & Hartigan, P. 1993, in Protostars & Planets III, edited by E. H. Levy and J. Lunine (University of Arizona Press, Tucson), p. 497 Herbig, G. H. 1966, Vistas in Astronomy, 8, 10 Herbig, G. H. 1977, ApJ, 217, 693 Herbig, G. H., & Bell, K. R. 1988, Lick Obs. Bull. No Herbig, G. H. 1989, in ESO Workshop on Low-Mass Star Formation and Pre-Main Sequence Objects, ed. B. Reipurth (Garching:ESO), pp. 233 Joy, A. H. 1945, ApJ, 102, 168 Moreira, M. C., & Yun, J. L. 1995, ApJ, 454, 850 Myers, P. C., Fuller, G. A., Mathieu, R. D., Beichman, C. A., Benson, P. J., Schild, R. E., and Emerson, J. P. 1987, ApJ, 319, 340. Paczynski, B. 1976, QJRAS, 17, 31 Reipurth, B. 1990, in IAU Symp. 136, Flare Stars in Star Clusters, Associations, and the Solar Vicinity, ed. L. V. Mirzoyan, B. R. Peterson, & M. K. Tsvetkov (Dordrecht:Kluwer), 285 Strom, K. M., & Strom, S. E. 1993, ApJ, 412, L63 Yun, J. L., & Clemens, D. P. 1990, ApJ, 365, L73 Yun, J. L., & Clemens, D. P. 1992, ApJ, 385, L21 Yun, J. L., Clemens, D. P., McCaughrean, M., & Rieke, M. 1993, ApJ, 408, L101 Yun, J. L., & Clemens, D. P. 1994a, AJ, 108, 612 Yun, J. L., & Clemens, D. P. 1994b, ApJS, 92, 145 Yun, J. L., & Clemens, D. P. 1995, AJ, 109, 742 Yun, J. L. 1996, AJ, 111, Conclusions We confirm the T Tauri nature of two bright Class II young stellar objects in Bok globules CB31 and CB32. This article was processed by the author using Springer-Verlag LaT E X A&A style file L-AA version 3.
Near-Infrared Imaging Observations of the Orion A-W Star Forming Region
Chin. J. Astron. Astrophys. Vol. 2 (2002), No. 3, 260 265 ( http: /www.chjaa.org or http: /chjaa.bao.ac.cn ) Chinese Journal of Astronomy and Astrophysics Near-Infrared Imaging Observations of the Orion
More informationBV RI photometric sequences for nine selected dark globules
ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 126, 73-80 (1997) NOVEMBER II 1997, PAGE73 BV RI photometric sequences for nine selected dark globules J.F. Lahulla 1, A. Aguirre
More informationarxiv:astro-ph/ v1 1 Apr 2004
Mc Neil s Nebula in Orion: The Outburst History 1 C. Briceño 2, A.K. Vivas, J. Hernández 3 Centro de Investigaciones de Astronomía (CIDA), Apartado Postal 264, Mérida 5101-A, Venezuela arxiv:astro-ph/0404012v1
More informationPart III: Circumstellar Properties of Intermediate-Age PMS Stars
160 Part III: Circumstellar Properties of Intermediate-Age PMS Stars 161 Chapter 7 Spitzer Observations of 5 Myr-old Brown Dwarfs in Upper Scorpius 7.1 Introduction Ground-based infrared studies have found
More informationKeeping an Eye on the Young: Monitoring T Tauri Stars
Keeping an Eye on the Young: Monitoring T Tauri Stars T Tauri stars are young (0.5-5 Myr), low mass (0.1-1 solar mass) stars. They are typically found in close association with the gas & dust clouds out
More informationInvestigating the Efficiency of the Beijing Faint Object Spectrograph and Camera (BFOSC) of the Xinglong 2.16-m Reflector
Research in Astron. Astrophys. Vol. (xx) No., http://www.raa-journal.org http://www.iop.org/journals/raa Research in Astronomy and Astrophysics Investigating the Efficiency of the Beijing Faint Object
More informationYoung stellar objects and their environment
Recent Advances in Star Formation: Observations and Theory ASI Conference Series, 2012, Vol. 4, pp 107 111 Edited by Annapurni Subramaniam & Sumedh Anathpindika Young stellar objects and their environment
More informationStar formation in the region of young open cluster - NGC 225
Bull. Astr. Soc. India (2006) 34, 315 325 Star formation in the region of young open cluster - NGC 225 Annapurni Subramaniam 1, Blesson Mathew 1 and Sreeja S. Kartha 1,2 1 Indian Institute of Astrophysics,
More informationThe Protostellar Luminosity Function
Design Reference Mission Case Study Stratospheric Observatory for Infrared Astronomy Science Steering Committee Program contacts: Lynne Hillenbrand, Tom Greene, Paul Harvey Scientific category: STAR FORMATION
More informationMethods of Determining Relative Age of Young Stellar Objects Zak Schroeder, Nathan Stano, Graham Kozak Teacher: Ardis Herrold
Methods of Determining Relative Age of Young Stellar Objects Zak Schroeder, Nathan Stano, Graham Kozak Teacher: Ardis Herrold ABSTRACT The main goal of the project was to study various types of Young Stellar
More informationIntroduction to SDSS -instruments, survey strategy, etc
Introduction to SDSS -instruments, survey strategy, etc (materials from http://www.sdss.org/) Shan Huang 17 February 2010 Survey type Status Imaging and Spectroscopy Basic Facts SDSS-II completed, SDSS-III
More informationProtoplanetary discs of isolated VLMOs discovered in the IPHAS survey
Protoplanetary discs of isolated VLMOs discovered in the IPHAS survey Luisa Valdivielso Casas Collaborators: E. Martín, H. Bouy, E. Solano,J. Drew,R. Greimel 1 IAC - ULL 14 de septiembre 2010 Outline Introduction
More informationLecture 26 Low-Mass Young Stellar Objects
Lecture 26 Low-Mass Young Stellar Objects 1. Nearby Star Formation 2. General Properties of Young Stars 3. T Tauri Stars 4. Herbig Ae/Be Stars References Adams, Lizano & Shu ARAA 25 231987 Lada OSPS 1999
More informationSearch for envelopes of some stellar planetary nebulae, symbiotic stars and further emission-line objects
ASTRONOMY & ASTROPHYSICS NOVEMBER I 1997, PAGE 445 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 125, 445-451 (1997) Search for envelopes of some stellar planetary nebulae, symbiotic stars and further
More informationDetectors for IR astronomy
Detectors for IR astronomy Where does infrared begin? Wavelength sensi?vity of the human eye vs. wavelength Note: the eye has some (limited) sensi?vity to IR light at ~1000nm (=0.5x energy of photons the
More informationThe HII Regions of Sextans A
Publications of the Astronomical Society of the Pacific 6: 765-769, 1994 July The HII Regions of Sextans A Paul Hodge 1 Astronomy Department, University of Washington, Seattle, Washington 98195 Electronic
More informationarxiv: v1 [astro-ph] 3 Oct 2007
Peremennye Zvezdy 27, No.4, 2007 Variable Stars 27, No.4, 2007 SAI, INASAN, Astronet.ru Moscow, Russia 3 October 2007 arxiv:0710.0765v1 [astro-ph] 3 Oct 2007 PHOTOMETRIC OBSERVATIONS OF SUPERNOVA 2002hh
More informationThe FU Orionis Binary System and the Formation of Close Binaries 1
Accepted by ApJ Letters The FU Orionis Binary System and the Formation of Close Binaries 1 Bo Reipurth 1 and Colin Aspin 2 1: Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu,
More informationA parsec-scale flow associated with the IRAS radio jet
submitted to The Astrophysical Journal Letters A parsec-scale flow associated with the IRAS 16547 4247 radio jet Kate J. Brooks Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago,
More informationHigh Resolution Optical Spectra of HBC 722 after Outburst
Journal of The Korean Astronomical Society doi:10.5303/jkas.2011.??.??.1??: 1 4, 2011 April ISSN:1225-4614 c 2011 The Korean Astronomical Society. All Rights Reserved. http://jkas.kas.org High Resolution
More informationBV R photometry of comparison stars in selected blazar fields
ASTRONOMY & ASTROPHYSICS JUNE I 1998, PAGE 305 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 130, 305 310 (1998) BV R photometry of comparison stars in selected blazar fields I. Photometric sequences
More informationInfra-red imaging of perpendicular nested bars in spiral galaxies with the Infra-red Camera at the Carlos Sanchez Telescope
Infra-red imaging of perpendicular nested bars in spiral galaxies with the Infra-red Camera at the Carlos Sanchez Telescope S.N. Kemp (skemp@ll.iac.es) Instituto de Astrofísica de Canarias, E-38200 La
More informationExploring the substellar IMF in the Taurus cloud
Mem. S.A.It. Vol. 76, 253 c SAIt 2005 Memorie della Exploring the substellar IMF in the Taurus cloud New brown dwarfs in the Taurus star forming region S. Guieu 1, C. Dougados 1, J.-L. Monin 1,4, E. Magnier
More informationMeasurement of the stellar irradiance
Measurement of the stellar irradiance Definitions Specific Intensity : (monochromatic) per unit area normal to the direction of radiation per unit solid angle per unit wavelength unit (or frequency) per
More informationTrES Exoplanets and False Positives: Finding the Needle in the Haystack
Transiting Extrasolar Planets Workshop ASP Conference Series, Vol. 366, 2007 C. Afonso, D. Weldrake and Th. Henning TrES Exoplanets and False Positives: Finding the Needle in the Haystack F. T. O Donovan
More informationStar formation : circumstellar environment around Young Stellar Objects
Bull. Astr. Soc. India (2005) 33, 327 331 Star formation : circumstellar environment around Young Stellar Objects Manoj Puravankara Inter-University Centre for Astronomy and Astrophysics, Pune - 411007,
More informationA Multi-Wavelength Study of the Outburst of V1647 Orionis
A Multi-Wavelength Study of the 03 06 Outburst of V1647 Orionis Mario van den Ancker 1 Davide Fedele 1,2,3 Monika Petr-Gotzens 1 Piero Rafanelli 3 1 ESO 2 Max-Planck Institut für Astronomie, Heidelberg,
More informationAnalysis of the rich optical iron-line spectrum of the x-ray variable I Zw 1 AGN 1H
Analysis of the rich optical iron-line spectrum of the x-ray variable I Zw 1 AGN 1H0707 495 H Winkler, B Paul Department of Physics, University of Johannesburg, PO Box 524, 2006 Auckland Park, Johannesburg,
More informationA Calibration Method for Wide Field Multicolor. Photometric System 1
A Calibration Method for Wide Field Multicolor Photometric System 1 Xu Zhou,Jiansheng Chen, Wen Xu, Mei Zhang... Beijing Astronomical Observatory,Chinese Academy of Sciences, Beijing 100080, China Beijing
More informationThe Infrared Universe as Seen by Spitzer and Beyond. February 20, 2007
The Infrared Universe as Seen by Spitzer and Beyond The Holly Berry Cluster [NOT the Halle Berry cluster] in Serpens February 20, 2007 Presented to the Herschel Open Time Key Project Workshop Michael Werner,
More informationPMS OBJECTS IN THE STAR FORMATION REGION Cep OB3. II. YOUNG STELLAR OBJECTS IN THE Ha NEBULA Cep B
Astrophysics, Vol. 56, No. 2, June, 2013 PMS OBJECTS IN THE STAR FORMATION REGION Cep OB3. II. YOUNG STELLAR OBJECTS IN THE Ha NEBULA Cep B E. H. Nikoghosyan Models for the spectral energy distributions
More informationLab 4: Stellar Spectroscopy
Name:... Astronomy 101: Observational Astronomy Fall 2006 Lab 4: Stellar Spectroscopy 1 Observations 1.1 Objectives and Observation Schedule During this lab each group will target a few bright stars of
More informationA Search for New Solar-Type Post-T Tauri Stars in the Taurus-Auriga and Scorpius-Centaurus Regions
Galaxy Evolution Explorer(GALEX) Cycle 1 Guest Investigator Proposal A Search for New Solar-Type Post-T Tauri Stars in the Taurus-Auriga and Principal Investigator: Institution: Department of Astronomy/Astrophysics
More informationHigh Redshift Universe
High Redshift Universe Finding high z galaxies Lyman break galaxies (LBGs) Photometric redshifts Deep fields Starburst galaxies Extremely red objects (EROs) Sub-mm galaxies Lyman α systems Finding high
More informationThe Optical Microvariability and Spectral Changes of the BL Lacertae Object S
J. Astrophys. Astr. (2011) 32, 97 103 c Indian Academy of Sciences The Optical Microvariability and Spectral Changes of the BL Lacertae Object S5 0716+714 H. Poon 1,, J.H.Fan 2 & J.N.Fu 1 1 Astronomy Department,
More informationPhotometric and spectroscopic observations of the outburst of the symbiotic star AG Draconis between March and June 2016
Photometric and spectroscopic observations of the outburst of the symbiotic star AG Draconis between March and June 2016 David Boyd Variable Star Section, British Astronomical Association, [davidboyd@orion.me.uk]
More informationLab 4 Radial Velocity Determination of Membership in Open Clusters
Lab 4 Radial Velocity Determination of Membership in Open Clusters Sean Lockwood 1, Dipesh Bhattarai 2, Neil Lender 3 December 2, 2007 Abstract We used the Doppler velocity of 29 stars in the open clusters
More informationUniversitetskij Pr. 13, Moscow , Russia; mx.iki.rssi.ru
Central stars of mid-infrared nebulae discovered with Spitzer and WISE arxiv:1611.01155v1 [astro-ph.sr] 3 Nov 2016 V.V. Gvaramadze 1,2 and A.Y. Kniazev 1,3,4 1 Sternberg Astronomical Institute, Lomonosov
More informationFormation and Evolution of Planetary Systems
Formation and Evolution of Planetary Systems Meyer, Hillenbrand et al., Formation and Evolution of Planetary Systems (FEPS): First Results from a Spitzer Legacy Science Program ApJ S 154: 422 427 (2004).
More informationarxiv:astro-ph/ v1 26 Jan 2001
Submitted to Astron. J. Circumstellar Disks in the IC 348 Cluster Karl E. Haisch Jr. 1,2 and Elizabeth A. Lada 2,3 Dept. of Astronomy, University of Florida, 211 SSRB, Gainesville, FL 32611 arxiv:astro-ph/0101486v1
More informationThe HST Set of Absolute Standards for the 0.12 µm to 2.5 µm Spectral Range
Instrument Science Report CAL/SCS-010 The HST Set of Absolute Standards for the 0.12 µm to 2.5 µm Spectral Range L. Colina, R. Bohlin, D. Calzetti, C. Skinner, S. Casertano October 3, 1996 ABSTRACT A proposal
More informationAN OPTICAL-IR COUNTERPART FOR SGR B1900+l4? and. 1. Introduction
AN OPTICAL-IR COUNTERPART FOR SGR B1900+l4? F. J. VRBA, C. B. LUGINBUHL U.S. Naval Observatory Flagstaff Station, P.O. Box 1149, Flagstaff AZ 86002-1149, USA D. HARTMANN Department of Physics and Astronomy,
More informationTime-variable phenomena in Herbig Ae/Be stars
Time-variable phenomena in Herbig Ae/Be stars! Péter Ábrahám Konkoly Observatory, Budapest, Hungary! Á. Kóspál, R. Szakáts! Santiago, 2014 April 7 Variability - and why it is interesting Herbig Ae/Be stars
More informationarxiv: v2 [astro-ph.ep] 2 Nov 2017
Palomar Optical Spectrum of Hyperbolic Near-Earth Object A/2017 U1 Joseph R. Masiero 1 ABSTRACT arxiv:1710.09977v2 [astro-ph.ep] 2 Nov 2017 We present optical spectroscopy of the recently discovered hyperbolic
More informationHigh Energy Processes in Young Stellar Objects
High Energy Processes in Young Stellar Objects Ji Wang Department of Astronomy, University of Florida, Gainesville, Fl 32601 jwang@astro.ufl.edu Received ; accepted 2 ABSTRACT In this paper, I present
More informationNEAR-INFRARED PHOTOMETRY OF BLAZARS
NEAR-INFRARED PHOTOMETRY OF BLAZARS C. Chapuis 1,2,S.Corbel 1, P. Durouchoux 1,T.N.Gautier 3, and W. Mahoney 3 1) Service d Astrophysique DAPNIA, CEA Saclay F-91191 Gif sur Yvette cedex 2) Département
More informationExtraction of Point Source Spectra from STIS Long Slit Data
1997 HST Calibration Workshop Space Telescope Science Institute, 1997 S. Casertano, et al., eds. Extraction of Point Source Spectra from STIS Long Slit Data J. R. Walsh Spect Telescope European Coordinating
More informationCHEMICAL ABUNDANCES OF WEAK T TAURI STARS
CHEMICAL ABUNDANCES OF WEAK T TAURI STARS Gustavo de Araujo Rojas Universidade de São Paulo Instituto de Astronomia, Geofísica e Ciências Atmosféricas rojas@astro.iag.usp.br Jane Gregorio-Hetem Universidade
More informationPhotometric and spectroscopic observations of the 2014 eclipse of the complex binary EE Cephei
Photometric and spectroscopic observations of the 2014 eclipse of the complex binary EE Cephei David Boyd Variable Star Section, British Astronomical Association, [davidboyd@orion.me.uk] Abstract We report
More informationarxiv: v2 [astro-ph.sr] 16 May 2013
Pulsation Analysis of the High Amplitude δ Scuti Star CW Serpentis J. S. Niu arxiv:1304.3770v2 [astro-ph.sr] 16 May 2013 Astronomy Department, Beijing Normal University, Beijing 100875, China J. N. Fu
More informationTECHNICAL REPORT. Doc #: Date: Rev: JWST-STScI , SM-12 August 31, Authors: Karl Gordon, Ralph Bohlin. Phone:
When there is a discrepancy between the information in this technical report and information in JDox, assume JDox is correct. TECHNICAL REPORT Title: Title: JWST Absolute Flux Calibration II: Expanded
More informationInfrared Spectroscopy of the Black Hole Candidate GRO J
Infrared Spectroscopy of the Black Hole Candidate GRO J1655-40 1 Francis T. O Donovan March 19th, 2004 1 Based on a paper by F. T. O Donovan & P. J. Callanan (in preparation). Black Holes in the Sky At
More informationStar Formation. Spitzer Key Contributions to Date
Star Formation Answering Fundamental Questions During the Spitzer Warm Mission Phase Lori Allen CfA John Carpenter, Caltech Lee Hartmann, University of Michigan Michael Liu, University of Hawaii Tom Megeath,
More informationThe Wolf-Rayet + O binary WR 140 in Cygnus
The Wolf-Rayet + O binary WR 140 in Cygnus http://spektroskopie.fg-vds.de Fachgruppe SPEKTROSKOPIE 1. The system The archetype of colliding-wind binary (CWB) systems is the 7.9-year period WR+O binary
More informationAn atlas of images of Planetary Nebulae
ASTRONOMY & ASTROPHYSICS APRIL I 1999, PAGE 145 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 136, 145 171 (1999) An atlas of images of Planetary Nebulae S.K. Górny 1,H.E.Schwarz 2, R.L.M. Corradi 3,
More information125-Day Spectral Record of the Bright Nova Delphini 2013 (V339 Del)
Mooers and Wiethoff, JAAVSO Volume 42, 2014 161 125-Day Spectral Record of the Bright Nova Delphini 2013 (V339 Del) Howard D. Mooers Department of Geological Sciences, University of Minnesota Duluth, Duluth,
More informationFLAMINGOS SPECTROSCOPY OF NEW LOW-MASS MEMBERS OF THE YOUNG CLUSTER IC 348
The Astrophysical Journal, 618:810 816, 2005 January 10 # 2005. The American Astronomical Society. All rights reserved. Printed in U.S.A. FLAMINGOS SPECTROSCOPY OF NEW LOW-MASS MEMBERS OF THE YOUNG CLUSTER
More informationX-RAY VIEW OF V1647 ORI, THE YOUNG STAR IN OUTBURST ILLUMINATING MCNEIL S NEBULA
1 X-RAY VIEW OF V1647 ORI, THE YOUNG STAR IN OUTBURST ILLUMINATING MCNEIL S NEBULA N. Grosso Laboratoire d Astrophysique de Grenoble, Université Joseph-Fourier, 38041 Grenoble, France ABSTRACT McNeil s
More informationQuasars and Active Galactic Nuclei (AGN)
Quasars and Active Galactic Nuclei (AGN) Astronomy Summer School in Mongolia National University of Mongolia, Ulaanbaatar July 21-26, 2008 Kaz Sekiguchi Hubble Classification M94-Sa M81-Sb M101-Sc M87-E0
More informationSURVEYING THE SUBSTELLAR COMPONENT OF THE ORION DISPERSED POPULATIONS
SURVEYING THE SUBSTELLAR COMPONENT OF THE ORION DISPERSED POPULATIONS Juan José Downes (1,2), César Briceño (1), Jesús Hernández (1), Nuria Calvet (3) & Lee Hartmann (3) WITH THE COLLABORATION OF: Cecilia
More informationarxiv: v2 [astro-ph] 18 Sep 2007
Discovery of Gas Accretion Onto Stars in 13 Myr old h and χ Persei Thayne Currie 1, Scott J. Kenyon 1, Zoltan Balog 2,3, Ann Bragg 4, & Susan Tokarz 1 arxiv:0709.1847v2 [astro-ph] 18 Sep 2007 tcurrie@cfa.harvard.edu
More informationSpitzer Space Telescope
Spitzer Space Telescope (A.K.A. The Space Infrared Telescope Facility) The Infrared Imaging Chain 1/38 The infrared imaging chain Generally similar to the optical imaging chain... 1) Source (different
More informationOptical positions of compact extragalactic radio sources with respect to the Hipparcos Catalogue
ASTRONOMY & ASTROPHYSICS AUGUST 1998, PAGE 259 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 131, 259 263 (1998) Optical positions of compact extragalactic radio sources with respect to the Hipparcos
More informationMeasuring the Redshift of M104 The Sombrero Galaxy
Measuring the Redshift of M104 The Sombrero Galaxy Robert R. MacGregor 1 Rice University Written for Astronomy Laboratory 230 Department of Physics and Astronomy, Rice University May 3, 2004 2 Abstract
More informationAstronomy 1 Fall 2016
Astronomy 1 Fall 2016 Lecture11; November 1, 2016 Previously on Astro-1 Introduction to stars Measuring distances Inverse square law: luminosity vs brightness Colors and spectral types, the H-R diagram
More informationarxiv:astro-ph/ v1 13 Aug 2003
The Discovery of a Twelfth Wolf-Rayet Star in the Small Magellanic Cloud Philip Massey 1 arxiv:astro-ph/0308237v1 13 Aug 2003 Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001 Phil.Massey@lowell.edu
More informationGOODS/FORS2 Final Data Release: Version 3.0
ESO Phase 3 Data Release Description Data Collection GOODS_FORS2 Release Number 1 Data Provider C. Cesarsky Date 30.10.2007 update 11.07.2014 GOODS/FORS2 Final Data Release: Version 3.0 As part of the
More informationTHE ABSOLUTE DIMENSIONS OF THE OVERCONTACT BINARY FI BOOTIS
The Astronomical Journal, 132:1153Y1157, 2006 September # 2006. The American Astronomical Society. All rights reserved. Printed in U.S.A. A THE ABSOLUTE DIMENSIONS OF THE OVERCONTACT BINARY FI BOOTIS Dirk
More informationNICMOS Status and Plans
1997 HST Calibration Workshop Space Telescope Science Institute, 1997 S. Casertano, et al., eds. NICMOS Status and Plans Rodger I. Thompson Steward Observatory, University of Arizona, Tucson, AZ 85721
More informationNon-Profit Academic Project, developed under the Open Acces Initiative
Red de Revistas Científicas de América Latina, el Caribe, España y Portugal Sistema de Información Científica Armen. L. Gyulbudaghian, Jorge May, L. Gonzáles, R. A. Méndez Nebulous Objects in the Southern
More informationDetermining the Orbital Period of the Cataclysmic Variable CSS1204 Using Data from the Vatican Advanced Technology Telescope
Determining the Orbital Period of the Cataclysmic Variable CSS1204 Using Data from the Vatican Advanced Technology Telescope Amy Applegate 2012 NSF/REU Program Physics Department, University of Notre Dame
More informationAstrophysical False Positives Encountered in Wide-Field Transit Searches
Astrophysical False Positives Encountered in Wide-Field Transit Searches David Charbonneau, Timothy M. Brown, Edward W. Dunham, David W. Latham, Dagny L. Looper and Georgi Mandushev California Institute
More informationObservations of Bn and An stars: New Be stars
ASTRONOMY & ASTROPHYSICS JANUARY II 1999, PAGE 359 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 134, 359 364 (1999) Observations of Bn and An stars: New Be stars K.K. Ghosh 1,2,, K.M.V. Apparao 3 and
More informationSeptember 2008 LGS Science Observing Plan 9/18/08 v1.1, A. Bouchez
1. General Procedures September 2008 LGS Science Observing Plan 9/18/08 v1.1, A. Bouchez We should attempt to complete highest priority observing programs first, before proceeding to lower priority programs.
More informationCEPHEUS OB2: DISK EVOLUTION AND ACCRETION AT 3 10 Myr 1
The Astronomical Journal, 130:188 209, 2005 July # 2005. The American Astronomical Society. All rights reserved. Printed in U.S.A. A CEPHEUS OB2: DISK EVOLUTION AND ACCRETION AT 3 10 Myr 1 Aurora Sicilia-Aguilar,
More informationTemperature, Blackbodies & Basic Spectral Characteristics.
Temperature, Blackbodies & Basic Spectral Characteristics. Things that have one primary temperature but also exhibit a range of temperatures are known in physics as blackbodies. They radiate energy thermally.
More informationarxiv: v2 [astro-ph.sr] 24 Aug 2010
The FUor Candidate V582 Aurigae: First Photometric and Spectroscopic Observations arxiv:1008.3899v2 [astro-ph.sr] 24 Aug 2010 Evgeni H. Semkov 1, Stoyanka P. Peneva 1, Michel Dennefeld 2 1 Institute of
More informationAnalyzing Spiral Galaxies Observed in Near-Infrared
Analyzing Spiral Galaxies Observed in Near-Infrared Preben Grosbøl European Southern Observatory Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany Abstract A sample of 54 spiral galaxies was observed
More informationHigh quality seeing V, I and Gunn z imaging of Terzan 4: a blue horizontal branch bulge globular cluster
Astron. Astrophys. 319, 850 854 (1997) ASTRONOMY AND ASTROPHYSICS High quality seeing V, I and Gunn z imaging of Terzan 4: a blue horizontal branch bulge globular cluster S. Ortolani 1, B. Barbuy 2, and
More informationResults of the ESO-SEST Key Programme: CO in the Magellanic Clouds. V. Further CO observations of the Small Magellanic Cloud
ASTRONOMY & ASTROPHYSICS AUGUST 1996, PAGE 263 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 118, 263-275 (1996) Results of the ESO-SEST Key Programme: CO in the Magellanic Clouds. V. Further CO observations
More informationRadio Nebulae around Luminous Blue Variable Stars
Radio Nebulae around Luminous Blue Variable Stars Claudia Agliozzo 1 G. Umana 2 C. Trigilio 2 C. Buemi 2 P. Leto 2 A. Ingallinera 1 A. Noriega-Crespo 3 J. Hora 4 1 University of Catania, Italy 2 INAF-Astrophysical
More informationThe 25 Orionis cluster: hunting ground for young exoplanets
The 25 Orionis cluster: hunting ground for young exoplanets César Briceño CIDA, Mérida, Venezuela Collaborators: Kathy Vivas, Jesús Hernández, Juan José Downes, Cecilia Mateu (CIDA, Venezuela) Nuria Calvet,
More informationExploring Data. Keck LRIS spectra. Handbook of CCD Astronomy by Steve Howell Chap. 4, parts of 6
Exploring Data Keck LRIS spectra Handbook of CCD Astronomy by Steve Howell Chap. 4, parts of 6 FITS: Flexible Image Transport System Digital file format used to store astronomical images, data, and catalogs.
More informationStar Formation. Answering Fundamental Questions During the Spitzer Warm Mission Phase
Star Formation Answering Fundamental Questions During the Spitzer Warm Mission Phase Lori Allen CfA John Carpenter, Caltech Lee Hartmann, University of Michigan Michael Liu, University of Hawaii Tom Megeath,
More informationRevealing new optically-emitting extragalactic Supernova Remnants
10 th Hellenic Astronomical Conference Ioannina, September 2011 Revealing new optically-emitting extragalactic Supernova Remnants Ioanna Leonidaki (NOA) Collaborators: P. Boumis (NOA), A. Zezas (UOC, CfA)
More informationSpectral classification and determination of the star distances using Hα emission line
THE SKY AS A LABORATORY 2008/2009 55 Spectral classification and determination of the star distances using Hα emission line Fabio Lonardi (1), Michele Piccoli (1), Leonardo Manzati (2) (1) Liceo scientifico
More informationOptical spectroscopic and 2MASS measurements of Stephenson H α stars. G. Maheswar, P. Manoj, and H. C. Bhatt
A&A 402, 963 970 (2003) DOI: 10.1051/0004-6361:20030315 c ESO 2003 Astronomy & Astrophysics Optical spectroscopic and 2MASS measurements of Stephenson H α stars G. Maheswar, P. Manoj, and H. C. Bhatt Indian
More informationFlux Units and Line Lists
APPENDIX 2 Flux Units and Line Lists In This Appendix... Infrared Flux Units / 255 Formulae / 258 Look-up Tables / 259 Examples / 266 Infrared Line Lists / 266 In this chapter we provide a variety of background
More informationVY Canis Majoris: The Astrophysical Basis of Its Luminosity
VY Canis Majoris: The Astrophysical Basis of Its Luminosity Roberta M. Humphreys School of Physics and Astronomy, University of Minnesota, 55455 ABSTRACT arxiv:astro-ph/0610433v1 13 Oct 2006 The luminosity
More informationInfrared L Band Observations of the Trapezium Cluster: A Census of Circumstellar Disks and Candidate Protostars
To Appear in the December 2000 Astronomical Journal Infrared L Band Observations of the Trapezium Cluster: A Census of Circumstellar Disks and Candidate Protostars Charles J. Lada arxiv:astro-ph/0008280
More informationWHAT DO RADIAL VELOCITY MEASUREMENTS TELL ABOUT RV TAURI STARS?
Dig Sites of Stellar Archeology: Giant Stars in the Milky Way Ege Uni. J. of Faculty of Sci., Special Issue, 2014, 113-120 WHAT DO RADIAL VELOCITY MEASUREMENTS TELL ABOUT RV TAURI STARS? Timur Şahin 1*,
More informationReduction procedure of long-slit optical spectra. Astrophysical observatory of Asiago
Reduction procedure of long-slit optical spectra Astrophysical observatory of Asiago Spectrograph: slit + dispersion grating + detector (CCD) It produces two-dimension data: Spatial direction (x) along
More information1. The AGB dust budget in nearby galaxies
**Volume Title** ASP Conference Series, Vol. **Volume Number** **Author** c **Copyright Year** Astronomical Society of the Pacific Identifying the chemistry of the dust around AGB stars in nearby galaxies
More informationIntroduction to Stellar Spectra
Introduction to Stellar Spectra We are about to start down a long road as we search for the chemical composition of the stars. The journey won't be short, or easy, but along the way you'll meet a number
More informationarxiv: v1 [astro-ph.sr] 17 Oct 2012
ACTA ASTRONOMICA Vol. 62 (2012) pp. 247 268 Photometric Maps Based on the OGLE-III Shallow Survey in the Large Magellanic Cloud arxiv:1210.4702v1 [astro-ph.sr] 17 Oct 2012 K. U l a c z y k 1, M. K. S z
More informationTNG photometry of the open cluster NGC 6939
Mem. S.A.It. Vol. 75, 19 c SAIt 2004 Memorie della TNG photometry of the open cluster NGC 6939 G. Andreuzzi 1, A. Bragaglia 2, M. Tosi 2 and G. Marconi 3 1 INAF Osservatorio Astronomico di Roma, via Frascati
More informationTransiting Exoplanet in the Near Infra-red for the XO-3 System
Transiting Exoplanet in the Near Infra-red for the XO-3 System Nathaniel Rodriguez August 26, 2009 Abstract Our research this summer focused on determining if sufficient precision could be gained from
More informationnovae, cataclysmic variables stars: individual: V2659 Cyg
Baltic Astronomy, vol. 24, 345 352, 2015 EARLY PHOTOMETRIC AND SPECTRAL EVOLUTION OF NOVA CYGNI 2014 (V2659 CYG) M. A. Burlak, V. F. Esipov and G. V. Komissarova Sternberg Astronomical Institute, M. V.
More informationMillimetre Science with the AT
Millimetre Science with the AT Astrochemistry with mm-wave Arrays G.A. Blake, Caltech 29Nov 2001 mm-arrays: Important Features - Spatial Filtering - Transform to image plane - Cross Correlation (Sub)Millimeter
More informationPossibilities for observations of exoplanets in Bulgaria ( and results up to now)
Workshop Young Planetary Systems Possibilities for observations of exoplanets in Bulgaria ( and results up to now) Dinko Dimitrov Institute of Astronomy, BAS and Diana Kjurkchieva Shumen University November
More information