- ID:
- ivo://CDS.VizieR/J/ApJS/225/26
- Title:
- Very Low-Luminosity Objects (VeLLOs) from 1.25-850um
- Short Name:
- J/ApJS/225/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for Very Low-Luminosity Objects (VeLLOs) in the Gould Belt (GB) clouds using infrared and sub-millimeter (sub-mm) data from 1.25 to 850{mu}m and our N_2_H^+^(J=1-0) observations. We modified the criteria by Dunham et al. (2008, J/ApJS/179/249) to select the VeLLOs in the GB clouds, finding 95 VeLLO candidates, 79 of which are newly identified in this study. Out of 95 sources, 44 were detected in both sub-mm continuum and N_2_H^+^ emission and were classified as Group A (the VeLLOs), and 51 sources detected in either sub-mm emission or N_2_H^+^ emission were classified with Group B as candidate VeLLOs. We find that these VeLLOs and the candidates are forming in environments different from those of the likely VeLLOs. Seventy-eight sources are embedded within their molecular clouds, and thus are likely VeLLOs forming in a dense environment. The remaining 17 sources are located in low-level extinction regions (A_V_<1) connected to the clouds, and can be either background sources or candidate substellar objects forming in an isolated mode. The VeLLOs and the candidates are likely more luminous and their envelopes tend to be more massive in denser environments. The VeLLOs and the candidates are more populous in the clouds where more YSOs form, indicating that they form in a manner similar to that of normal YSOs. The bolometric luminosities and temperatures of the VeLLOs are compared to predictions of episodic accretion models, showing that the low luminosities for most VeLLOs can be well explained by their status in the quiescent phases of a cycle of episodic mass accretion.
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- ID:
- ivo://CDS.VizieR/J/A+A/572/A44
- Title:
- Vibrationally excited vinyl cyanide in Orion-KL
- Short Name:
- J/A+A/572/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Laboratory characterization (18-1893 GHz) and astronomical detection (IRAM-30m: 80-280GHz, Orion-KL) of CH_2_CHCN (vinyl cyanide) in its ground and vibrationally excited states. Improving the understanding of rotational spectra of vibrationally excited vinyl cyanide with new laboratory data and analysis. The laboratory results allow searching for these excited state transitions in the Orion-KL line survey. Furthermore, rotational lines of CH_2_CHCN contribute to the understanding of the physical and chemical properties of the cloud. Laboratory measurements of CH_2_CHCN made on several different frequency-modulated spectrometers were combined into a single broadband 50-1900GHz spectrum and its assignment was confirmed by Stark modulation spectra recorded in the 18-40GHz region and by ab-initio anharmonic force field calculations. For analyzing the emission lines of vinyl cyanide detected in Orion-KL we used the excitation and radiative transfer code (MADEX) at LTE conditions. Detailed characterisation of laboratory spectra of CH_2CHCN in 9 different excited vibrational states (v_11_=1, v_15_=1, v_11_=2, v_10_=1<==>(v_11_=1,v_15_=1), v_11_=3/v_15_=2/v_14_=1, (v_11_=1,v_10_=1)<==>(v_11_=2, v_15_=1), v_9_$=1, (v_11_=1,v_15_=2)<==>(v_10_=1, v_15_=1)<==>(v_11_=1,v_14_=1), and v_11_=4) and detection of transitions in the v_11_=2 and v_11_=3 states for the first time in Orion-KL, and of those in the v_10_=1<==>(v_11_=1,v_15_=1) dyad of states for the first time in space. The rotational transitions of the ground state of this molecule emerge from four cloud components of hot core nature which trace the physical and chemical conditions of high mass star forming regions in the Orion-KL Nebula. The lowest energy vibrationally excited states of vinyl cyanide such as v_11_=1 (at 328.5K), v_15_=1 (at 478.6K), v_11_=2 (at 657.8K), the v_10_=1<==>(v_11_=1,v_15_=1) dyad (at 806.4/809.9K), and v_11_=3 (at 987.9K) are populated under warm and dense conditions, so they probe the hottest parts of the Orion-KL source. The vibrational temperatures derived for the v_11_=1, v_11_=2, and v_15_=1 states are 252+/-76K, 242+/-121K, and 227+/-68K, respectively; all of them close to the mean kinetic temperature of the hot core component (210K). The total column density of CH_2_CHCN in the ground state is (3.0+/-0.9)x10^15^cm^-2^. We report the detection of methyl isocyanide (CH_3_NC) for the first time in Orion-KL and a tentative detection of vinyl isocyanide (CH_2_CHNC) and give column density ratios between the cyanide and isocyanide isomers obtaining a N(CH_3_NC)/N(CH_3_CN) ratio of 0.002. Laboratory characterisation of many previously unassigned vibrationally excited states of vinyl cyanide at microwave to THz frequencies allowed us to detect these molecular species in Orion-KL. Column density and rotational and vibrational temperatures for CH_2_CHCN in their ground and excited states, as well as for the isotopologues, have been constrained by means of a sample of more than 1000 lines in this survey.
- ID:
- ivo://CDS.VizieR/J/BaltA/12/301
- Title:
- Vilnius photometry in Barnard 1
- Short Name:
- J/BaltA/12/301
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectral and luminosity classes, absolute magnitudes. color excesses, interstellar extinctions and distances are determined for 98 stars down to 13mag in the Barnard 1 dark cloud belonging to the Per OB2 association. The classification of stars is based on their photoelectric photometry in the Vilnius seven-color photometric system. The extinction vs. distance diagram exhibits the presence of two dust layers at 150 and 230pc distances. The distance of the first cloud, which gives an extinction AV of 0.3mag, coincides with the distance of the Taurus dark cloud complex. The second cloud with much larger extinction is about at the same distance as the clouds in the direction of the nearby objects: reflection nebula NGC 1333 and open cluster IC 348.
- ID:
- ivo://CDS.VizieR/J/BaltA/10/349
- Title:
- Vilnius photometry in Cam/Per
- Short Name:
- J/BaltA/10/349
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 157 stars down to 11th mag in a 3{deg}x4{deg} area at l=149{deg}, b=-0.3{deg} have been measured in the Vilnius photometric system. Magnitudes V, color indices, spectral classes, absolute magnitudes, color excesses and distances of the stars are determined. The interstellar extinction in all the area appears at a distance of about 100pc, grows monotonically and at a distance of 500pc it reaches ~2mag in the area of the dark cloud L1391 and 0.7-1.7mag in the remaining area. At larger distances the extinction is affected by a selection effect.
- ID:
- ivo://CDS.VizieR/J/BaltA/11/75
- Title:
- Vilnius photometry in Cam-Per border
- Short Name:
- J/BaltA/11/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Seven-color photometry in the Vilnius system for 309 stars down to 12.5mag in the area along the galactic equator near the Camelopardalis and Perseus border is presented. Photometric spectral and luminosity classes of the stars are determined.
- ID:
- ivo://CDS.VizieR/J/BaltA/15/483
- Title:
- Vilnius photometry in LDN 935
- Short Name:
- J/BaltA/15/483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnitudes and color indices of 439 stars down to V~17.5mag in the eight-color Vilnius + I photometric system were obtained in four areas of diameters 20' within the dark cloud L935 separating the North America and Pelican nebulae. Spectral types, interstellar color excesses, extinctions and distances of stars were determined from the photometric data.
- ID:
- ivo://CDS.VizieR/J/BaltA/11/219
- Title:
- Vilnius photometry in MBM12
- Short Name:
- J/BaltA/11/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of photoelectric photometry in the Vilnius seven-color system are given for 152 stars down to 12.2mag in the area of the molecular cloud MBM 12 and the dust clouds L1454 and L1457 in Aries. The results of photometric classification of stars are also given. The investigation of interstellar extinction in the area is described in the next paper, Straizys et al., Cat. <J/BaltA/11/231>.
- ID:
- ivo://CDS.VizieR/J/BaltA/11/321
- Title:
- Vilnius photometry in Serpens cauda. I.
- Short Name:
- J/BaltA/11/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of photoelectric photometry in the Vilnius seven-color system and photometric classification are given for 419 stars down to ~11.0mag in a 5x10sq. degree area in the direction of the Serpens Cauda dark clouds.
- ID:
- ivo://CDS.VizieR/J/BaltA/22/243
- Title:
- Vilnius photometry of TGU H994
- Short Name:
- J/BaltA/22/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of CCD photometry in the seven-color Vilnius system are given for 727 stars down to V~17 mag in a 1.5 square degree field in the region of dark cloud TGU H994 P1 (or LDN 1399, LDN 1400 and LDN 1402) in Camelopardalis. Using the intrinsic color indices and photometric reddening-free Q-parameters, two-dimensional spectral types for 73% of stars are determined.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A31
- Title:
- Vilnius photometry of TGU H994 P1
- Short Name:
- J/A+A/585/A31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of CCD photometry in the seven-color Vilnius system are given for 855 stars down to V~20mag in three 12x12 arcmin areas of the dark cloud TGU H994P1. Observational data were obtained in 2014-2015 with the 1.8m VATT telescope of the Vatican Observatory on Mt Graham, Arizona. Two-dimensional classification in the MK system is given for about 65% of stars.
