Nebulous Stars Research Articles

New Herbig–Haro objects and outflows in the Mon R1 association

ABSTRACT We present the results of a narrow-band Hα and [S ii] imaging survey of the Mon R1 association performed with the 1-m Schmidt telescope at Byurakan Observatory. Our observations covered a 1° field near the centre of the association. As a result of this study, 20 new Herbig–Haro knots were discovered, some of which form collimated outflows. Among the most extended ones are HH 1203 and HH 1196, which have a length of 1 pc or even more. During the search for the probable sources of HH objects, several new nebulous stars were found. A list of all nebulous stellar objects in the Mon R1 area under study is presented, with detailed descriptions of the most interesting ones. The near-infrared data from the GLIMPSE360 and WISE surveys revealed several more objects related to Mon R1, some of which had optical counterparts, as well as helped to identify at least three probable H2 collimated flows from the deeply embedded pre-main-sequence objects. The probable members of Mon R1 were selected by their distances; their bolometric luminosities and extinctions were estimated. Among the outflow sources, three embedded objects with luminosities greater than 10 L⊙ were found. The mean distance to the Mon R1 complex is estimated as 715 pc.

Fifth “dark” force completely change our understanding of the universe

For something that’s literally as old as the universe, dark matter doesn’t get much attention outside scientific circles. Maybe that’s because, other than a short-lived SyFy series and a late-period Randy Newman album, this nebulous star stuff has had a tough time breaking the pop-culture barrier. But the truth is that today, dark matter has never mattered more. Our own Milky Way is embedded in a massive cloud of it, we’re looking for its interactions deep inside the earth, and there are whole galaxies without it. So what is dark matter, anyway? Why can’t scientists get enough of the stuff, even though they can’t actually find it? What deep, dark secrets does it hold? And could it ultimately shape the future of life as we know it? DOI:10.20193/ijmri.v3i1.325

William Herschel and The Planetary Nebulae

At the close of the paper I give the location of half-a-dozen planetary nebulae, as I call them. These are celestial bodies of which as yet we have no clear idea and which are perhaps of type quite different from those that we are familiar with in the heavens. I have already found four that have visible diameter of between and 30 seconds. These bodies appear to have disk that is rather like planet, that is to say, of equal brightness all over, round or somewhat oval, and about as well-defined in outline as the disk of the planets, of light strong enough to be visible with an ordinary telescope of only one foot, yet they have only the appearance of star of about ninth magnitude.Herschel to Jerome Lalande, 17 March 1785 (in French).1An Unexpected DiscoveryIn the summer of 1782 King George III appointed William Herschel (1738-1822) astronomer to the court at Windsor Castle. On 7 September, month after he took up residence at nearby Datchet, Herschel was engaged in his long-established search for double stars when he came across an object near v Aquarii that was unlike anything he had ever seen before:A curious Nebula, or what else to call it I do not know, it is of shape somewhat oval, nearly circular, and with this power [460] appears to be 10 or 15 diameter. It is of the same shape with 278, but much less in appearance, with 932 it is still the same shape but much larger. So that its appearance seems to follow the law of magnifying, from whence it is clear that it is of some real magnitude in the heavens and not glare of light. The brightness in all the powers does not differ so much as if it were of planetary nature, but seems to be of the starry kind, tho' no star is visible with any power. It is all over of nearly the same brightness. The compound eyepiece will not distinguish it from fixt star, at least not sensibly....2It had the pale light of nebula but the disk of planet, and eventually he would name it 'planetary nebula', the term that astronomers have used ever since for this class of objects.But what was it? This was puzzle that would haunt Herschel for the forty years remaining to him.A planetary nebula is in fact an emission nebula consisting of an expanding glowing shell of ionized gas ejected from an old red giant star late in its life. (In this example, as more often than not, Herschel was unable to discern the central star that remained.) Such quasi-spherical shell of luminous gas will appear brightest at the outer edges, which are relatively well-defined as it is the shock-front of the expanding cloud, in contrast to globular cluster of stars which is brightest at the centre but has poorly-defined outer limits. In the years to come, as he became increasingly familiar with clusters of stars, Herschel quickly developed his great interpretive tool - the concept of gravitational attraction operating over time to produce the clusters - but planetary nebulae would refuse incorporation into this scheme of things. And when in 1790 he came to accept that, in addition to stars, the universe also contained clouds of luminous ('true') nebulosity, the planetary nebulae would again prove incalcitrant.Is It Moving?Eighteen months earlier he had encountered a nebulous star or perhaps comet, and after four days this object (which we know as the planet Uranus) had shown by its movement that it was close at hand, member of the solar system. Was the object near v Aquarii also member of the solar system? Ninety minutes after he discovered it, Herschel checked its position, but - not surprisingly - it had not (yet) moved.3Three weeks later, on 30 September, he checked again: Nebula near v Aquarii is in the same place and of the same shape.4Ten months then passed, and on 30 July 1783 - with his search for double stars almost complete and his new and larger 20-ft reflector soon to be commissioned - Herschel interrupted his current programme of examination of Messier nebulae to revisit the mysterious object:Nebula. …

The construction of the heavens: William Herschel's cosmology

Introduction Part I. Herschel's Exploration of the Cosmos: 1. The making of an astronomer 2. Our neighbours among the stars 3. The riddle of the nebulae: true nebulosity? 4. The riddle of the nebulae: true nebulosity rejected 5. The riddle of the nebulae: true nebulosity confirmed 6. Retrospect: Herschel and the construction of the heavens Part II. Herschel's Cosmological Papers in Philosophical Transactions: 7. 1783: 'On the proper motion of the sun and solar system' 8. 1784: 'Observations tending to investigate the construction of the heavens' 9. 1785: 'On the construction of the heavens' 10. 1789: 'Remarks on the construction of the heavens' 11. 1791: 'On nebulous stars' 12. 1802: 'Remarks on the construction of the heavens' 13. 1811: 'Observations relating to the construction of the heavens' 14. 1814: 'Observations relating to the sidereal part of the heavens' Index.

PMS and ZAMS stars associated with the dark cloud LDN 1655

We give results of a low-resolution optical spectroscopic study of the bright nebulous stars conforming the tight stellar trapezium embedded in IRAS06548-0815, of the exciting star of IRAS06547-0810, and of the stars associated with reflection nebulae (R-or N-stars) NJ065703.0–081421, NJ065714.1–081016, IRAS06548-0815 D and IRAS06548-0815 G, all objects scarcely observed and apparently pertaining to the dark cloud LDN 1655. Our results given here combined with the corresponding 2MASS near infrared photometry enables us to estimate a photometric distance to LDN1655 of 1.9±kpc and to locate the trapezium stars on the (logL∗/L⊙,logTeff) or HR diagram in an attempt to disclose about their true nature.The spectroscopy of IRAS06548-0815 revealed two classic T Tauri, two Herbig Ae/Be stars, four weak-line T Tauri stars, and two probable lithium-rich stars. Additionally, we found that the R-star IRAS06547-0810 is excited by a single B1(V) star, that IRAS06548-0815 D is excited by a SpT. B2/B3(V) star, NJ065703.0-081421 and NJ065714.1-081016 are excited by a B3/B4(V) emission star and an A6(V) star, respectively. The brightest near infrared source of the trapezium, IRS1, has an infrared luminosity comparable to a highly reddened O8(V) star (AV≈29m). The second brightest near infrared source of the trapezium, IRAS06548-0815 C is, optically, a single classical T Tauri star of spectral type K4/K5, but is a resolved binary in the 2MASSKs band, both components being of about the same brightness.

V733 Cep (Persson's Star): A New FU Orionis Object in Cepheus

Persson recently found that a faint star had appeared in a cloud in Cepheus. A CCD image shows a R ~ 17.3 nebulous star, now known as V733 Cep, located in the L1216 = Cep F cloud at the apex of a cavity in the cloud. Infrared photometry indicates a modest infrared excess. Optical spectroscopy shows a well-defined Li I λ6707 line, and blueshifted absorption troughs at the Hα and Na I D lines extending to at least 200 km s-1, indicative of a massive fast wind. An infrared 1-4 μm spectrum of V733 Cep shows the presence of strong water vapor features, and is almost identical to a similar IR spectrum of FU Ori that is reddened by AV = 8 mag. Assuming an intrinsic energy distribution similar to that of FU Ori, V733 Cep has a luminosity of about 135 L⊙ at the assumed distance of 800 pc. The star was detected by the Midcourse Space Experiment satellite at 8.3 μm, but not by IRAS. Nor is it detected at 850 μm, indicating that while the star possesses circumstellar material it is not surrounded by a significant cool envelope. A 12CO(3-2) map shows what appears to be a small molecular outflow along the same axis as the cavity seen in optical images. There is evidence for a limited amount of other low- and medium-mass star formation in the Cep F cloud. The totality of the evidence strongly indicates that V733 Cep is a new FU Ori-type object that must have erupted sometime between 1953 and 1984.

Penetrating the “zone of avoidance”. III. A survey for obscured galaxies in the region 120° ≤ ℓ ≤ 130°, -10° ≤ b ≤ +10°

As the third part in a series of papers on galaxies in the “zone of avoidance" (ZOA) of the Milky Way we present a compilation of 1161 galaxies discovered during a systematic search on Palomar Observatory Sky Survey (POSS) red-sensitive prints. The region searched comprises 200 square degrees, at 120° ≤ ℓ ≤ 130°, -10° ≤ b ≤ +10°. In addition to galactic, equatorial and rectangular coordinates, we list maximum and minimum optical diameters derived from both the red- and blue-sensitive prints, could assign a morphological type to some of the objects and made cross-checks with the IRAS PSC and several radio catalogues. A test for completeness suggests, that our catalogue should be complete down to a limiting galaxy-diameter of . An asymmetric distribution of the galaxies with respect to the galactic equator was found and is discussed by comparing it with the locations of optically visible dust clouds and/or the distribution of IR-emitting dust material. A comparison between the distribution of the galaxies and the IRAS intensity maps led to the identification of four possible clusterings. As a byproduct of our galaxy search, two new planetary nebulae, nebulous stars at the position of a strong cold IRAS point source, and a nearby dwarf irregular galaxy could be detected.

Evidence for circumstellar discs around nebulous stars in the Taurus dark clouds

Evidence for circumstellar discs around nebulous stars in the Taurus dark clouds

CCD images of suspected Herbig-Haro objects

view Abstract Citations (126) References (63) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS CCD images of suspected Herbig-Haro objects. Hartigan, P. ; Lada, C. J. Abstract Charge-coupled-device images in V, R, I, and H-alpha are presented for ten regions suspected to contain Herbig-Haro objects, including 11 of the 37 HH candidates listed by Gyulbudaghian et al. (1978). Four of the 11 are HH objects; the rest are either nebulous stars, reflection nebulas, or plate flaws. The images of R CrA, Cep A, and NGC 7129 shed considerable light on the details of star formation in these regions. More than a dozen new HH objects have been identified in these regions; the data have been used to investigate the nature of energetic outflow activity around these three objects. Publication: The Astrophysical Journal Supplement Series Pub Date: November 1985 DOI: 10.1086/191077 Bibcode: 1985ApJS...59..383H Keywords: Charge Coupled Devices; Herbig-Haro Objects; Pre-Main Sequence Stars; Astronomical Catalogs; Data Reduction; H Alpha Line; Reflection Nebulae; Stellar Evolution; Stellar Spectra; Astronomy full text sources ADS | data products SIMBAD (176)

AN INTERPRETATION OF THE SPECTRUM OF THE RED RECTANGLE.

ABSTRACT Results are reported for multichannel spectrophotometric observations of the strong IR source centered on the nebulous star HD 44179 and the associated Red Rectangle (RR) nebula, which were conducted over the wavelength range from 0.35 to 1.1 microns. The stellar spectrum is found to be anomalous, with a large Balmer absorption jump and a substantial IR excess. It is shown that the RR is apparently a reflection nebula, has the same Balmer jump as the star, and is redder than the star. Attempts are made to fit the stellar spectrum to model atmospheres for a B star with an abnormal envelope and for a low-gravity F star. The total luminosity of the RR is estimated, its surface brightness is analyzed, and the ratio of the nebula's surface brightness per sq arcsec to that of the star is evaluated. The chemical composition of the dust grains in the RR is considered.

INFRARED OBSERVATIONS OF LATE-TYPE STARS IN NEBULAE.

ABSTRACT Two- to 18- observations of five late-type stars involved with nebulae reveal no infrared excesses near 10 . This fact, coupled with the presence of nebular structures resembling wakes or bow shocks, suggests that the stars have randomly encountered the nebulae. Key words: infrared photometry - nebulous stars

Infra-Red Observations of Young Stars-III: NEBULOUS EMISSION-LINE STARS

Multifilter infra-red observations of early-type nebulous stars are presented in the 2 to 22 µ region. Emission features in the 10 µ region are found in the stars AB Aur and V380 Ori. It is found that stars associated with cometary nebulae are characterized by large [11]–[18] indices and this is discussed in the context of a possible picture of these nebulae.

Commission 8. (Meridian Astronomy.)

In connection with the plans of the Pulkovo Observatory for removing one of their vertical circles to the southern hemisphere the following recommendation was proposed by Dr Morgan and seconded by Prof. Boss: “The Commission regards the proposal of the Pulkovo Observatory to establish the Vertical Circle in as nearly equal a southern latitude as possible with great sympathy. We believe this will be of very great value in the improvement of fundamental decimations.”Dr Lundmark read a report on the programmes for the Lund meridian circle, which programmes include stars of special interest, such as long- and short-period variables, extremely red non-variable stars, B-emission stars, moving clusters, nebulous stars, nuclei of planetary nebulae and of anagalactic objects, etc. The definite programme will contain at least 3000 stars, results for some 400 of which have already been obtained. It is planned to extend the observations to stars in the southern hemisphere as soon as financial conditions will permit the erection of a southern station.

The color of the nebulous stars.

The color of the nebulous stars.

New nebulae and nebulous stars.

New nebulae and nebulous stars.

New Nebulae and Nebulous Stars.

New Nebulae and Nebulous Stars.

Our Astronomical Column

A NEW NEBULOUS STAR.'Mr. Barnard, in Astronomische Nachrichien, No. 3101, gives a brief account of a new nebulous star that he found when photographing, on May 31 last, a region situated in the Milky Way, 18h. 10m., – 20°. This star B.D. -– 19°.4953), when examined (visually) with his 12-inch, was quite devoid of nebulosity owing to the brightness of the star in question, but the photograph showed a faint nebulosity of about 15′ in diameter symmetrically surrounding it. A former photograph taken in 1889, July 28, indicated also the same nebulosity. The exposure in the former case was of 3h. 29m. duration, a Willard lens of 6-inch aperture being used. The position of the star for 1860 was R.A. 18h. 9m. 23.2s., Decl. – 19° 42′.7.

A New Nebulous Star, and Corrections to Dreyer's NGC

Astronomische NachrichtenVolume 130, Issue 5 p. 77-80 Article A New Nebulous Star, and Corrections to Dreyer's NGC E. E. Barnard, E. E. Barnard Mount HamiltonSearch for more papers by this author E. E. Barnard, E. E. Barnard Mount HamiltonSearch for more papers by this author First published: 1892 https://doi.org/10.1002/asna.18921300506AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume130, Issue51892Pages 77-80 RelatedInformation

Photographic Nebulosities and Groups of Nebulous Stars

Photographic Nebulosities and Groups of Nebulous Stars

Our Astronomical Column

The Photography of Faint Nebulæ—In the Journal of the British Astronomical Association for February, Dr. Max Wolf, of Heidelberg Observatory, contributes a note on a nebula surrounding ζ Orionis, the third star in the belt, which he has discovered on photographs taken with a 4-inch portrait lens. Some reproductions submitted to the Association show a large amount of nebulosity south-west of ζ, also nebulous ground around ζ, and a nebulous star north of ζ. Dr. Wolf's note is important, inasmuch as it indicates that the 4-inch portrait lens used at Heidelberg gives results which compare favourably with those obtained at Harvard with a much larger instrument, viz. the Bache equatorial of 8 inches aperture and 44 inches focal length. With regard to the use of portrait lenses for celestial photography, Dr. Wolf makes a few succinct remarks. In photographing the stars, the intensity of the image depends only upon the area of the lens employed, and an instrument of 20 inches diameter therefore requires 25 times less exposure than one 4 inches in diameter having the same focal length, in order to obtain the same number of stellar images. But it is a different thing with comets, nebulæ, and the like—bodies having a finite area. The intensity of the image at the focus then varies as the fraction (d/f)2, where d is the diameter of the object-glass, and f its focal length. If, therefore, the intensity of the light received with an aperture of 20 inches and focal length of 100 inches be expressed by 0˙04, that of a portrait lens of 4 inches aperture and 12 inches focus is 0˙11. This shows that in order to photograph the same faint nebula, the instrument of 20 inches aperture requires an exposure about three times as long as the 4-inch portrait lens.