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The article provides information about the discovery and characteristics of Wolf 359, a red dwarf star in the Leo constellation. Discovered by Max Wolf in 1918, it was found to emit less light than any other known star at the time. Although its large proper motion suggests it may be close to our solar system, its dimness indicates it could be far away, similar to another star called Groombridge 1830. The distance to Wolf 359 was measured in the 1920s, and Adriaan van Maanen used the 100-inch Hooker Telescope to determine its proximity to Earth. Despite being close, Wolf 359 appears faint due to its low luminosity. It is classified as a red dwarf, the most common type of star, and emits very little light compared to others. The article also mentions other dim stars, such as Van Biesbroeck's Star, that have been discovered since Wolf 359. The Sun and Wolf 359 have different trajectories within the Milky Way, and in the future, Wolf 359 may be much farther away from Earth. [Extracted from the article]

This article discusses a new technique being used to map the structure of the Milky Way galaxy with greater accuracy. Traditionally, our understanding of the galaxy's structure has been based on artists' impressions, but this new technique is providing more precise information. The focus is on the solar neighborhood, where our Sun is located, and the research being done to map stellar nurseries in this area. This research has revealed previously unseen structures and has provided new insights into the formation of baby stars in our part of the Milky Way. The technique involves using the Gaia mission to determine accurate distances to stars, which in turn helps determine the distances to interstellar gas clouds. This information is crucial for understanding the structure and history of our galaxy. One significant discovery is a 9,000-light-year-long wave-like structure called the Radcliffe Wave, which connects two stellar nurseries and contains a majority of the stellar nurseries in the solar neighborhood. The wave is the gaseous reservoir of the nearest spiral arm to our Sun, known as the Local Arm. The shape of the wave suggests that star formation is more dynamic than previously believed, and it may have been formed by external disturbances or supernova explosions. The discovery was made possible by advancements in 3D dust mapping techniques, and future space telescopes like the Nancy Grace Roman Space Telescope may uncover more structures in the galaxy. [Extracted from the article]

This article from Sky & Telescope discusses three globular star clusters in the constellation Hercules: M13, M92, and NGC 6229. M13, also known as the Great Cluster, is the most well-known and can be seen even under suburban skies. It is a cosmic hive of ancient suns and can be observed with a 4-inch telescope. M92 is less prominent but still a substantial target, and NGC 6229 is a dimmer cluster that can be detected with backyard instruments. The article provides instructions for locating these clusters in the night sky and describes the observations that can be made with different telescope sizes. [Extracted from the article]

Gaia should eventually discover and characterize thousands of giant exoplanets, says ESA's Sahlmann, but it takes time and patience - astronomers really need many years of data. DIAGRAM: THE GAIA REVOLUTION DIAGRAM: THE GAIA REVOLUTION PHOTO (COLOR): GAIA'S SKY This all-sky map uses data from more than 1.8 billion stars observed by Gaia. They nicknamed this galaxy Gaia-Enceladus, after the mythological giant (and son of the Earth goddess Gaia) who was buried under Sicily's Mount Etna, driving its volcanic activity. Moreover, Gaia scientists produced an open-source software package, Gaia Sky, advertised as a "3D universe simulator with support for more than a billion objects.". [Extracted from the article]

FEATURES STELLAR FRONTIERS FAMILY PORTRAIT A trio of stars make up 40 Eridani, all of which are fainter and smaller than the Sun: 40 Eridani A, an orange dwarf (foreground); 40 Eridani B, a white dwarf so hot it's actually blue; and 40 Eridani C, a red dwarf, the most common type of star in the galaxy. DIAGRAM: A GEM IN THE RIVER The easiest white dwarf to see in backyard telescopes is unquestionably 9.5-magnitude 40 Eridani B, which lies 83" east-southeast of 4.4-magni- tude 40 Eridani A, also known as Omicron2 ( 2) Eridani. Although some sources list Sirius B as the first white dwarf discovered, that distinction actually goes to 40 Eridani B. In backyard telescopes, Sirius B is a challenging target, while 40 Eridani B is relatively easy to spot. Both Sirius B and 40 Eridani B are as hot as blue main-sequence stars of spectral type B. Sirius B's surface temperature is 25,000 kelvin and 40 Eridani B is also hot, with a surface at 17,000K - nearly three times the Sun's temperature of 5800K. [Extracted from the article]

The cluster graduated to professional status as Collinder 399 (Cr 399) thanks to a comprehensive survey of open clusters that Swedish astronomer Per Collinder compiled in 1931. OBSERVING Suburban Stargazer JULY 2023 OBSERVING Poor Vulpécula, the Fox. [Extracted from the article]

For a large collection of stars, like an open cluster or a globular cluster, astronomers can calculate a rough distance estimate by plotting each constituent star's color (or temperature) against its apparent brightness. The Cosmos As mentioned before, Edwin Hubble discovered the proportional relation between a galaxy's distance and its apparent recession velocity, the latter derived from the observed redward shift of the galaxy's light. A galaxy at a redshift of z = 10 has a light-travel-time distance of 13.3 billion years: We see the galaxy as it appeared 13.3 billion years ago, when the universe was just half a billion years old. FEATURES Cows can't jump over the moon, no one has ever touched a star, and according to the opening crawl of Star Wars, galaxies are "far, far away.". [Extracted from the article]

Two years later at Kentucky's Twin Lakes Star Party (also at latitude 37°N) in my 4.2-inch rich-field telescope at 16× and 64× the arresting big splash of mixed bright and dim stars of NGC 2451 - anchored by the brightest cluster member, orange c Puppis - was very nice. An orange star lies between the two clusters, another is on NGC 884's western edge, a third is near its center, and two more orange stars ornament this cluster's northeastern side. Both rich, young clusters include spectral type B and A super-giant stars among their gems, while NGC 884 also contains some M-type red supergiants. A star that appears to be the central star of the planetary nebula can't be, since the true central star's magnitude is only 18. [Extracted from the article]

FEATURES CELESTIAL CARTOGRAPHY From earliest times astronomers were aware that among the fixed stars there were a few, equally fixed but un-star-like objects which appeared to them as "misty patches" or "little clouds". Bode and Uranographia One obvious candidate is the wonderful Uranographia, which was produced by the German astronomer Johann Elert Bode. Bode included more than 2,000 nebulae and hundreds of double stars based on the observations of British astronomer William Herschel, who surveyed the heavens in the late 18th century from England with reflector telescopes of 6, 12, 18.7, and (ultimately) 48 inches in aperture. The number of deep-sky objects plotted would seem to make Vorstellung Der Gestirne the first usable deep-sky atlas - but Bode went further by adding two special charts depicting nebulae and double stars in greater detail. [Extracted from the article]

OBSERVING To celebrate 20 years of Sue French's stellar contributions to Sky & Telescope, we will be sharing the best of her columns in the coming months. PHOTO (COLOR): Left: A short star-hop from Kaus Australis, the southernmost star in the Sagittarius Teapot asterism, will lead you to the interesting planetary nebula NGC 6563 floating in a rich star field. PHOTO (COLOR): Visible even in small telescopes, NGC 6445 shares the field in low-power views with the brighter globular cluster NGC 6440 just 22' to its south-southweest. [Extracted from the article]

Wolf-Rayet (WR) stars are an intrinsically bright class named after two researchers who identified them in the 19th century (see Steve Gottlieb's article for more detail on WR stars and their nebulae, S&T: Aug. 2019, p. 28). Two of the most spectacular WR nebulae in the sky are the Crescent Nebula in Cygnus (NGC 6888) and Thor's Helmet (NGC 2359) in Canis Major. If I were to find a WR star with the absolute magnitude of RW Cephei (-9.4), I could be looking at an object potentially 25 million light-years away, similar to that of M51 (the Whirlpool Galaxy). [Extracted from the article]

As supernova-powered shock waves swept through the region, they compressed dust and gas into what are now star-forming clouds lining the cavity's edge. MILLIONS OF YEARS AGO, supernova blasts cleared a giant hollow in space, triggering the next generation of stars in their wake. Interactive map at https://is.gd/PerTau PHOTO (COLOR): The Perseus and Taurus star-forming clouds lie on opposite sides of a large cavity. [Extracted from the article]

The article explains how to obtain cosmic perspectives using a telescopic eyepiece. Visualizing the diameter of a cluster in terms of the 4.4 light years separating the Sun from its stellar neighbor Alpha Centauri will give an estimate of a star ball's measurement. The brightness of stars would depend on their distances and a formula is used to find the actual size and magnitude of a star. A number of stars can be seen from the Pleiades cluster at a distance of 440 light years.

Discusses several computational factors to measure cosmic distances. Observational facts which suggest that the universe is accelerating in its expansion; Reasons Hubble diagrams use luminosity distance; How astronomers concluded that the universe is expanding; Equation for the Doppler-shift and special-relativity; Information on astronomical constants.

Meanwhile, Poggio and her colleagues mapped more than 750,000 of the most massive main-sequence stars, 353 newborn star clusters, and 1,923 young Cepheid variables, giant pulsating stars with well-known distances. COLUMNS/DEPARTMENTS MILKY WAY WHILE ASTRONOMERS generally agree that the Milky Way has four major spiral arms, what they look like is still an open question. In the January Astronomy & Astrophysics, Xu and his colleagues picked out 9,750 stars of spectral type O to B2, massive and brilliant stars that are at most 20 million years old and thus not too far from their birthplaces in the spiral arms. [Extracted from the article]

BETELGEUSE MIGHT ACTUALLY BE smaller, and therefore closer, than previously thought, Meridith Joyce (Australian National University) and colleagues report in the October 10th Astrophysical Journal. By inputting this swell-and-contract rhythm into a computer simulation, Joyce calculated Betelgeuse's average girth: between 702 and 880 times the Sun's diameter. [Extracted from the article]

Novae as Yardsticks "In recent years, the luminosities of new stars have been established with considerable accuracy, and our knowledge of the absorption of light in space has improved so much that Dr. Dean B. McLaughlin, of the University of Michigan Observatory, has made a study of the space distribution for some 100 novae for which reasonably good data are available…. ºSeptember 1995 Heavenly Brew "Ethyl alcohol, or ethanol (CH3CH2OH) - the organic compound that gives beer, wine, and liquor their intoxicating powers - reveals itself … by emitting discrete spectral lines at millimeter wavelengths. Although first detected toward the galactic center in 1975, ethanol has eluded subsequent searches of its expected habitat … Now, however, a British team has located a huge reservoir of the evasive compound on the outskirts of a young star-forming region…. [Extracted from the article]

The article describes several stars in the constellation Sagittarius. The open cluster NGC 6520 and the dark nebula Barnard 86 are considered as some of the prettiest non-Messier sights in the constellation. The double star Ara 1520 at the NGC 6568 was discovered by S. Aravamudan of the Nizamiah Observatory in India. The NGC 6583 cluster is said to be 6,700 light-years away.

The article explores the 12 globular clusters of constellation Hercules. They include the Messier 92, which lies about two-fifths of the way from Iota to Eta Herculis, the NGC 6229, which is considered the dimmer globular cluster which is located 4.8 degrees east northeast of Tau Herculis and the northernmost star, 56 Herculis, a double star with a yelow primary and a faint companion east, among others. Others include Vyssotsky 1-2, Markov 1 and Webb's Death.

ASTRONOMERS HAVE DISCOVERED a collection of young stars in a surprising location: the Milky Way's halo. There's not much star-making gas in the Milky Way's halo, as most of the gas is too hot and diffuse to collapse into new suns. It's difficult to determine the distance to hydrogen gas, but based on the stars' distances, the astronomers estimate that the Magellanic Stream is roughly half as far away as previously thought. [Extracted from the article]

The first book is Sir Robert Ball's A Popular Guide to the Heavens, images from which handsomely adorn the opening spread of Brasch's piece. "The whole [of Messier 13] contains at least 5,000 stars …" "The light of the [Great Nebula in Andromeda] is such as would be given by vast numbers of stars crowded together [but] it is altogether premature to argue … that the nebula is really an enormous system of stars far away". Ball and his contemporaries knew of only a single galaxy, the Milky Way; today we count them in the billions. [Extracted from the article]

Reports on findings about Brocchi's cluster according data gathered by the Hipparcos satellite and released by the European Space Agency. Characteristics of a cluster; Parallax measurements; Nominal parallax distances.

Focuses on determining parallaxes of stars near the Sun. Research Consortium on Nearby Stars' findings on stellar output; Identification of nearby stars; Challenge in spotting red dwarf star; Star systems near the Sun.

The article reports on a study by Marion Dierickx and Abraham Loeb of Harvard University in the to be published in the "Astrophysical Journal," which argues that the most distant stars in the outer reaches of the Milky Way galaxy might be members of the Sagittarius dwarf galaxy.

The article reports that Paula Jofre of the University of Cambridge in Great Britain has discovered an alternative method to stellar spectra in measuring the distance of stars.

The article focuses on the star Cor Caroli, or Heart of Charles. It is believed that the star was originally named Cor Caroli Regis Martyris for King Charles I of England. Cor Caroli lies about 110 light-years away with a magnitude of 2.8. Cor Caroli occupies a central location and helps guide the way to other spring sky sights.

Presents an article which details the observation of T Pyxidis, the nova that is found within the southern constellation Pyxis. Description of the star; Process of star brightenings; Location of the star.

Views the distance of the stars in light years. Use of parsecs in meaasuring the distance of stars from the earth; Implication of observations of the cosmos; Measurements of light years.

The article reports on the continued debate over the distance of SS Cygni star.

Excerpts from articles published in previous issues of this magazine are presented which include a May/June 1935 piece about the problem of determining the distances of stars, a May 1960 item on the dedication exercises of Kitt Peak National Observatory in Arizona, and a May 1985 article on the importance of color in determining the true nature of a planet.

The article focuses on the distance between the double stars Gamma Virginis or Porrima. It notes that the double stars are found 15° northwest of the star Spica. It recalls that the double stars appeared as one in most telescopes in June 2005 as they closed up and were separated by a distance of only 0.4 arc-second. The stars are said to be 39 light-years apart and shine at 3.5 magnitude.

Corrections to two articles published in previous issues are presented, including the attempt to measure stellar parallax and the nationality of playwright George Bernard Shaw.

The article assesses the height of the double star Gamma Velorum, which is 47° south of the celestial equator, from an observer living at latitude 40° North. For a person living at that coordinate, the altitude of the celestial pole is equal to the person's latitude. To determine the celestial equator, the person's latitude should be subtracted to the maximum height of Gamma Velorum the celestial equator, which is 90°. The height then of the double star is 3°.

The article reports the widening of the gap between the twin stars of Gamma Virginis, or Porrima, in 2007. Porrima appeared to be single in 2005 because its twin stars were at their closest, says the author. The predicted distance between the two stars will be 0.80" on April 1 and the gap will be wider by July 1. According to the author, a 6-inch telescope will barely resolve the pair, so observers should look for the star's diffraction pattern.

The article provides information on the night stars closest to the Earth. The author says that if brightness will be considered, Sirius and Canopus could be considered candidates, but they are not the nearest. Alpha Centauri, the third bright star at night, is the closest stellar system to the Earth with a distance of 3¼ light years, according to astronomer Thomas Henderson. Alpha Centauri is also known as Rigil Kentaurus, meaning the centaur's foot.

Reports updates on the measurement of the distance to a star through its trigonometric parallax. Result of the measurement of the parallaxes of bright stars, conducted with the European Space Agency's Hipparcos satellite in 1997; Use of the Very Long Baseline Array technique to measure parallaxes; Launch of the Gaia satellite of the European Space Agency.

Provides an astronomical information on the star Mira. Magnitude; Location; Distance from the Earth; Value of the angular diameter.

Focuses on the bias of ground-based measurement of parallaxes. Ground-based observers' overestimation of the distances of stars more than 100 light-years away; Emergence of evidence favoring younger globular star clusters.

Reports that astronomers have the precise measurements for the Vega and Altair parallaxes. How the measurements are made; Awaiting positional data from Hipparcos astrometric satellite.