A selection of known and newly-discovered northern hemisphere Cepheids and related objects are being monitored regularly through CCD observations at the automated Abbey Ridge Observatory, near Halifax, and photoelectric photometry from the Saint Mary's University Burke-Gaffney Observatory. Included is Polaris, which is displaying unusual fluctuations in its growing light amplitude, and a short-period, double-mode Cepheid, HDE 344787, with an amplitude smaller than that of Polaris, along with a selection of other classical Cepheids in need of additional observations. The observations are being used to establish basic parameters for the Cepheids, for application to the Galactic calibration of the Cepheid period-luminosity relation as well as studies of Galactic structure.
Reconstruction of Cepheid Radial Velocity Curves from the shape of the V-band Light Curves
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange(蔚蓝海岸大学,蔚蓝海岸天文台,法国国家科学研究中心,拉格朗日实验室);Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences(尼古拉·哥白尼天文学中心,波兰科学院);LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS(巴黎天文台,PSL大学,索邦大学,巴黎西岱大学,CY塞吉-巴黎大学,法国国家科学研究中心);French-Chilean Laboratory for Astronomy, IRL 3386, CNRS(法智利天文学联合实验室,IRL 3386,法国国家科学研究中心);Universidad de Concepción, Departamento Astronomía(康塞普西翁大学,天文学系);Instituto de Alta Investigación, Universidad de Tarapacá(高级研究所,塔拉帕卡大学)
We present the first analysis of Cepheid stars observed by the TESS space mission in Sectors 1 to 5. Our sample consists of 25 pulsators: ten fundamental mode, three overtone and two double-mode classical Cepheids, plus three Type II and seven anomalous Cepheids. The targets were chosen from fields with different stellar densities, both from the Galactic field and from the Magellanic System. Three targets have 2-minute cadence light curves available by the TESS Science Processing Operations Center: for the rest, we prepared custom light curves from the full-frame images with our own differenti…
We report on the results of a comprehensive search for Cepheid variable stars in the fields photometricallymonitored by the OGLE Galaxy Variability Survey. We identify 742 Cepheids not included in the first release of the OGLE Collection of Galactic Cepheids and reclassify several dozen previously published variables. The upgraded collection comprises 1974 classical, 1625 type II, and 119 anomalous Cepheids located in the area of about 3000 square degrees covering the disk and bulge of the Milky Way. We present the most interesting objects in our sample: an isolated group of long-period double…
Multi-mode Cepheids pulsate simultaneously in more than one mode of oscillation. They provide an independent means to test stellar models and pulsation theories. They can also be used to derive metallicities. In recent years, the number of known multi-mode Cepheids has increased dramatically with the discovery of a large number of Galactic double-mode Cepheids. To date, 209 double-mode Cepheids have been detected in the Galactic bulge and disk, mostly based on the Optical Gravitational Lensing Experiment's (OGLE) catalog. In this paper, we conduct a comprehensive search for double-mode Cepheid…
Variable stars in the northern Galactic plane from KISOGP
我们使用木曾天文台施密特望远镜上的木曾宽视场照相机对北平面进行了大规模的调查。KISOGP(KWFC Intensive Survey of the Galactic Plane)计划在约320平方米的I波段进行了40-70历元的观测。从2012年开始的5年。极限星等约为16.5 in I。在迄今为止的数据分析中,我们探测到了数千颗变星,包括大约100颗造父变星和700多颗Miras。其中大约90%以前没有被报道为变星,这表明在银河系平面上仍然有许多相对明亮的变星。
We present a realization of the maximum-likelihood (ML) technique, which is one of the latest modifications of the Baade--Becker--Wesselink (BBW) method. Our approach is based on non-linear calibrations of the effective temperature and bolometric correction which take into account metallicity and surface gravity. It allows one to estimate the key Cepheid parameters, the distance modulus, and the interstellar reddening, combining photometric and spectroscopic data (including the effective temperature data). This method is applied to a sample of 44 Galactic Cepheids, for which multiphase tempera…
The GALANTE optical photometric survey is observing the northern Galactic plane and some adjacent regions using seven narrow- and intermediate-filters, covering a total of 1618 square degrees. The survey has been designed with multiple exposure times and at least two different air masses per field to maximize its photometric dynamic range, comparable to that of Gaia, and ensure the accuracy of its photometric calibration. The goal is to reach at least 1% accuracy and precision in the seven bands for all stars brighter than AB magnitude 17 while detecting fainter stars with lower values of the …
The VELOCE Modulation Zoo I. Spectroscopic detection of non-radial modes in the first-overtone Cepheids BG Crucis, QZ Normae, V0391 Normae, and V0411 Lacertae
We present IRAM 30~m Telescope observations of the CO(1-0) and CO(2-1) emission lines in a sample of eight Cepheid variable stars. The CO(1-0) line is detected in four of the eight targets at a signal-to-noise of $>$3.5 confirming the presence of CO in Cepheid atmospheres. Two sources show strong absorption in both CO lines; this is likely related to contamination by cold molecular gas clouds along or close to the line of sight. The remaining two targets showed no strong features related to either CO line. These detections represent the first direct evidence for the presence of CO in Cepheid a…
Cluster membership for the long period Cepheid calibrator SV Vul
经典造父变星代表了距离尺度阶梯的第一步。当地计算的哈勃常数和从$Planck$的结果推导出的值之间的紧张关系引发了对这些距离校准器的新兴趣。星团成员资格提供了一个独立的距离测量,以及天体物理背景的研究,他们的恒星性质。在这里,我们报告在SV Vul附近发现了一个年轻的疏散星团,SV Vul是银河系中已知的最明亮的造父变星之一。$Gaia$ DR 2的数据显示,SV Vul是一个明确的天体测量和光度成员的新集群,我们命名为阿利坎特13。虽然分散,但阿利坎特13的人口相当充足,并包含另外三颗明亮的恒星,一颗早期-A明亮的巨星和两颗低光度的红超巨星。该星团的年龄约为30 Ma,标称距离为2.5 kpc。根据这个年龄,武星SV的质量应该在$10\:$ M $_{\odot}$附近,这与它的光度非常一致,接近于最近恒星模型所允许的造父变星的最高光度。
A Precision Multi-Band Two-Epoch Photometric Catalog of 44 Million Sources in the Northern Sky from Combination of the USNO-B and Sloan Digital Sky Survey Catalogs
下一代宽视场光学和无线电测量的一个关键科学驱动力是对时变天空的探索。这些调查将具有前所未有的敏感性和覆盖面,但在比调查寿命更长的时间尺度上发现变化的能力将受到限制。我们提出了一个新的精度,多历元的光度计目录,跨越60年,结合USNO-B和SDSS数据发布9目录。我们重新校准了原始USNO-B星表的测光,并创建了一个星表,其中包含位于北天DR 9足迹中的43,647,887个光学点源的两个测光时期,最多可达5个不同波段。重新校准的对象跨越的幅度范围14 < m < 20,是准确的$\approx$ 0.1马格。我们最大限度地减少虚假的对象和那些不准确的幅度通过识别和删除几个来源的系统误差在两个起源目录,重点虚假的对象,表现出大的视星等变化。在考虑了这些影响之后,我们发现$\approx$ 250,000颗恒星和类星体在USNO-B和SDSS DR 9时期之间显示出显著的(> 4 $σ$)亮度变化。讨论了该星表的历史价值及其在长时标、大振幅变星和类星体研究中的应用。
We have conducted a search for open clusters in the vicinity of classical Galactic Cepheids based on high-quality astrometry from the third data release (DR3) of the ESA mission Gaia to improve the calibration of the Leavitt law (LL). Our approach requires no prior knowledge of existing clusters, allowing us to both detect new host clusters and cross-check previously reported associations. Our Gold sample consists of 34 Cepheids residing in 28 open clusters, including 27 fundamental mode and 7 overtone Cepheids. Three new bona fide cluster Cepheids are reported (V0378 Cen, ST Tau, and GH Lup) …
We present a catalog of eclipsing binaries in the northern Galactic Plane from the Kiso Wide-Field Camera Intensive Survey of the Galactic Plane (KISOGP). We visually identified 7055 eclipsing binaries spread across $\sim$330 square degrees, including 4197 W Ursa Majoris/EW-, 1458 $β$ Lyrae/EB-, and 1400 Algol/EA-type eclipsing binaries. For all systems, $I$-band light curves were used to obtain accurate system parameters. We derived the distances and extinction values for the EW-type objects from their period--luminosity relation. We also obtained the structure of the thin disk from the distr…